通过VB6中的COM处理在.NET类上公开的事件

Question

通过VB6中的COM处理在.NET类上公开的事件

我的测试.NET（在编译器设置中注册为interop的类库）代码：

Imports System.Runtime.InteropServices

<InterfaceType(ComInterfaceType.InterfaceIsIDispatch), ComVisible(True)> _
Public Interface MyEventInterface
    <DispId(1)> Event Exploded(ByVal Text As String)
    <DispId(2)> Sub PushRedButton()
End Interface


<ClassInterface(ClassInterfaceType.None)> _
Public Class EventTest
    Implements MyEventInterface

    Public Event Exploded(ByVal Text As String) Implements MyEventInterface.Exploded

    Public Sub PushRedButton() Implements MyEventInterface.PushRedButton

        RaiseEvent Exploded("Bang")

    End Sub

End Class

我的测试VB6应用程序winforms代码（引用了上面的类库）：

Public ct As New ComTest1.EventTest

Private Sub Command1_Click()

    ct.add_Exploded (ExplodedHandler)

    ct.PushRedButton

    ct.remove_Exploded (ExplodedHandler)

End Sub

Private Sub ExplodedHandler(ByVal Text As String)

    MsgBox Text

End Sub

具体来说，我不确定如何在VB6中设置处理程序，我得到的编译错误是VB6中此行上的“参数不可选”：

ct.add_Exploded (ExplodedHandler)

Answer 1

C＃

[ComVisible(true)] //Exposed
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)] //Our managed interface will be IDispatch
public interface IMathEvents
{

    void OnOperationCompleted(string message);

}
[ComVisible(true)]
[ClassInterface(ClassInterfaceType.None)]
[ComSourceInterfaces(typeof(IMathEvents))]  //Our event source is IMathEvents interface
[ComDefaultInterface(typeof(IMath))]
public class Math:IMath  /*IMath interface just declares a method named Add */
{
    public int Add(int x, int y)
    {
        if (null != this.OnOperationCompleted)
            this.OnOperationCompleted("Operation completed, result: " + (x+y).ToString());
        return x + y;
    }

    [ComVisible(false)]
    public delegate void OperationCompletedDel(string message); //No need to expose this delegate
    public event OperationCompletedDel OnOperationCompleted;

}
[ComVisible(true)]
public interface IMath
{
    int Add(int x, int y);
}

VB

私人WithEvents m作为数学

私人子Form_Load（）

 Set m = New PayClient.Math 

结束子

私有子m_OnOperationCompleted（ByVal文本为字符串）

 MsgBox Text 

结束子

私人子Command2_Click（）
m。加1、2

结束子

Answer 2

对.NET中的事件和VB6中的WithEvents使用<ComSourceInterfaces(GetType(接口名称))>

.NET类库：

Imports System.Runtime.InteropServices

' This interface is to expose the events
<Guid("28C7DCE1-90EF-4a30-AF7F-4187F9FFFDEB")> _
<InterfaceType(ComInterfaceType.InterfaceIsIDispatch)> _
Public Interface MathsEvents
    <DispId(1)> _
    Sub Calculated(ByVal Result As Double)
End Interface

' This interface is to expose the properties and methods
<Guid("86CE5E8D-777D-4cd5-8A7D-7F58737F1DB4")> _
<InterfaceType(ComInterfaceType.InterfaceIsIDispatch)> _
Public Interface _Maths
    <DispId(2)> _
    Property ValueA() As Double
    <DispId(3)> _
    Property ValueB() As Double
    <DispId(4)> _
    ReadOnly Property Result() As Double
    <DispId(5)> _
    Sub Add()
End Interface

' This is the actual class
' The events are exposed by using the ComSourceInterfaces attribute
' The properties and methods are exposed using the Implements keyword
<Guid("C58721B1-15B3-4eeb-9E1E-BCDA33D38EE6")> _
<ClassInterface(ClassInterfaceType.None)> _
<ComSourceInterfaces(GetType(MathsEvents))> _
Public Class Maths
    Implements _Maths
    Public Event Calculated(ByVal Result As Double)
    Private mValueA As Double
    Private mValueB As Double
    Private mResult As Double

    Public Property ValueA() As Double Implements _Maths.ValueA
        Get
            Return mValueA
        End Get
        Set(ByVal value As Double)
            mValueA = value
        End Set
    End Property

    Public Property ValueB() As Double Implements _Maths.ValueB
        Get
            Return mValueB
        End Get
        Set(ByVal value As Double)
            mValueB = value
        End Set
    End Property

    Public ReadOnly Property Result() As Double Implements _Maths.Result
        Get
            Return mResult
        End Get

    End Property

    Public Sub New()
        mValueA = 0
        mValueB = 0
        mResult = 0
    End Sub

    Public Sub Add() Implements _Maths.Add
        mResult = mValueA + mValueB
        RaiseEvent Calculated(mResult)
    End Sub

End Class

VB6测试应用程序：

Private WithEvents calc As Maths

Private Sub btnAdd_Click()

   calc.ValueA = CDbl(txtValueA.Text)
   calc.ValueB = CDbl(txtValueB.Text)
   calc.Add

End Sub

Private Sub calc_Calculated(ByVal Result As Double)
   txtResult.Text = CStr(Result)
End Sub

Private Sub Form_Load()

   Set calc = New Maths

End Sub