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VB.NET Conversion problem when trying to convert from base class to subclass (BC30311: "Value of type <type1> cannot be converted to <type2> ")
原标题:

Please take a look at the following code:

Public Sub Method(Of TEntity As EntityObject)(ByVal entity As TEntity)
    If TypeOf entity Is Contact Then  
        Dim contact As Contact = entity  Compile error 
        Dim contact = DirectCast(entity, Contact)  Compile error  
        Dim contact = CType(entity, Contact)  Compile error 
    End If
End Sub

Any ideas?

最佳回答

Either one of the following works, I guess I will use the first one:

Dim contact As Contact = DirectCast(entity, Object) 
Dim contact As Contact = Convert.ChangeType(entity, TypeCode.Object)
问题回答

This should not give you a compile error and should properly cast it to the type you are looking for:

Dim contact As Contact = TryCast(entity, Contact) 




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