Question

以下代码让VS抱怨两件事：

IComparer界面必须实施Compare(...)
Implements...在方法/多行lambda（函数内）中无效。

那有什么问题呢？签名是正确的，使函数lambda oneliner没有帮助。它的语法与documentation中的语法相同：

Public Class ColorSorter : Implements Collections.IComparer
    Public Function Compare(x As Object, y As Object) As Integer
        Implements Collections.IComparer.Compare

        Dim cx As Drawing.Color, cy As Drawing.Color
        Dim hx As Single, hy As Single, sx As Single, sy As Single, bx As Single, by As Single

        cx = DirectCast(x, Drawing.SolidBrush).Color
        cy = DirectCast(y, Drawing.SolidBrush).Color
        sx = cx.GetSaturation()
        sy = cy.GetSaturation()
        hx = cx.GetHue()
        hy = cy.GetHue()
        bx = cx.GetBrightness()
        by = cy.GetBrightness()

        If hx < hy Then : Return -1
        ElseIf hx > hy Then : Return 1
        Else
            If sx < sy Then : Return -1
            ElseIf sx > sy Then : Return 1
            Else
                If bx < by Then : Return -1
                ElseIf bx > by Then : Return 1
                Else : Return 0
                End If
            End If
        End If
    End Function
End Class

Answer 1

在VB中没有语句终止符（如C＃中的;），因此每一行都是一个语句。这就是为什么你不能在像C＃这样的地方放置 New Line 。这就是为什么你的代码无法编译的原因。

将您的方法声明更改为一行：

Public Function Compare(x As Object, y As Object) As Integer  Implements Collections.IComparer.Compare

或者在第一行末尾添加_告诉编译器它不是语句的结尾，它应该在编译之前将它与下一行合并：

Public Function Compare(x As Object, y As Object) As Integer _
  Implements Collections.IComparer.Compare

Answer 2

尝试将其推入一行，或包含下划线字符：

Public Function Compare(x As Object, y As Object) As Integer _
    Implements Collections.IComparer.Compare

VB.Net不知道那两行没有下划线字符就连接了。

vb.net接口签名语法

2 个答案: