Invalid attempt to Read when reader is closed

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  • Chris
    #1

    Invalid attempt to Read when reader is closed

    Hi,

    i wrote this code for fetching data from a table using a stored procedure.
    The connection definition and opening are put in a class.
    The actual read of data occurs in code-behind.
    My problem with this code:

    Invalid attempt to Read when reader is closed at line: While dtreader.Read()

    Thanks for help
    Chris

    1) the class:
    -----------
    Public Class myclass
    Public Shared Function mydtreader() As SqlDataReader
    Dim dreader As SqlDataReader

    Try
    Using mConnection As New SqlConnection(p aram.Connection String)

    Dim mCom As SqlCommand = New SqlCommand("mys p", mConnection)
    mCom.CommandTyp e = CommandType.Sto redProcedure
    mConnection.Ope n()
    dreader = mCom.ExecuteRea der
    Return dreader
    End Using
    Catch ex As Exception
    Throw
    End Try
    End Function
    end class

    2) code-behind:
    ---------------
    Protected Sub pseudoSubmit_Cl ick(ByVal sender As Object, ByVal e As
    System.EventArg s) Handles pseudoSubmit.Cl ick
    Dim dtreader As SqlDataReader = chat.mydtreader
    While dtreader.Read()
    ......
    End While
    dtreader.Close( )
    End Sub


    Tags: None
    • =?Utf-8?B?S2VycnkgTW9vcm1hbg==?=
      #2
      RE: Invalid attempt to Read when reader is closed

      Chris,

      Your Using statement closes the connection. But a datareader needs the
      connection to be open so it can retrieve rows and deliver them to you in your
      While dtreader.Read() loop.

      You will need to keep the connection open until you are finished with the
      datareader. You might want to use:

      dreader = mCom.ExecuteRea der (CommandBehavio r.CloseConnecti on)

      so that when you eventually close the datareader the connection will get
      closed.

      Kerry Moorman


      "Chris" wrote:
      Hi,
      >
      i wrote this code for fetching data from a table using a stored procedure.
      The connection definition and opening are put in a class.
      The actual read of data occurs in code-behind.
      My problem with this code:
      >
      Invalid attempt to Read when reader is closed at line: While dtreader.Read()
      >
      Thanks for help
      Chris
      >
      1) the class:
      -----------
      Public Class myclass
      Public Shared Function mydtreader() As SqlDataReader
      Dim dreader As SqlDataReader
      >
      Try
      Using mConnection As New SqlConnection(p aram.Connection String)
      >
      Dim mCom As SqlCommand = New SqlCommand("mys p", mConnection)
      mCom.CommandTyp e = CommandType.Sto redProcedure
      mConnection.Ope n()
      dreader = mCom.ExecuteRea der
      Return dreader
      End Using
      Catch ex As Exception
      Throw
      End Try
      End Function
      end class
      >
      2) code-behind:
      ---------------
      Protected Sub pseudoSubmit_Cl ick(ByVal sender As Object, ByVal e As
      System.EventArg s) Handles pseudoSubmit.Cl ick
      Dim dtreader As SqlDataReader = chat.mydtreader
      While dtreader.Read()
      ......
      End While
      dtreader.Close( )
      End Sub
      >
      >
      >

        Comment

        • Chris
          #3
          Re: Invalid attempt to Read when reader is closed

          Thanks

          "Kerry Moorman" <KerryMoorman@d iscussions.micr osoft.comschree f in bericht
          news:6CBAAC4C-CE74-475D-B9AB-84B11F1873B0@mi crosoft.com...
          Chris,
          >
          Your Using statement closes the connection. But a datareader needs the
          connection to be open so it can retrieve rows and deliver them to you in
          your
          While dtreader.Read() loop.
          >
          You will need to keep the connection open until you are finished with the
          datareader. You might want to use:
          >
          dreader = mCom.ExecuteRea der (CommandBehavio r.CloseConnecti on)
          >
          so that when you eventually close the datareader the connection will get
          closed.
          >
          Kerry Moorman
          >
          >
          "Chris" wrote:
          >
          >Hi,
          >>
          >i wrote this code for fetching data from a table using a stored
          >procedure.
          >The connection definition and opening are put in a class.
          >The actual read of data occurs in code-behind.
          >My problem with this code:
          >>
          >Invalid attempt to Read when reader is closed at line: While
          >dtreader.Read( )
          >>
          >Thanks for help
          >Chris
          >>
          >1) the class:
          >-----------
          >Public Class myclass
          >Public Shared Function mydtreader() As SqlDataReader
          > Dim dreader As SqlDataReader
          >>
          > Try
          > Using mConnection As New
          >SqlConnection( param.Connectio nString)
          >>
          > Dim mCom As SqlCommand = New SqlCommand("mys p",
          >mConnection)
          > mCom.CommandTyp e = CommandType.Sto redProcedure
          > mConnection.Ope n()
          > dreader = mCom.ExecuteRea der
          > Return dreader
          > End Using
          > Catch ex As Exception
          > Throw
          > End Try
          > End Function
          >end class
          >>
          >2) code-behind:
          >---------------
          > Protected Sub pseudoSubmit_Cl ick(ByVal sender As Object, ByVal e As
          >System.EventAr gs) Handles pseudoSubmit.Cl ick
          > Dim dtreader As SqlDataReader = chat.mydtreader
          > While dtreader.Read()
          > ......
          > End While
          > dtreader.Close( )
          > End Sub
          >>
          >>
          >>

            Comment

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