Finally block causing exception to throw twice with CryptoStream?

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  • TC
    #1

    Finally block causing exception to throw twice with CryptoStream?

    Hey All,

    I posted this to the Crypto users group and forgot to add the VB.Net users
    group. I apologize for any confusion.

    I have been testing a try / catch / finally block and purposely raising
    exceptions and I've noticed that if an exception of "Length of the data to
    decrypt is invalid." is raised with the CryptoStream object, later this
    exception will get raised a second time and thrown to the caller when trying
    to close the stream in a Finally block.

    For example:

    Try
    ' Do tasks that cause CryptoStream to throw invalid length while
    decrypting

    Catch ex as CryptographicEx ception
    ' Handle exception here
    Finally
    If Not MemStream is Nothing then
    ' No 2nd exception thrown here
    MemStream.Close ()
    End If

    If Not CrypStream is Nothing then
    ' Exception thrown a 2nd time
    CrypStream.Clos e()
    End If


    Has anyone else experienced the above?

    If so, how to address the problem or is this a bug?




    Tags: None
    • kimiraikkonen
      #2
      Re: Finally block causing exception to throw twice with CryptoStream?

      On May 18, 7:36 pm, "TC" <getmyemai...@y ahoo.comwrote:
      Hey All,
      >
      I posted this to the Crypto users group and forgot to add the VB.Net users
      group. I apologize for any confusion.
      >
      I have been testing a try / catch / finally block and purposely raising
      exceptions and I've noticed that if an exception of "Length of the data to
      decrypt is invalid." is raised with the CryptoStream object, later this
      exception will get raised a second time and thrown to the caller when trying
      to close the stream in a Finally block.
      >
      For example:
      >
      Try
      ' Do tasks that cause CryptoStream to throw invalid length while
      decrypting
      >
      Catch ex as CryptographicEx ception
      ' Handle exception here
      Finally
      If Not MemStream is Nothing then
      ' No 2nd exception thrown here
      MemStream.Close ()
      End If
      >
      If Not CrypStream is Nothing then
      ' Exception thrown a 2nd time
      CrypStream.Clos e()
      End If
      >
      Has anyone else experienced the above?
      >
      If so, how to address the problem or is this a bug?
      TC,
      Do you experience the same problem when you use "Using-End Using"
      statement instead of Try-Catch for CryptoStream object?

      Thanks,

      Onur Güzel

        Comment

        • TC
          #3
          Re: Finally block causing exception to throw twice with CryptoStream?

          Hey Onur,

          So you would recommend something like the following:

          MyFunction(ByVa l encryptString as String) as String
          Try
          Using(MyCryptoS tream)
          ' Do Crypto tasks
          return MyEncryptedStri ng
          End Using
          Catch ex as CryptographicEx ception
          HandleCryptoExc eption ex
          Catch ex as Exception
          HandleException (ex)
          return Nothing
          Finally
          If Not MyMemoryStream Is Nothing Then
          MyMemoryStream. Close
          End If
          ' Do not close CryptoStream here as it causes duplicitous
          exception
          ' The 'Using' block will dispose of any CryptoStream resources
          End Function

          The above does not cause the duplicitous exception to be thrown.

          Thanks,

          Todd


          "kimiraikko nen" <kimiraikkonen8 5@gmail.comwrot e in message
          news:e75b9596-71bd-485e-863b-9fcc301312f6@a2 3g2000hsc.googl egroups.com...
          On May 18, 7:36 pm, "TC" <getmyemai...@y ahoo.comwrote:
          Hey All,
          >
          I posted this to the Crypto users group and forgot to add the VB.Net users
          group. I apologize for any confusion.
          >
          I have been testing a try / catch / finally block and purposely raising
          exceptions and I've noticed that if an exception of "Length of the data to
          decrypt is invalid." is raised with the CryptoStream object, later this
          exception will get raised a second time and thrown to the caller when
          trying
          to close the stream in a Finally block.
          >
          For example:
          >
          Try
          ' Do tasks that cause CryptoStream to throw invalid length while
          decrypting
          >
          Catch ex as CryptographicEx ception
          ' Handle exception here
          Finally
          If Not MemStream is Nothing then
          ' No 2nd exception thrown here
          MemStream.Close ()
          End If
          >
          If Not CrypStream is Nothing then
          ' Exception thrown a 2nd time
          CrypStream.Clos e()
          End If
          >
          Has anyone else experienced the above?
          >
          If so, how to address the problem or is this a bug?
          TC,
          Do you experience the same problem when you use "Using-End Using"
          statement instead of Try-Catch for CryptoStream object?

          Thanks,

          Onur Güzel


            Comment

            • kimiraikkonen
              #4
              Re: Finally block causing exception to throw twice with CryptoStream?

              On May 19, 1:10 pm, "TC" <getmyemai...@y ahoo.comwrote:
              Hey Onur,
              >
                  So you would recommend something like the following:
              >
                  MyFunction(ByVa l encryptString as String) as String
                      Try
                          Using(MyCryptoS tream)
                              ' Do Crypto tasks
                              return MyEncryptedStri ng
                          End Using
                      Catch ex as CryptographicEx ception
                          HandleCryptoExc eption ex
                      Catch ex as Exception
                          HandleException (ex)
                          return Nothing
                      Finally
                          If Not MyMemoryStream Is Nothing Then
                              MyMemoryStream. Close
                          End If
                          ' Do not close CryptoStream here as it causes duplicitous
              exception
                          ' The 'Using' block will dispose of any CryptoStream resources
                  End Function
              >
              The above does not cause the duplicitous exception to be thrown.
              >
              Thanks,
              >
              Todd
              >
              "kimiraikko nen" <kimiraikkone.. .@gmail.comwrot e in message
              >
              news:e75b9596-71bd-485e-863b-9fcc301312f6@a2 3g2000hsc.googl egroups.com...
              On May 18, 7:36 pm, "TC" <getmyemai...@y ahoo.comwrote:
              >
              >
              >
              >
              >
              Hey All,
              >
              I posted this to the Crypto users group and forgot to add the VB.Net users
              group.  I apologize for any confusion.
              >
              I have been testing a try / catch / finally block and purposely raising
              exceptions and I've noticed that if an exception of "Length of the data to
              decrypt is invalid." is raised with the CryptoStream object, later this
              exception will get raised a second time and thrown to the caller when
              trying
              to close the stream in a Finally block.
              >
              For example:
              >
              Try
                   ' Do tasks that cause CryptoStream to throw invalid length while
              decrypting
              >
              Catch ex as CryptographicEx ception
                  ' Handle exception here
              Finally
                  If Not MemStream is Nothing then
                      ' No 2nd exception thrown here
                      MemStream.Close ()
                  End If
              >
                  If Not CrypStream is Nothing then
                      ' Exception thrown a 2nd time
                      CrypStream.Clos e()
                  End If
              >
              Has anyone else experienced the above?
              >
              If so, how to address the problem or is this a bug?
              >
              TC,
              Do you experience the same problem when you use "Using-End Using"
              statement instead of Try-Catch for CryptoStream object?
              >
              Thanks,
              >
              Onur Güzel- Hide quoted text -
              >
              - Show quoted text -
              Hi,
              If it solves your problem, it's OK, however you can also try to put
              try-catch inside Using-End Using without "Finally" because "Using-End
              Using" does all the disposal operation:


              MyFunction(ByVa l encryptString as String) as String

              Using(MyCryptoS tream)
              Try
              ' Do Crypto tasks
              return MyEncryptedStri ng

              Catch ex as CryptographicEx ception
              HandleCryptoExc eption ex
              ' The 'Using' block will dispose of any CryptoStream
              resources
              End Using
              End Function


              Thanks,

              Onur Güzel

                Comment

                • TC
                  #5
                  Re: Finally block causing exception to throw twice with CryptoStream?

                  Ahhh... right... got it!

                  Thanks



                  "kimiraikko nen" <kimiraikkonen8 5@gmail.comwrot e in message
                  news:725ff39a-f310-49da-a447-a8bd6a563b3e@r6 6g2000hsg.googl egroups.com...
                  On May 19, 1:10 pm, "TC" <getmyemai...@y ahoo.comwrote:
                  Hey Onur,
                  >
                  So you would recommend something like the following:
                  >
                  MyFunction(ByVa l encryptString as String) as String
                  Try
                  Using(MyCryptoS tream)
                  ' Do Crypto tasks
                  return MyEncryptedStri ng
                  End Using
                  Catch ex as CryptographicEx ception
                  HandleCryptoExc eption ex
                  Catch ex as Exception
                  HandleException (ex)
                  return Nothing
                  Finally
                  If Not MyMemoryStream Is Nothing Then
                  MyMemoryStream. Close
                  End If
                  ' Do not close CryptoStream here as it causes duplicitous
                  exception
                  ' The 'Using' block will dispose of any CryptoStream resources
                  End Function
                  >
                  The above does not cause the duplicitous exception to be thrown.
                  >
                  Thanks,
                  >
                  Todd
                  >
                  "kimiraikko nen" <kimiraikkone.. .@gmail.comwrot e in message
                  >
                  news:e75b9596-71bd-485e-863b-9fcc301312f6@a2 3g2000hsc.googl egroups.com...
                  On May 18, 7:36 pm, "TC" <getmyemai...@y ahoo.comwrote:
                  >
                  >
                  >
                  >
                  >
                  Hey All,
                  >
                  I posted this to the Crypto users group and forgot to add the VB.Net
                  users
                  group. I apologize for any confusion.
                  >
                  I have been testing a try / catch / finally block and purposely raising
                  exceptions and I've noticed that if an exception of "Length of the data
                  to
                  decrypt is invalid." is raised with the CryptoStream object, later this
                  exception will get raised a second time and thrown to the caller when
                  trying
                  to close the stream in a Finally block.
                  >
                  For example:
                  >
                  Try
                  ' Do tasks that cause CryptoStream to throw invalid length while
                  decrypting
                  >
                  Catch ex as CryptographicEx ception
                  ' Handle exception here
                  Finally
                  If Not MemStream is Nothing then
                  ' No 2nd exception thrown here
                  MemStream.Close ()
                  End If
                  >
                  If Not CrypStream is Nothing then
                  ' Exception thrown a 2nd time
                  CrypStream.Clos e()
                  End If
                  >
                  Has anyone else experienced the above?
                  >
                  If so, how to address the problem or is this a bug?
                  >
                  TC,
                  Do you experience the same problem when you use "Using-End Using"
                  statement instead of Try-Catch for CryptoStream object?
                  >
                  Thanks,
                  >
                  Onur Güzel- Hide quoted text -
                  >
                  - Show quoted text -
                  Hi,
                  If it solves your problem, it's OK, however you can also try to put
                  try-catch inside Using-End Using without "Finally" because "Using-End
                  Using" does all the disposal operation:


                  MyFunction(ByVa l encryptString as String) as String

                  Using(MyCryptoS tream)
                  Try
                  ' Do Crypto tasks
                  return MyEncryptedStri ng

                  Catch ex as CryptographicEx ception
                  HandleCryptoExc eption ex
                  ' The 'Using' block will dispose of any CryptoStream
                  resources
                  End Using
                  End Function


                  Thanks,

                  Onur Güzel


                    Comment

                    • TC
                      #6
                      Re: Finally block causing exception to throw twice with CryptoStream?

                      Hey Onur,

                      Just to be clear, even though the 'Using' block is for the CryptoStream, it
                      will also dispose of the MemoryStream resources as well because it is within
                      that block (i.e. the 'Using' block not only applies to the IDisposable
                      interface of its calling object which, in this case, is the CryptoStream but
                      also the IDisposable interfaces available to objects within the block as
                      well)?

                      Thanks,

                      TC

                      "kimiraikko nen" <kimiraikkonen8 5@gmail.comwrot e in message
                      news:725ff39a-f310-49da-a447-a8bd6a563b3e@r6 6g2000hsg.googl egroups.com...
                      On May 19, 1:10 pm, "TC" <getmyemai...@y ahoo.comwrote:
                      Hey Onur,
                      >
                      So you would recommend something like the following:
                      >
                      MyFunction(ByVa l encryptString as String) as String
                      Try
                      Using(MyCryptoS tream)
                      ' Do Crypto tasks
                      return MyEncryptedStri ng
                      End Using
                      Catch ex as CryptographicEx ception
                      HandleCryptoExc eption ex
                      Catch ex as Exception
                      HandleException (ex)
                      return Nothing
                      Finally
                      If Not MyMemoryStream Is Nothing Then
                      MyMemoryStream. Close
                      End If
                      ' Do not close CryptoStream here as it causes duplicitous
                      exception
                      ' The 'Using' block will dispose of any CryptoStream resources
                      End Function
                      >
                      The above does not cause the duplicitous exception to be thrown.
                      >
                      Thanks,
                      >
                      Todd
                      >
                      "kimiraikko nen" <kimiraikkone.. .@gmail.comwrot e in message
                      >
                      news:e75b9596-71bd-485e-863b-9fcc301312f6@a2 3g2000hsc.googl egroups.com...
                      On May 18, 7:36 pm, "TC" <getmyemai...@y ahoo.comwrote:
                      >
                      >
                      >
                      >
                      >
                      Hey All,
                      >
                      I posted this to the Crypto users group and forgot to add the VB.Net
                      users
                      group. I apologize for any confusion.
                      >
                      I have been testing a try / catch / finally block and purposely raising
                      exceptions and I've noticed that if an exception of "Length of the data
                      to
                      decrypt is invalid." is raised with the CryptoStream object, later this
                      exception will get raised a second time and thrown to the caller when
                      trying
                      to close the stream in a Finally block.
                      >
                      For example:
                      >
                      Try
                      ' Do tasks that cause CryptoStream to throw invalid length while
                      decrypting
                      >
                      Catch ex as CryptographicEx ception
                      ' Handle exception here
                      Finally
                      If Not MemStream is Nothing then
                      ' No 2nd exception thrown here
                      MemStream.Close ()
                      End If
                      >
                      If Not CrypStream is Nothing then
                      ' Exception thrown a 2nd time
                      CrypStream.Clos e()
                      End If
                      >
                      Has anyone else experienced the above?
                      >
                      If so, how to address the problem or is this a bug?
                      >
                      TC,
                      Do you experience the same problem when you use "Using-End Using"
                      statement instead of Try-Catch for CryptoStream object?
                      >
                      Thanks,
                      >
                      Onur Güzel- Hide quoted text -
                      >
                      - Show quoted text -
                      Hi,
                      If it solves your problem, it's OK, however you can also try to put
                      try-catch inside Using-End Using without "Finally" because "Using-End
                      Using" does all the disposal operation:


                      MyFunction(ByVa l encryptString as String) as String

                      Using(MyCryptoS tream)
                      Try
                      ' Do Crypto tasks
                      return MyEncryptedStri ng

                      Catch ex as CryptographicEx ception
                      HandleCryptoExc eption ex
                      ' The 'Using' block will dispose of any CryptoStream
                      resources
                      End Using
                      End Function


                      Thanks,

                      Onur Güzel


                        Comment

                        • TC
                          #7
                          Re: Finally block causing exception to throw twice with CryptoStream?

                          Hey Onur,

                          Perhaps better said, in C#, one can do something like the following:

                          Using (object1, object2, object 3)
                          // Perform tasks
                          End Using

                          Is there a syntax for something similar in VB.Net or does one have to nest
                          the 'Using' statements like this:

                          Using (object1)
                          Using(object2)
                          // Perform tasks
                          End Using
                          End Using

                          Thanks,

                          TC

                          "kimiraikko nen" <kimiraikkonen8 5@gmail.comwrot e in message
                          news:725ff39a-f310-49da-a447-a8bd6a563b3e@r6 6g2000hsg.googl egroups.com...
                          On May 19, 1:10 pm, "TC" <getmyemai...@y ahoo.comwrote:
                          Hey Onur,
                          >
                          So you would recommend something like the following:
                          >
                          MyFunction(ByVa l encryptString as String) as String
                          Try
                          Using(MyCryptoS tream)
                          ' Do Crypto tasks
                          return MyEncryptedStri ng
                          End Using
                          Catch ex as CryptographicEx ception
                          HandleCryptoExc eption ex
                          Catch ex as Exception
                          HandleException (ex)
                          return Nothing
                          Finally
                          If Not MyMemoryStream Is Nothing Then
                          MyMemoryStream. Close
                          End If
                          ' Do not close CryptoStream here as it causes duplicitous
                          exception
                          ' The 'Using' block will dispose of any CryptoStream resources
                          End Function
                          >
                          The above does not cause the duplicitous exception to be thrown.
                          >
                          Thanks,
                          >
                          Todd
                          >
                          "kimiraikko nen" <kimiraikkone.. .@gmail.comwrot e in message
                          >
                          news:e75b9596-71bd-485e-863b-9fcc301312f6@a2 3g2000hsc.googl egroups.com...
                          On May 18, 7:36 pm, "TC" <getmyemai...@y ahoo.comwrote:
                          >
                          >
                          >
                          >
                          >
                          Hey All,
                          >
                          I posted this to the Crypto users group and forgot to add the VB.Net
                          users
                          group. I apologize for any confusion.
                          >
                          I have been testing a try / catch / finally block and purposely raising
                          exceptions and I've noticed that if an exception of "Length of the data
                          to
                          decrypt is invalid." is raised with the CryptoStream object, later this
                          exception will get raised a second time and thrown to the caller when
                          trying
                          to close the stream in a Finally block.
                          >
                          For example:
                          >
                          Try
                          ' Do tasks that cause CryptoStream to throw invalid length while
                          decrypting
                          >
                          Catch ex as CryptographicEx ception
                          ' Handle exception here
                          Finally
                          If Not MemStream is Nothing then
                          ' No 2nd exception thrown here
                          MemStream.Close ()
                          End If
                          >
                          If Not CrypStream is Nothing then
                          ' Exception thrown a 2nd time
                          CrypStream.Clos e()
                          End If
                          >
                          Has anyone else experienced the above?
                          >
                          If so, how to address the problem or is this a bug?
                          >
                          TC,
                          Do you experience the same problem when you use "Using-End Using"
                          statement instead of Try-Catch for CryptoStream object?
                          >
                          Thanks,
                          >
                          Onur Güzel- Hide quoted text -
                          >
                          - Show quoted text -
                          Hi,
                          If it solves your problem, it's OK, however you can also try to put
                          try-catch inside Using-End Using without "Finally" because "Using-End
                          Using" does all the disposal operation:


                          MyFunction(ByVa l encryptString as String) as String

                          Using(MyCryptoS tream)
                          Try
                          ' Do Crypto tasks
                          return MyEncryptedStri ng

                          Catch ex as CryptographicEx ception
                          HandleCryptoExc eption ex
                          ' The 'Using' block will dispose of any CryptoStream
                          resources
                          End Using
                          End Function


                          Thanks,

                          Onur Güzel


                            Comment

                            • kimiraikkonen
                              #8
                              Re: Finally block causing exception to throw twice with CryptoStream?

                              On May 20, 4:35 pm, "TC" <getmyemai...@y ahoo.comwrote:
                              Hey Onur,
                              >
                              Perhaps better said, in C#, one can do something like the following:
                              >
                              Using (object1, object2, object 3)
                              // Perform tasks
                              End Using
                              >
                              Is there a syntax for something similar in VB.Net or does one have to nest
                              the 'Using' statements like this:
                              >
                              Using (object1)
                              Using(object2)
                              // Perform tasks
                              End Using
                              End Using
                              >
                              Thanks,
                              >
                              TC
                              >
                              "kimiraikko nen" <kimiraikkone.. .@gmail.comwrot e in message
                              >
                              news:725ff39a-f310-49da-a447-a8bd6a563b3e@r6 6g2000hsg.googl egroups.com...
                              On May 19, 1:10 pm, "TC" <getmyemai...@y ahoo.comwrote:
                              >
                              >
                              >
                              Hey Onur,
                              >
                              So you would recommend something like the following:
                              >
                              MyFunction(ByVa l encryptString as String) as String
                              Try
                              Using(MyCryptoS tream)
                              ' Do Crypto tasks
                              return MyEncryptedStri ng
                              End Using
                              Catch ex as CryptographicEx ception
                              HandleCryptoExc eption ex
                              Catch ex as Exception
                              HandleException (ex)
                              return Nothing
                              Finally
                              If Not MyMemoryStream Is Nothing Then
                              MyMemoryStream. Close
                              End If
                              ' Do not close CryptoStream here as it causes duplicitous
                              exception
                              ' The 'Using' block will dispose of any CryptoStream resources
                              End Function
                              >
                              The above does not cause the duplicitous exception to be thrown.
                              >
                              Thanks,
                              >
                              Todd
                              >
                              "kimiraikko nen" <kimiraikkone.. .@gmail.comwrot e in message
                              >
                              news:e75b9596-71bd-485e-863b-9fcc301312f6@a2 3g2000hsc.googl egroups.com...
                              On May 18, 7:36 pm, "TC" <getmyemai...@y ahoo.comwrote:
                              >
                              Hey All,
                              >
                              I posted this to the Crypto users group and forgot to add the VB.Net
                              users
                              group. I apologize for any confusion.
                              >
                              I have been testing a try / catch / finally block and purposely raising
                              exceptions and I've noticed that if an exception of "Length of the data
                              to
                              decrypt is invalid." is raised with the CryptoStream object, later this
                              exception will get raised a second time and thrown to the caller when
                              trying
                              to close the stream in a Finally block.
                              >
                              For example:
                              >
                              Try
                              ' Do tasks that cause CryptoStream to throw invalid length while
                              decrypting
                              >
                              Catch ex as CryptographicEx ception
                              ' Handle exception here
                              Finally
                              If Not MemStream is Nothing then
                              ' No 2nd exception thrown here
                              MemStream.Close ()
                              End If
                              >
                              If Not CrypStream is Nothing then
                              ' Exception thrown a 2nd time
                              CrypStream.Clos e()
                              End If
                              >
                              Has anyone else experienced the above?
                              >
                              If so, how to address the problem or is this a bug?
                              >
                              TC,
                              Do you experience the same problem when you use "Using-End Using"
                              statement instead of Try-Catch for CryptoStream object?
                              >
                              Thanks,
                              >
                              Onur Güzel- Hide quoted text -
                              >
                              - Show quoted text -
                              >
                              Hi,
                              If it solves your problem, it's OK, however you can also try to put
                              try-catch inside Using-End Using without "Finally" because "Using-End
                              Using" does all the disposal operation:
                              >
                              MyFunction(ByVa l encryptString as String) as String
                              >
                              Using(MyCryptoS tream)
                              Try
                              ' Do Crypto tasks
                              return MyEncryptedStri ng
                              >
                              Catch ex as CryptographicEx ception
                              HandleCryptoExc eption ex
                              ' The 'Using' block will dispose of any CryptoStream
                              resources
                              End Using
                              End Function
                              >
                              Thanks,
                              >
                              Onur Güzel
                              TC,
                              To make sure that all of your disposable resources are disposed
                              clearly by Using statement, you can also use seperate "Using"s for
                              each disposable object like:

                              Using block1 As New DisposableObjec t1
                              'Statements here
                              End Using

                              Using block2 As New DisposableObjec t2
                              'Statements here
                              End Using

                              and so on...

                              Better ideas may exist of course.

                              Thanks,

                              Onur Güzel

                                Comment

                                • kimiraikkonen
                                  #9
                                  Re: Finally block causing exception to throw twice with CryptoStream?

                                  On May 20, 7:36 pm, kimiraikkonen <kimiraikkone.. .@gmail.comwrot e:
                                  On May 20, 4:35 pm, "TC" <getmyemai...@y ahoo.comwrote:
                                  >
                                  >
                                  >
                                  Hey Onur,
                                  >
                                  Perhaps better said, in C#, one can do something like the following:
                                  >
                                  Using (object1, object2, object 3)
                                  // Perform tasks
                                  End Using
                                  >
                                  Is there a syntax for something similar in VB.Net or does one have to nest
                                  the 'Using' statements like this:
                                  >
                                  Using (object1)
                                  Using(object2)
                                  // Perform tasks
                                  End Using
                                  End Using
                                  >
                                  Thanks,
                                  >
                                  TC
                                  >
                                  "kimiraikko nen" <kimiraikkone.. .@gmail.comwrot e in message
                                  >
                                  news:725ff39a-f310-49da-a447-a8bd6a563b3e@r6 6g2000hsg.googl egroups.com...
                                  On May 19, 1:10 pm, "TC" <getmyemai...@y ahoo.comwrote:
                                  >
                                  Hey Onur,
                                  >
                                  So you would recommend something like the following:
                                  >
                                  MyFunction(ByVa l encryptString as String) as String
                                  Try
                                  Using(MyCryptoS tream)
                                  ' Do Crypto tasks
                                  return MyEncryptedStri ng
                                  End Using
                                  Catch ex as CryptographicEx ception
                                  HandleCryptoExc eption ex
                                  Catch ex as Exception
                                  HandleException (ex)
                                  return Nothing
                                  Finally
                                  If Not MyMemoryStream Is Nothing Then
                                  MyMemoryStream. Close
                                  End If
                                  ' Do not close CryptoStream here as it causes duplicitous
                                  exception
                                  ' The 'Using' block will dispose of any CryptoStream resources
                                  End Function
                                  >
                                  The above does not cause the duplicitous exception to be thrown.
                                  >
                                  Thanks,
                                  >
                                  Todd
                                  >
                                  "kimiraikko nen" <kimiraikkone.. .@gmail.comwrot e in message
                                  >
                                  >news:e75b959 6-71bd-485e-863b-9fcc301312f6@a2 3g2000hsc.googl egroups.com....
                                  On May 18, 7:36 pm, "TC" <getmyemai...@y ahoo.comwrote:
                                  >
                                  Hey All,
                                  >
                                  I posted this to the Crypto users group and forgot to add the VB.Net
                                  users
                                  group. I apologize for any confusion.
                                  >
                                  I have been testing a try / catch / finally block and purposely raising
                                  exceptions and I've noticed that if an exception of "Length of the data
                                  to
                                  decrypt is invalid." is raised with the CryptoStream object, later this
                                  exception will get raised a second time and thrown to the caller when
                                  trying
                                  to close the stream in a Finally block.
                                  >
                                  For example:
                                  >
                                  Try
                                  ' Do tasks that cause CryptoStream to throw invalid length while
                                  decrypting
                                  >
                                  Catch ex as CryptographicEx ception
                                  ' Handle exception here
                                  Finally
                                  If Not MemStream is Nothing then
                                  ' No 2nd exception thrown here
                                  MemStream.Close ()
                                  End If
                                  >
                                  If Not CrypStream is Nothing then
                                  ' Exception thrown a 2nd time
                                  CrypStream.Clos e()
                                  End If
                                  >
                                  Has anyone else experienced the above?
                                  >
                                  If so, how to address the problem or is this a bug?
                                  >
                                  TC,
                                  Do you experience the same problem when you use "Using-End Using"
                                  statement instead of Try-Catch for CryptoStream object?
                                  >
                                  Thanks,
                                  >
                                  Onur Güzel- Hide quoted text -
                                  >
                                  - Show quoted text -
                                  >
                                  Hi,
                                  If it solves your problem, it's OK, however you can also try to put
                                  try-catch inside Using-End Using without "Finally" because "Using-End
                                  Using" does all the disposal operation:
                                  >
                                  MyFunction(ByVa l encryptString as String) as String
                                  >
                                  Using(MyCryptoS tream)
                                  Try
                                  ' Do Crypto tasks
                                  return MyEncryptedStri ng
                                  >
                                  Catch ex as CryptographicEx ception
                                  HandleCryptoExc eption ex
                                  ' The 'Using' block will dispose of any CryptoStream
                                  resources
                                  End Using
                                  End Function
                                  >
                                  Thanks,
                                  >
                                  Onur Güzel
                                  >
                                  TC,
                                  To make sure that all of your disposable resources are disposed
                                  clearly by Using statement, you can also use seperate "Using"s for
                                  each disposable object like:
                                  >
                                  Using block1 As New DisposableObjec t1
                                  'Statements here
                                  End Using
                                  >
                                  Using block2 As New DisposableObjec t2
                                  'Statements here
                                  End Using
                                  >
                                  and so on...
                                  >
                                  Better ideas may exist of course.
                                  >
                                  Thanks,
                                  >
                                  Onur Güzel
                                  However, as addition:
                                  I tried nesting "Using"s and seems to work in VB.NET also:

                                  Like:

                                  Using w1 As IO.StreamWriter = IO.File.CreateT ext("c:\foo1.tx t")
                                  ' code here
                                  w1.Write("foo1" )
                                  Using w2 As IO.StreamWriter = IO.File.CreateT ext("c:\foo2.tx t")
                                  w2.Write("foo2" )
                                  End Using
                                  End Using

                                  Thanks,

                                  Onur Güzel

                                    Comment

                                    • Jack Jackson
                                      #10
                                      Re: Finally block causing exception to throw twice with CryptoStream?

                                      In VB you can nest the Usings, or you can:

                                      Using obj1 As New SomeObj1, obj2 As New SomeObj2, obj3 As New SomeObj3
                                      ...
                                      End Using

                                      On Tue, 20 May 2008 09:35:49 -0400, "TC" <getmyemails2@y ahoo.com>
                                      wrote:
                                      >Hey Onur,
                                      >
                                      >Perhaps better said, in C#, one can do something like the following:
                                      >
                                      >Using (object1, object2, object 3)
                                      // Perform tasks
                                      >End Using
                                      >
                                      >Is there a syntax for something similar in VB.Net or does one have to nest
                                      >the 'Using' statements like this:
                                      >
                                      >Using (object1)
                                      Using(object2)
                                      // Perform tasks
                                      End Using
                                      >End Using
                                      >
                                      >Thanks,
                                      >
                                      >TC
                                      >
                                      >"kimiraikkonen " <kimiraikkonen8 5@gmail.comwrot e in message
                                      >news:725ff39 a-f310-49da-a447-a8bd6a563b3e@r6 6g2000hsg.googl egroups.com...
                                      >On May 19, 1:10 pm, "TC" <getmyemai...@y ahoo.comwrote:
                                      >Hey Onur,
                                      >>
                                      >So you would recommend something like the following:
                                      >>
                                      >MyFunction(ByV al encryptString as String) as String
                                      >Try
                                      >Using(MyCrypto Stream)
                                      >' Do Crypto tasks
                                      >return MyEncryptedStri ng
                                      >End Using
                                      >Catch ex as CryptographicEx ception
                                      >HandleCryptoEx ception ex
                                      >Catch ex as Exception
                                      >HandleExceptio n(ex)
                                      >return Nothing
                                      >Finally
                                      >If Not MyMemoryStream Is Nothing Then
                                      >MyMemoryStream .Close
                                      >End If
                                      >' Do not close CryptoStream here as it causes duplicitous
                                      >exception
                                      >' The 'Using' block will dispose of any CryptoStream resources
                                      >End Function
                                      >>
                                      >The above does not cause the duplicitous exception to be thrown.
                                      >>
                                      >Thanks,
                                      >>
                                      >Todd
                                      >>
                                      >"kimiraikkonen " <kimiraikkone.. .@gmail.comwrot e in message
                                      >>
                                      >news:e75b959 6-71bd-485e-863b-9fcc301312f6@a2 3g2000hsc.googl egroups.com...
                                      >On May 18, 7:36 pm, "TC" <getmyemai...@y ahoo.comwrote:
                                      >>
                                      >>
                                      >>
                                      >>
                                      >>
                                      Hey All,
                                      >>
                                      I posted this to the Crypto users group and forgot to add the VB.Net
                                      users
                                      group. I apologize for any confusion.
                                      >>
                                      I have been testing a try / catch / finally block and purposely raising
                                      exceptions and I've noticed that if an exception of "Length of the data
                                      to
                                      decrypt is invalid." is raised with the CryptoStream object, later this
                                      exception will get raised a second time and thrown to the caller when
                                      trying
                                      to close the stream in a Finally block.
                                      >>
                                      For example:
                                      >>
                                      Try
                                      ' Do tasks that cause CryptoStream to throw invalid length while
                                      decrypting
                                      >>
                                      Catch ex as CryptographicEx ception
                                      ' Handle exception here
                                      Finally
                                      If Not MemStream is Nothing then
                                      ' No 2nd exception thrown here
                                      MemStream.Close ()
                                      End If
                                      >>
                                      If Not CrypStream is Nothing then
                                      ' Exception thrown a 2nd time
                                      CrypStream.Clos e()
                                      End If
                                      >>
                                      Has anyone else experienced the above?
                                      >>
                                      If so, how to address the problem or is this a bug?
                                      >>
                                      >TC,
                                      >Do you experience the same problem when you use "Using-End Using"
                                      >statement instead of Try-Catch for CryptoStream object?
                                      >>
                                      >Thanks,
                                      >>
                                      >Onur Güzel- Hide quoted text -
                                      >>
                                      >- Show quoted text -
                                      >
                                      >Hi,
                                      >If it solves your problem, it's OK, however you can also try to put
                                      >try-catch inside Using-End Using without "Finally" because "Using-End
                                      >Using" does all the disposal operation:
                                      >
                                      >
                                      >MyFunction(ByV al encryptString as String) as String
                                      >
                                      >Using(MyCrypto Stream)
                                      Try
                                      ' Do Crypto tasks
                                      return MyEncryptedStri ng
                                      >
                                      Catch ex as CryptographicEx ception
                                      HandleCryptoExc eption ex
                                      ' The 'Using' block will dispose of any CryptoStream
                                      >resources
                                      End Using
                                      End Function
                                      >
                                      >
                                      >Thanks,
                                      >
                                      >Onur Güzel
                                      >

                                        Comment

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