错误：“地址”表达式无法转换为“整数”因为“整数”不是委托类型

Question

我在将 VB6 代码升级到 VB.NET 时遇到错误。错误发生在 WindowProc的地址

AddressOf 表达式无法转换为“Integer”，因为“Integer”不是委托类型

我对 SetWindowLong 的声明是：

Declare Function SetWindowLong Lib "user32"  Alias "SetWindowLongA"(
                    ByVal hWnd As Integer, 
                    ByVal nIndex As Integer, 
                    ByVal dwNewLong As Integer) As Integer

variables:

Dim GWL_WNDPROC As Short = -4  
Dim hWnd As Integer

Code for WindowProc :

Function WindowProc(ByVal hw As Integer, ByVal uMsg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer

    Dim x As Integer
    Dim a As String
    Dim wp As Short
    Dim temp As Object
    Dim ReadBuffer(1000) As Byte
    'Debug.Print uMsg, wParam, lParam
    Select Case uMsg
        Case 1025
            Debug.Print(VB6.TabLayout(uMsg, wParam, lParam))
            Debug.Print(uMsg & "  " & wParam & "  " & lParam)

            e_err = WSAGetAsyncError(lParam)
            e_errstr = GetWSAErrorString(e_err)

            If e_err <> 0 Then
                Debug.Print("Error String returned -> " & e_err & " - " & e_errstr)
                Debug.Print("Terminating....")
                do_cancel = True
                'Exit Function
            End If
            Select Case lParam
                Case FD_READ 'lets check for data
                    x = recv(mysock, ReadBuffer(0), 1000, 0) 'try to get some
                    If x > 0 Then 'was there any?
                        'UPGRADE_ISSUE: Constant vbUnicode was not upgraded. Click for more: 'ms-help://MS.VSCC.v90/dv_commoner/local/redirect.htm?keyword="55B59875-9A95-4B71-9D6A-7C294BF7139D"'
                        'default
                        'a = StrConv(System.Text.UnicodeEncoding.Unicode.GetString(ReadBuffer), vbUnicode) 'yep, lets change it to stuff we can understand
                        a = System.Text.UnicodeEncoding.Unicode.GetString(ReadBuffer) 'yep, lets change it to stuff we can understand

                        Debug.Print(a)
                        rtncode = Val(Mid(a, 1, 3))
                        'Debug.Print "Analysing code " & rtncode & "..."
                        Select Case rtncode
                            Case 354, 250

                                Progress = Progress + 1

                                Debug.Print(">>Progress becomes " & Progress)
                            Case 220
                                Debug.Print("Recieved Greenlight")
                                Green_Light = True
                            Case 221

                                Progress = Progress + 1

                                Debug.Print(">>Progress becomes " & Progress)
                            Case 550, 551, 552, 553, 554, 451, 452, 500
                                Debug.Print("There was some error at the server side")
                                Debug.Print("error code is " & rtncode)
                                do_cancel = True
                        End Select
                    End If
                Case FD_CONNECT 'did we connect?
                    mysock = wParam 'yep, we did! yayay
                    'Debug.Print WSAGetAsyncError(lParam) & "error code"
                    'Debug.Print mysock & " - Mysocket Value"

                Case FD_CLOSE 'uh oh. they closed the connection
                    Call closesocket(wp) 'so we need to close
            End Select
    End Select
    'let the msg get through to the form
    WindowProc = CallWindowProc(lpPrevWndProc, hw, uMsg, wParam, lParam)
End Function

我收到错误的原因是什么？我该如何解决这个问题？

Answer 1

您是否考虑过覆盖表单的WndProc 方法？重写过程中可能需要做更多的工作，但您最终会得到更好的代码。上一个链接中的示例：

Protected Overrides Sub WndProc(ByRef m As Message)
        ' Listen for operating system messages
        Select Case (m.Msg)
            ' The WM_ACTIVATEAPP message occurs when the application
            ' becomes the active application or becomes inactive.
        Case WM_ACTIVATEAPP

                ' The WParam value identifies what is occurring.
                appActive = (m.WParam.ToInt32() <> 0)

                ' Invalidate to get new text painted.
                Me.Invalidate()

        End Select
        MyBase.WndProc(m)
    End Sub

您可能还想查看 System.Net.Sockets 命名空间，用于适当替换当前套接字代码。

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我还找到了一篇文章 ".NET Makes窗口子类化简单”，例如，如果您不拥有要子类化的窗口，这可能会很有用。不管怎样，不推荐的一种方法是尝试使用 SetWindowLong 覆盖 Window Proc