VB.NET等价于VB6 Attribute Item.VB_UserMemId = 0 [英] VB.NET equivalent of VB6 Attribute Item.VB_UserMemId = 0

问题描述

在VB6中，我有一个类<$>中定义的属性c $ c> MyScalars 如下：

 公共属性获取项目（vntIndexKey As Variant）As MyScalar 
属性Item.VB_UserMemId = 0 
设置项目= mCol（vntIndexKey）
 ... 
结束属性
  

这似乎使得在Excel VBA中，我可以访问此属性而不指定它（如同默认属性）：

  Dim oOut As Object 
 Set oOut = MyScalars（Range（E10）。Value）
  

VB.NET中是否有等效的属性？我已经尝试了以下内容，但它在VBA中出现错误：

 默认公共只读属性项（ByVal vntIndexKey As String）作为MyScalar 
获取
如果mCol.ContainsKey（vntIndexKey）然后
项目= mCol.Item（vntIndexKey）
结束如果
 ... 
结束属性
  

解决方案

Govert的回复是正确的。
COM IDispatch 界面的所有成员都会自动标记一个 DISPID 值，
当从.NET转换为COM时。此自动进程的唯一例外是值0，该值为该类的默认成员保留。如果您没有设置 dispid ，那么移植到COM的.NET类的默认成员是 :: ToString 方法。
在你的例子中：

  DispId（0）> _ 
公共ReadOnly属性项（ByVal vntIndexKey As String）As MyScalar 
 
结束属性
  

I've upgraded a class from VB6 to VB.NET to be used in Excel via COM.

In VB6, I have a property defined in class MyScalars as this:

Public Property Get Item(vntIndexKey As Variant) As MyScalar
Attribute Item.VB_UserMemId = 0
    Set Item = mCol(vntIndexKey)
    ...
End Property

This seems to make it so that in Excel VBA, I can access this property without specifying it (so like a default property):

Dim oOut As Object
Set oOut = MyScalars(Range("E10").Value)

Is there an equivalent attribute in VB.NET that does this? I've tried the following but it gives an error in the VBA:

Default Public ReadOnly Property Item(ByVal vntIndexKey As String) As MyScalar
    Get
        If mCol.ContainsKey(vntIndexKey) Then
            Item = mCol.Item(vntIndexKey)
        End If
        ...
End Property

解决方案

The reply of Govert is the right one. All the members of a COM IDispatch interface are automatically marked with a DISPID value, when converted from .NET to COM. The only exception for this automatic process is the value 0, which is reserved for the default member of the class. if you do not set the dispid, the default member of .NET classes when is ported to COM is the ::ToString method. In your example:

< DispId(0) > _
Public ReadOnly Property Item(ByVal vntIndexKey As String) As MyScalar

End Property 

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