IEqualityComparer.GetHashCode(Object) 方法

定义

返回指定对象的哈希代码。Returns a hash code for the specified object.

public:
 int GetHashCode(System::Object ^ obj);
public int GetHashCode (object obj);
abstract member GetHashCode : obj -> int
Public Function GetHashCode (obj As Object) As Integer

参数

obj
Object

Object,将为其返回哈希代码。The Object for which a hash code is to be returned.

返回

指定对象的哈希代码。A hash code for the specified object.

异常

obj 的类型为引用类型,objnullThe type of obj is a reference type and obj is null.

示例

下面的代码示例演示如何实现不区分大小写的 IEqualityComparerThe following code example demonstrates the implementation of a case-insensitive IEqualityComparer. 在此示例中,GetHashCode 方法返回 Object 类型提供的哈希代码。In this example, the GetHashCode method returns the hash code provided by the Object type.

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

注解

实现此方法可为对象提供自定义的哈希代码,对应于 Equals 方法提供的自定义相等性比较。Implement this method to provide customized hash codes for objects,corresponding to the customized equality comparison provided by the Equals method.

实施者说明

若要确保 Equals(Object, Object) 方法返回 xy两个对象的 true,则需要实现,然后 GetHashCode(Object) x 方法返回的值必须等于为 y返回的值。Implementations are required to ensure that if the Equals(Object, Object) method returns true for two objects x and y, then the value returned by the GetHashCode(Object) method for x must equal the value returned for y.

适用于

另请参阅