通过互操作将VB6对象传递给.NET对象？

Question

我有一个VB6应用程序,通过互操作显示.NET DLL表单.

我想在.NET DLL中的一个事件导致VB6应用程序中的表单显示.

我的想法是让VB6应用程序将表单的引用传递给.NET DLL.例如:

[VB6]
Dim objNetDllObject As New NetDllObject
objNetDllObject.PassVb6Form(MyForm)
objNetDllObject.ShowForm

[C#]
object Vb6Form; 
private void PassVb6Form(object form) { Vb6Form = form; }
private void button1_Click(object sender, EventArgs e) { Vb6Form.Show(); }

这会有用吗？

我在其他地方读过,在'过程边界'上发送对象可能会导致问题.它是否正确？

Answer 1

一种方法是在 .NET 中定义 COM 接口：

<System.Runtime.InteropServices.GuidAttribute("0896D946-8A8B-4E7D-9D0D-BB29A52B5D08"), _
InterfaceType(ComInterfaceType.InterfaceIsIDispatch)> _
Public Interface IEventHandler
    Sub OnEvent(ByRef sender As Object, ByRef e As Object)
End Interface

在VB6中实现该接口

Implements MyInterop.IEventHandler

Private Sub IEventHandler_OnEvent(ByRef sender As Variant, ByRef e As Variant)
    Dim id
    id = e.Entity.Id
    ' As long as e is COM Visible (not necessarily COM registered, this will work)
End Sub

然后在 .NET 中有一个带有 IEventHandler 静态集合的注册器：

<ComClass(ComRegistrar.ClassId, ComRegistrar.InterfaceId, ComRegistrar.EventsId>
Public Class ComRegistrar

   Private Shared ReadOnly _eventHandlers As New Dictionary(Of String, List(Of IEventHandler))


   ' This is called by .NET code to fire events to VB6
   Public Shared Sub FireEvent(ByVal eventName As String, ByVal sender As Object, ByVal e As Object)
        For Each eventHandler In _eventHandlers(eventName)
                eventHandler.OnEvent(sender, e)
        Next
   End Sub

   Public Sub RegisterHandler(ByVal eventName As String, ByVal handler As IEventHandler)
        Dim handlers as List(Of IEventHandler)
        If Not _eventHandlers.TryGetValue(eventName, handlers)
             handlers = New List(Of IEventHandler)
             _eventHandlers(eventName) = handlers
        End If
        handlers.Add(handler)
   End Sub

End Class

您的 .NET 代码将调用 FireEvent，如果 VB6 之前已调用 RegisterHandler，则您的 VB6 IEventHandler 将被调用。