IEqualityComparer.GetHashCode(Object) 方法

定義

命名空間:

System.Collections

組件:

System.Runtime.dll

傳回指定物件的雜湊碼。

public:
 int GetHashCode(System::Object ^ obj);

public int GetHashCode (object obj);

abstract member GetHashCode : obj -> int

Public Function GetHashCode (obj As Object) As Integer

參數

obj

Object

要傳回雜湊碼的 Object。

傳回

Int32

指定物件的雜湊碼。

例外狀況

ArgumentNullException

obj 的型別是參考型別，而 obj 為 null。

範例

下列程式代碼範例示範不區分大小寫 IEqualityComparer的實作。 在此範例中，方法會 GetHashCode 傳回 型別所提供的 Object 哈希碼。

ref class myCultureComparer : IEqualityComparer
{
private:
    CaseInsensitiveComparer^ myComparer;

public:
    myCultureComparer()
    {
        myComparer = CaseInsensitiveComparer::DefaultInvariant;
    }

    myCultureComparer(CultureInfo^ myCulture)
    {
        myComparer = gcnew CaseInsensitiveComparer(myCulture);
    }

    virtual bool Equals(Object^ x, Object^ y) 
    {
        if (myComparer->Compare(x, y) == 0)
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    virtual int GetHashCode(Object^ obj)
    {
        return obj->ToString()->ToLower()->GetHashCode();
    }
};

class myCultureComparer : IEqualityComparer
{
    public CaseInsensitiveComparer myComparer;

    public myCultureComparer()
    {
        myComparer = CaseInsensitiveComparer.DefaultInvariant;
    }

    public myCultureComparer(CultureInfo myCulture)
    {
        myComparer = new CaseInsensitiveComparer(myCulture);
    }

    public new bool Equals(object x, object y)
    {
        return myComparer.Compare(x, y) == 0;
    }

    public int GetHashCode(object obj)
    {
        return obj.ToString().ToLower().GetHashCode();
    }
}

Public Class myCultureComparer
    Implements IEqualityComparer

    Dim myComparer As CaseInsensitiveComparer

    Public Sub New()
        myComparer = CaseInsensitiveComparer.DefaultInvariant
    End Sub

    Public Sub New(ByVal myCulture As CultureInfo)
        myComparer = New CaseInsensitiveComparer(myCulture)
    End Sub

    Public Function Equals1(ByVal x As Object, ByVal y As Object) _
        As Boolean Implements IEqualityComparer.Equals

        Return myComparer.Compare(x, y) = 0
    End Function

    Public Function GetHashCode1(ByVal obj As Object) _
        As Integer Implements IEqualityComparer.GetHashCode
        Return obj.ToString().ToLower().GetHashCode()
    End Function
End Class

備註

實作這個方法，為物件提供自定義哈希碼，對應至 方法所提供的 Equals 自定義相等比較。

給實施者的注意事項

實作必須確定如果 Equals(Object, Object) 方法針對兩個 對象x和 傳y回 true ，則的方法x所傳回的值必須等於 傳GetHashCode(Object)回的值y。

另請參閱

• GetHashCode()
• IHashCodeProvider