简化编码 trycast vb.net

Question

假设我有一些模型如下：黑色、绿色、蓝色、红色。

我有一个接收对象的函数，我想尝试将该对象转换为合适的模型。

现在我有了这样的代码：

Public Sub SetData(ByVal obj As Object)
    If TryCast(obj, black) IsNot Nothing Then
        Dim m As Black = TryCast(obj, black)
        ......
    ElseIf TryCast(obj, green) IsNot Nothing Then
        Dim m As green = TryCast(obj, green)
        ......
    ElseIf TryCast(obj, blue) IsNot Nothing Then
        Dim m As blue = TryCast(obj, blue)
        ......
    ElseIf TryCast(obj, red) IsNot Nothing Then
        Dim m As red = TryCast(obj, red)
        ......
    Else
        ......
    End If
End Sub

似乎代码效率不高，消耗更多内存，并使用更多 CPU 进行双重 trycast。如何简化这段代码，比如检查trycast，同时得到结果模型，而不需要双重trycast过程？

Answer 1

好吧，我会说 TryCast 没有意义，然后再 TryCasting 这样会更有效率：

Public Sub SetData(ByVal obj As Object)

    Dim blk As black = TryCast(obj, black)
    Dim grn As green = TryCast(obj, green)

    If blk IsNot Nothing Then

    ElseIf grn IsNot Nothing Then
        ......
    ElseIf 

    End If
End Sub

但我怀疑你应该在这里使用基础 class 或接口，然后你根本不需要转换它。

Answer 2

您可以使用 TypeOf 来了解您的对象 Class 是什么。示例

If TypeOf obj Is black Then
    Dim m As Black = TryCast(obj, black)
ElseIf TypeOf obj Is green Then
    Dim m As green = TryCast(obj, green)
ElseIf TypeOf obj Is blue Then
    Dim m As blue = TryCast(obj, blue)
ElseIf TypeOf obj Is red Then
    Dim m As red = TryCast(obj, red)
    ......
Else
    ......
End If

简化编码 trycast vb.net

Simplify coding trycast vb.net

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