错误通过接口

Question

暴露事件中，我有这个接口

Interface IProDataSource 

    Delegate Sub DstartingHandler(ByVal sender As Object, ByVal e As EventArgs) 
    Event starting_Sinc As DstartingHandler 

End Interface 

尝试使用接口这样

Public Class DataSource : Implements IProDataSource 

    Public Event starting_Sinc As DstartingHandler Implements IProDataSource.starting_Sinc 
    Public Delegate Sub DstartingHandler(ByVal sender As Object, ByVal e As EventArgs) 

End Class 

给我的下一个错误

事件“starting_Sinc”无法实现 接口 'IProDataSource'事件'starting_Sinc'，因为它们的 代表类型'DstartingHandler'和 'IProDataSource.DstartingHandler'do 不匹配。

Answer 1

你需要移动的委托声明的接口外，申报公开。当实现它们的类是公共的时，接口使用的所有类型都必须是公共的。必要的或客户端代码永远不会分配事件。因此：

Public Delegate Sub DstartingHandler(ByVal sender As Object, ByVal e As EventArgs) 

Interface IProDataSource 
    Event starting_Sinc As DstartingHandler 
End Interface 

Public Class DataSource : Implements IProDataSource 
    Public Event starting_Sinc(ByVal sender As Object, ByVal e As System.EventArgs) Implements IProDataSource.starting_Sinc 
End Class 

如果限制类的可访问性，你可以使用你原来的做法：

Interface IProDataSource 
    Delegate Sub DstartingHandler(ByVal sender As Object, ByVal e As EventArgs) 
    Event starting_Sinc As DstartingHandler 
End Interface 

Friend Class DataSource : Implements IProDataSource 
    Public Event starting_Sinc(ByVal sender As Object, ByVal e As System.EventArgs) Implements IProDataSource.starting_Sinc 
End Class 

Answer 2

之所以您现在有2个代表在您的应用程序中定义的代表DstartingHandler的实例。一个在DataSource里面，另一个在IProDataSource里面。 DataSource中的那个似乎是一个错误，删除它应该可以解决所有的问题。

编辑

我尝试下面的代码并将其编译

Class C1 
    Implements IProDataSource 

    Public Event starting_Sinc(ByVal sender As Object, ByVal e As System.EventArgs) Implements IProDataSource.starting_Sinc 
End Class