Plzzzzzzzzzzz Help for callback function

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  • sajin
    #1

    Plzzzzzzzzzzz Help for callback function

    Hi All..

    We are using VB .Net 2005 for implementing an API. API needs to
    generate events. For this client wants us to use Windows Callback
    (delegate implementation) . The intention of using Windows Callback is
    to generalise our API so that it can be compatible with any other
    language e.g. C++.

    Using normal delegates will not help us since delegates is a VB.Net
    feature and any other language cant make a use of it. Could please
    someone suggest us how to write a Windows Callback function in VB.Net?

    Any help will be appreciated :)

    Regards
    -AlertAdmin

    Tags: None
    • Michel Posseth [MCP]
      #2
      Re: Plzzzzzzzzzzz Help for callback function

      Huh ???
      We are using VB .Net 2005 for implementing an API. API needs to
      generate events. For this client wants us to use Windows Callback
      (delegate implementation) . The intention of using Windows Callback is
      to generalise our API so that it can be compatible with any other
      language e.g. C++.
      >
      Using normal delegates will not help us since delegates is a VB.Net
      feature
      Delegates are a .Net framework feature there is nothing VB about using
      delegates

      http://msdn2.microsoft.com/en-us/library/17sde2xt.aspx


      However Classic event structures in VB

      Public event eMyEvent (byval justavalue as sting )

      raiseevent ("helloworld ")

      Is by the compiler translated to a delegate structure


      So if you want to comunicate with a event mechanism to legacy programs you
      can do 2 things

      1 comunicate with the event mechanism ( 1- way )
      2. comunicate over the idispatch interface ( 2- way event comunication
      possible in latebound way by just calling methods on Object pointers that
      are stored in property`s )

      Both would be easy to implement with a litle help of COM

      I wrote once a COM Server prog in VB.Net 2003 this way that needed to
      comunicate wit several VB6 , Delphi and a Clipper clients


      HTH

      michel







      "sajin" <sajin@iprlab.c omschreef in bericht
      news:1176126933 .695954.96050@b 75g2000hsg.goog legroups.com...
      Hi All..
      >
      We are using VB .Net 2005 for implementing an API. API needs to
      generate events. For this client wants us to use Windows Callback
      (delegate implementation) . The intention of using Windows Callback is
      to generalise our API so that it can be compatible with any other
      language e.g. C++.
      >
      Using normal delegates will not help us since delegates is a VB.Net
      feature and any other language cant make a use of it. Could please
      someone suggest us how to write a Windows Callback function in VB.Net?
      >
      Any help will be appreciated :)
      >
      Regards
      -AlertAdmin
      >

        Comment

        • sajin
          #3
          Re: Plzzzzzzzzzzz Help for callback function

          On Apr 10, 12:44 am, "Michel Posseth [MCP]" <msn...@posseth .com>
          wrote:
          Huh ???
          >
          We are using VB .Net 2005 for implementing an API. API needs to
          generate events. For this client wants us to use Windows Callback
          (delegate implementation) . The intention of using Windows Callback is
          to generalise our API so that it can be compatible with any other
          language e.g. C++.
          >
          Using normal delegates will not help us since delegates is a VB.Net
          feature
          >
          Delegates are a .Net framework feature there is nothing VB about using
          delegates
          >
          http://msdn2.microsoft.com/en-us/library/17sde2xt.aspx
          >
          However Classic event structures in VB
          >
          Public event eMyEvent (byval justavalue as sting )
          >
          raiseevent ("helloworld ")
          >
          Is by the compiler translated to a delegate structure
          >
          So if you want to comunicate with a event mechanism to legacy programs you
          can do 2 things
          >
          1 comunicate with the event mechanism ( 1- way )
          2. comunicate over the idispatch interface ( 2- way event comunication
          possible in latebound way by just calling methods on Object pointers that
          are stored in property`s )
          >
          Both would be easy to implement with a litle help of COM
          >
          I wrote once a COM Server prog in VB.Net 2003 this way that needed to
          comunicate wit several VB6 , Delphi and a Clipper clients
          >
          HTH
          >
          michel
          >
          "sajin" <s...@iprlab.co mschreef in berichtnews:117 6126933.695954. 96050@b75g2000h sg.googlegroups .com...
          >
          >
          >
          Hi All..
          >
          We are using VB .Net 2005 for implementing an API. API needs to
          generate events. For this client wants us to use Windows Callback
          (delegate implementation) . The intention of using Windows Callback is
          to generalise our API so that it can be compatible with any other
          language e.g. C++.
          >
          Using normal delegates will not help us since delegates is a VB.Net
          feature and any other language cant make a use of it. Could please
          someone suggest us how to write a Windows Callback function in VB.Net?
          >
          Any help will be appreciated :)
          >
          Regards
          -AlertAdmin- Hide quoted text -
          >
          - Show quoted text -

          Hi Mich,

          Thanks for your explanation. But we didnt get the point that you were
          trying to explain. To just clarify what we want; There are 2 parts of
          the project API and Add-in. Currently both are written in VB.Net. API
          fire events to Add-in and Add-in in turn needs to capture it and
          perform some function.
          Now, the firing events from API should be so general that if at a
          later point, Add-in is wriiten in C++ then also API should be able to
          fire the events. And this will be possible only if we use Windows
          Callback function. The Windows Callback function will be written in
          Add-in and it will be fired from the API. So, we are stuck at this
          point of how to use Windows Callback in VB.Net

          Can you please post the code or atleast the snippet of COM server
          prog. Or any other point that can help us would be of great help.


          Regards
          -AlertAdmin






            Comment

            • Michel Posseth [MCP]
              #4
              Re: Plzzzzzzzzzzz Help for callback function


              Well here is the link to a small COM example i once showed in this newsgroup

              Error 404 (Niet gevonden)!!1
              http://groups.google.nl/group/microsoft.public.dotnet.languages.vb/browse_thread/thread/b9974554b8d68a52/ca996d74d250974e?lnk=st&q=COM+Dll+VB.Net+Posseth&rnum=5&hl=nl#ca996d74d250974e



              you might want to look at this link to , to make sure we talk about the same
              thingy

              http://msdn2.microsoft.com/en-us/lib...f0(vs.80).aspx

              regards

              Michel




              "sajin" <sajin@iprlab.c omschreef in bericht
              news:1176189533 .308754.229650@ n76g2000hsh.goo glegroups.com.. .
              On Apr 10, 12:44 am, "Michel Posseth [MCP]" <msn...@posseth .com>
              wrote:
              >Huh ???
              >>
              We are using VB .Net 2005 for implementing an API. API needs to
              generate events. For this client wants us to use Windows Callback
              (delegate implementation) . The intention of using Windows Callback is
              to generalise our API so that it can be compatible with any other
              language e.g. C++.
              >>
              Using normal delegates will not help us since delegates is a VB.Net
              feature
              >>
              >Delegates are a .Net framework feature there is nothing VB about using
              >delegates
              >>
              >http://msdn2.microsoft.com/en-us/library/17sde2xt.aspx
              >>
              >However Classic event structures in VB
              >>
              >Public event eMyEvent (byval justavalue as sting )
              >>
              >raiseevent ("helloworld ")
              >>
              >Is by the compiler translated to a delegate structure
              >>
              >So if you want to comunicate with a event mechanism to legacy programs
              >you
              >can do 2 things
              >>
              >1 comunicate with the event mechanism ( 1- way )
              >2. comunicate over the idispatch interface ( 2- way event comunication
              >possible in latebound way by just calling methods on Object pointers that
              >are stored in property`s )
              >>
              >Both would be easy to implement with a litle help of COM
              >>
              >I wrote once a COM Server prog in VB.Net 2003 this way that needed to
              >comunicate wit several VB6 , Delphi and a Clipper clients
              >>
              >HTH
              >>
              >michel
              >>
              >"sajin" <s...@iprlab.co mschreef in
              >berichtnews:11 76126933.695954 .96050@b75g2000 hsg.googlegroup s.com...
              >>
              >>
              >>
              Hi All..
              >>
              We are using VB .Net 2005 for implementing an API. API needs to
              generate events. For this client wants us to use Windows Callback
              (delegate implementation) . The intention of using Windows Callback is
              to generalise our API so that it can be compatible with any other
              language e.g. C++.
              >>
              Using normal delegates will not help us since delegates is a VB.Net
              feature and any other language cant make a use of it. Could please
              someone suggest us how to write a Windows Callback function in VB.Net?
              >>
              Any help will be appreciated :)
              >>
              Regards
              -AlertAdmin- Hide quoted text -
              >>
              >- Show quoted text -
              >
              >
              Hi Mich,
              >
              Thanks for your explanation. But we didnt get the point that you were
              trying to explain. To just clarify what we want; There are 2 parts of
              the project API and Add-in. Currently both are written in VB.Net. API
              fire events to Add-in and Add-in in turn needs to capture it and
              perform some function.
              Now, the firing events from API should be so general that if at a
              later point, Add-in is wriiten in C++ then also API should be able to
              fire the events. And this will be possible only if we use Windows
              Callback function. The Windows Callback function will be written in
              Add-in and it will be fired from the API. So, we are stuck at this
              point of how to use Windows Callback in VB.Net
              >
              Can you please post the code or atleast the snippet of COM server
              prog. Or any other point that can help us would be of great help.
              >
              >
              Regards
              -AlertAdmin
              >
              >
              >
              >
              >
              >

                Comment

                • sajin
                  #5
                  Re: Plzzzzzzzzzzz Help for callback function

                  Hi Mich,

                  I am still bit confused, the scenario here is that lets say i have API
                  which is written in VB .net which will communicate with the Addin
                  (Office powerpoint addin). We need to generalize our API such that if
                  in future any addin which is written in other language also should be
                  able to communicate with our API.

                  So we thought of using delegates (Callback function)

                  This is what we have done
                  1. In API we have written the following

                  Public Delegate Sub InvokeDel()

                  Public Sub InvokeMethod(By Val a As Addin)
                  'Here Addin is the object of the OfficeAddin
                  Dim getDel As InvokeDel
                  getDel = AddressOf a.test
                  getDel.Invoke()
                  End Sub

                  2. In the addin lets say we have a method that has to be invoked
                  through the delegate

                  The following method we have written in Addin

                  Public Sub test()
                  MsgBox("I am in MyBaseClass called through delegates")
                  End Sub

                  3. Now in the addin we created an object of API and called the method
                  "InvokeMeth od" with the argument as object of addin

                  Dim obj As New Addin
                  Dim objApI As New API
                  objApI.InvokeMe thod(obj)
                  4.Here in this we have to have the reference of API in the addin as
                  well as Addin in API (since we have to get the method name of addin)

                  5. The above point is little confusing since it is cross referencing
                  the dll each other and our API will not be generalized.
                  6. Lets say if we have C++ addin , how we can do it...

                  If i am in wrong track, can you plzzz help me with this



                  Regards
                  -Sajin




                  On Apr 10, 10:59 pm, "Michel Posseth [MCP]" <M...@posseth.c omwrote:
                  Well here is the link to a small COM example i once showed in this newsgroup
                  >
                  http://groups.google.nl/group/micros...anguages.vb/br...
                  >
                  you might want to look at this link to , to make sure we talk about the same
                  thingy
                  >
                  http://msdn2.microsoft.com/en-us/lib...f0(vs.80).aspx
                  >
                  regards
                  >
                  Michel
                  >
                  "sajin" <s...@iprlab.co mschreef in berichtnews:117 6189533.308754. 229650@n76g2000 hsh.googlegroup s.com...
                  >
                  >
                  >
                  On Apr 10, 12:44 am, "Michel Posseth [MCP]" <msn...@posseth .com>
                  wrote:
                  Huh ???
                  >
                  We are using VB .Net 2005 for implementing an API. API needs to
                  generate events. For this client wants us to use Windows Callback
                  (delegate implementation) . The intention of using Windows Callback is
                  to generalise our API so that it can be compatible with any other
                  language e.g. C++.
                  >
                  Using normal delegates will not help us since delegates is a VB.Net
                  feature
                  >
                  Delegates are a .Net framework feature there is nothing VB about using
                  delegates
                  >
                  >http://msdn2.microsoft.com/en-us/library/17sde2xt.aspx
                  >
                  However Classic event structures in VB
                  >
                  Public event eMyEvent (byval justavalue as sting )
                  >
                  raiseevent ("helloworld ")
                  >
                  Is by the compiler translated to a delegate structure
                  >
                  So if you want to comunicate with a event mechanism to legacy programs
                  you
                  can do 2 things
                  >
                  1 comunicate with the event mechanism ( 1- way )
                  2. comunicate over the idispatch interface ( 2- way event comunication
                  possible in latebound way by just calling methods on Object pointers that
                  are stored in property`s )
                  >
                  Both would be easy to implement with a litle help of COM
                  >
                  I wrote once a COM Server prog in VB.Net 2003 this way that needed to
                  comunicate wit several VB6 , Delphi and a Clipper clients
                  >
                  HTH
                  >
                  michel
                  >
                  "sajin" <s...@iprlab.co mschreef in
                  berichtnews:117 6126933.695954. 96050@b75g2000h sg.googlegroups .com...
                  >
                  Hi All..
                  >
                  We are using VB .Net 2005 for implementing an API. API needs to
                  generate events. For this client wants us to use Windows Callback
                  (delegate implementation) . The intention of using Windows Callback is
                  to generalise our API so that it can be compatible with any other
                  language e.g. C++.
                  >
                  Using normal delegates will not help us since delegates is a VB.Net
                  feature and any other language cant make a use of it. Could please
                  someone suggest us how to write a Windows Callback function in VB.Net?
                  >
                  Any help will be appreciated :)
                  >
                  Regards
                  -AlertAdmin- Hide quoted text -
                  >
                  - Show quoted text -
                  >
                  Hi Mich,
                  >
                  Thanks for your explanation. But we didnt get the point that you were
                  trying to explain. To just clarify what we want; There are 2 parts of
                  the project API and Add-in. Currently both are written in VB.Net. API
                  fire events to Add-in and Add-in in turn needs to capture it and
                  perform some function.
                  Now, the firing events from API should be so general that if at a
                  later point, Add-in is wriiten in C++ then also API should be able to
                  fire the events. And this will be possible only if we use Windows
                  Callback function. The Windows Callback function will be written in
                  Add-in and it will be fired from the API. So, we are stuck at this
                  point of how to use Windows Callback in VB.Net
                  >
                  Can you please post the code or atleast the snippet of COM server
                  prog. Or any other point that can help us would be of great help.
                  >
                  Regards
                  -AlertAdmin- Hide quoted text -
                  >
                  - Show quoted text -

                    Comment

                    • Michel Posseth [MCP]
                      #6
                      Re: Plzzzzzzzzzzz Help for callback function

                      Hello Sajin

                      I would just write a COM interface , this wil make sure that your program is
                      capable of comunicating to .Net and legacy apps ( C++ , Delphi , VB6 etc
                      etc )
                      MS uses this with there complete Office line it is proven technology works
                      fine and verry easy to implement in anny .Net app
                      In this case you can invoke the methods directly or through an interface

                      In my opinion COM is the way to go in the by you described situation

                      regards

                      Michel



                      "sajin" <sajin@iprlab.c omschreef in bericht
                      news:1176294502 .896318.190500@ b75g2000hsg.goo glegroups.com.. .
                      Hi Mich,
                      >
                      I am still bit confused, the scenario here is that lets say i have API
                      which is written in VB .net which will communicate with the Addin
                      (Office powerpoint addin). We need to generalize our API such that if
                      in future any addin which is written in other language also should be
                      able to communicate with our API.
                      >
                      So we thought of using delegates (Callback function)
                      >
                      This is what we have done
                      1. In API we have written the following
                      >
                      Public Delegate Sub InvokeDel()
                      >
                      Public Sub InvokeMethod(By Val a As Addin)
                      'Here Addin is the object of the OfficeAddin
                      Dim getDel As InvokeDel
                      getDel = AddressOf a.test
                      getDel.Invoke()
                      End Sub
                      >
                      2. In the addin lets say we have a method that has to be invoked
                      through the delegate
                      >
                      The following method we have written in Addin
                      >
                      Public Sub test()
                      MsgBox("I am in MyBaseClass called through delegates")
                      End Sub
                      >
                      3. Now in the addin we created an object of API and called the method
                      "InvokeMeth od" with the argument as object of addin
                      >
                      Dim obj As New Addin
                      Dim objApI As New API
                      objApI.InvokeMe thod(obj)
                      4.Here in this we have to have the reference of API in the addin as
                      well as Addin in API (since we have to get the method name of addin)
                      >
                      5. The above point is little confusing since it is cross referencing
                      the dll each other and our API will not be generalized.
                      6. Lets say if we have C++ addin , how we can do it...
                      >
                      If i am in wrong track, can you plzzz help me with this
                      >
                      >
                      >
                      Regards
                      -Sajin
                      >
                      >
                      >
                      >
                      On Apr 10, 10:59 pm, "Michel Posseth [MCP]" <M...@posseth.c omwrote:
                      >Well here is the link to a small COM example i once showed in this
                      >newsgroup
                      >>
                      >http://groups.google.nl/group/micros...anguages.vb/br...
                      >>
                      >you might want to look at this link to , to make sure we talk about the
                      >same
                      >thingy
                      >>
                      >http://msdn2.microsoft.com/en-us/lib...f0(vs.80).aspx
                      >>
                      >regards
                      >>
                      >Michel
                      >>
                      >"sajin" <s...@iprlab.co mschreef in
                      >berichtnews:11 76189533.308754 .229650@n76g200 0hsh.googlegrou ps.com...
                      >>
                      >>
                      >>
                      On Apr 10, 12:44 am, "Michel Posseth [MCP]" <msn...@posseth .com>
                      wrote:
                      >Huh ???
                      >>
                      We are using VB .Net 2005 for implementing an API. API needs to
                      generate events. For this client wants us to use Windows Callback
                      (delegate implementation) . The intention of using Windows Callback
                      is
                      to generalise our API so that it can be compatible with any other
                      language e.g. C++.
                      >>
                      Using normal delegates will not help us since delegates is a VB.Net
                      feature
                      >>
                      >Delegates are a .Net framework feature there is nothing VB about
                      >using
                      >delegates
                      >>
                      >>http://msdn2.microsoft.com/en-us/library/17sde2xt.aspx
                      >>
                      >However Classic event structures in VB
                      >>
                      >Public event eMyEvent (byval justavalue as sting )
                      >>
                      >raiseevent ("helloworld ")
                      >>
                      >Is by the compiler translated to a delegate structure
                      >>
                      >So if you want to comunicate with a event mechanism to legacy programs
                      >you
                      >can do 2 things
                      >>
                      >1 comunicate with the event mechanism ( 1- way )
                      >2. comunicate over the idispatch interface ( 2- way event
                      >comunication
                      >possible in latebound way by just calling methods on Object pointers
                      >that
                      >are stored in property`s )
                      >>
                      >Both would be easy to implement with a litle help of COM
                      >>
                      >I wrote once a COM Server prog in VB.Net 2003 this way that needed
                      >to
                      >comunicate wit several VB6 , Delphi and a Clipper clients
                      >>
                      >HTH
                      >>
                      >michel
                      >>
                      >"sajin" <s...@iprlab.co mschreef in
                      >berichtnews:11 76126933.695954 .96050@b75g2000 hsg.googlegroup s.com...
                      >>
                      Hi All..
                      >>
                      We are using VB .Net 2005 for implementing an API. API needs to
                      generate events. For this client wants us to use Windows Callback
                      (delegate implementation) . The intention of using Windows Callback
                      is
                      to generalise our API so that it can be compatible with any other
                      language e.g. C++.
                      >>
                      Using normal delegates will not help us since delegates is a VB.Net
                      feature and any other language cant make a use of it. Could please
                      someone suggest us how to write a Windows Callback function in
                      VB.Net?
                      >>
                      Any help will be appreciated :)
                      >>
                      Regards
                      -AlertAdmin- Hide quoted text -
                      >>
                      >- Show quoted text -
                      >>
                      Hi Mich,
                      >>
                      Thanks for your explanation. But we didnt get the point that you were
                      trying to explain. To just clarify what we want; There are 2 parts of
                      the project API and Add-in. Currently both are written in VB.Net. API
                      fire events to Add-in and Add-in in turn needs to capture it and
                      perform some function.
                      Now, the firing events from API should be so general that if at a
                      later point, Add-in is wriiten in C++ then also API should be able to
                      fire the events. And this will be possible only if we use Windows
                      Callback function. The Windows Callback function will be written in
                      Add-in and it will be fired from the API. So, we are stuck at this
                      point of how to use Windows Callback in VB.Net
                      >>
                      Can you please post the code or atleast the snippet of COM server
                      prog. Or any other point that can help us would be of great help.
                      >>
                      Regards
                      -AlertAdmin- Hide quoted text -
                      >>
                      >- Show quoted text -
                      >
                      >

                        Comment

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