vb.net - 即使定义了函数，我也必须在类中实现函数的错误

Question

这个问题在这里已经有了答案:





Class 'QueryParameterComparer' must implement Function Compare.

(2 个回答)


6年前关闭。




我收到错误:Class 'QueryParameterComparer' must implement 'Function Compare(x As QueryParameter, y As QueryParameter) As Integer' for interface 'System.Collections.Generic.IComparer(Of QueryParameter)'.
在这个类定义上:

    Protected Class QueryParameterComparer
        Implements IComparer(Of QueryParameter)

        Public Function Compare(x As QueryParameter, y As QueryParameter) As Integer
            If x.Name = y.Name Then
                Return String.Compare(x.Value, y.Value)
            Else
                Return String.Compare(x.Name, y.Name)
            End If
        End Function

    End Class

我也试着把它完整地写出来:

    Protected Class QueryParameterComparer
        Implements System.Collections.Generic.IComparer(Of QueryParameter)

        Public Function Compare(x As QueryParameter, y As QueryParameter) As Integer
            If x.Name = y.Name Then
                Return String.Compare(x.Value, y.Value)
            Else
                Return String.Compare(x.Name, y.Name)
            End If
        End Function

    End Class

我错过了什么？

Answer 1

与在 c# 中方法的名称必须与接口(interface)中的名称匹配的情况不同，在 VB.NET 中，所有接口(interface)实现必须始终使用 Implements 显式声明。每个成员的关键字:

Protected Class QueryParameterComparer
    Implements IComparer(Of QueryParameter)

    Public Function Compare(x As QueryParameter, y As QueryParameter) As Integer Implements IComparer(Of QueryParameter).Compare
        ' ...
    End Function
End Class