在VB中实现泛型IComparer [英] Implementing generic IComparer in VB

问题描述

我试图创建一个类来实现我自己的类Stellungen的通用IComparer（它翻译成位置，就像棋子或跳棋板上的那样）。

这是我得到的：

  Private Class comparer（Of Stellung）
实现System.Collections.Generic.IComparer （Of Stellung）
 
公共函数比较（x作为Stellung，y作为Stellung）作为整数实现System.Collections.Generic.IComparer（Of Stellung）.Compare 
 
 End Function 
 
 End Class 
  

问题是：函数内部我无法访问我班的任何领域。如果我从x开始。 Intellisense只会给我.Equals，.GetHashCode - 你在类型上获得的方法，但不在实例上。
Visual Studio 10也很重要，在函数的定义中，x作为Stellung和y作为Stellung是用浅蓝色书写的，这意味着它是一种类型而不是实际的对象。

那么...我该怎么做？我如何访问我想在课堂内比较的东西？
Thanks！

解决方案

这些字段可能是私人的，这就是您不能访问它们的原因。
让你的类实现 IComparable< T> 界面。您可以在比较器类中使用它。

这是一个通用比较器类的示例，它比较实现 IComparable< T> 的对象。

 公共类GenericComparer（Of T As IComparable（Of T））
继承Comparer（Of T）
 
 Public Overrides Function [Compare]（ByVal x As T，ByVal y As T）As Integer 
 If（Not x Is Nothing）Then 
 If（Not y Is Nothing）然后
返回x.CompareTo（y）
 End If 
返回1 
 End If 
 If（Not y Is Nothing）然后
返回-1 
 End如果
返回0 
 End Function 
 
公共覆盖函数等于（ByVal obj As Object）As Boolean 
 Dim comparer As GenericComparer（Of T）= TryCast（obj， GenericComparer（Of T））
返回（不是比较器是Nothing）
结束函数
 
公共覆盖函数GetHashCode（）A s Integer 
返回MyBase.GetType.Name.GetHashCode 
 End Function 
 
结束类
 
 
公共类Stellung 
实现IComparable（Of Stellung）
 
公共函数CompareTo（ByVal value As Stellung）As Integer 
'在这里您应该可以访问所有字段。 
 End Function 
 End class 
  

I am trying to create a class implementing the generic IComparer of my own class "Stellungen" (which translates to positions, like on a chess or checkers board).

This is what I got:

Private Class comparer(Of Stellung)
    Implements System.Collections.Generic.IComparer(Of Stellung)

    Public Function Compare(x As Stellung, y As Stellung) As Integer Implements System.Collections.Generic.IComparer(Of Stellung).Compare

    End Function

End Class

Problem is: inside the function I have no access to any fields of my class. If I start off with x. Intellisense will only give me .Equals, .GetHashCode - the methods you get on a type but not on an instance. Visual Studio 10 also highights this, in the definition of the function the bits "x as Stellung" and "y as Stellung" are written in light blue, meaning it is a type and not an actual object.

So... what do I do?? How do I access the things I want to compare inside my class?? Thanks!

解决方案

The fields are probably private and that is why you cant access them. Make you classes implement the IComparable<T> interface. You can than use that in you comparer class.
Here is an example of a generic comparer class that compares objects that implements IComparable<T>.

Public Class GenericComparer(Of T As IComparable(Of T))
    Inherits Comparer(Of T)

    Public Overrides Function [Compare](ByVal x As T, ByVal y As T) As Integer
        If (Not x Is Nothing) Then
            If (Not y Is Nothing) Then
                Return x.CompareTo(y)
            End If
            Return 1
        End If
        If (Not y Is Nothing) Then
            Return -1
        End If
        Return 0
    End Function

    Public Overrides Function Equals(ByVal obj As Object) As Boolean
        Dim comparer As GenericComparer(Of T) = TryCast(obj,GenericComparer(Of T))
        Return (Not comparer Is Nothing)
    End Function

    Public Overrides Function GetHashCode() As Integer
        Return MyBase.GetType.Name.GetHashCode
    End Function

End Class


public class Stellung
   Implements IComparable(Of Stellung)

   Public Function CompareTo(ByVal value As Stellung) As Integer
       'Here you should be able to access all fields. 
   End Function
End class

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