ValueType.GetHashCode ValueType.GetHashCode ValueType.GetHashCode ValueType.GetHashCode Method

定義

傳回這個執行個體的雜湊碼。Returns the hash code for this instance.

public:
 override int GetHashCode();
public override int GetHashCode ();
override this.GetHashCode : unit -> int
Public Overrides Function GetHashCode () As Integer

傳回

32 位元帶正負號的整數,其為這個執行個體的雜湊碼。A 32-bit signed integer that is the hash code for this instance.

範例

下列範例示範如何使用衍生的實值型別來覆寫 GetHashCode 方法。The following example demonstrates how the GetHashCode method can be overridden by a derived value type.

public ref struct Complex
{
public:
   double m_Re;
   double m_Im;
   virtual bool Equals( Object^ ob ) override
   {
      if ( dynamic_cast<Complex^>(ob) )
      {
         Complex^ c = dynamic_cast<Complex^>(ob);
         return m_Re == c->m_Re && m_Im == c->m_Im;
      }
      else
      {
         return false;
      }
   }

   virtual int GetHashCode() override
   {
      return m_Re.GetHashCode() ^ m_Im.GetHashCode();
   }
};
public struct Complex 
{
    public double m_Re;
    public double m_Im;

    public override bool Equals( object ob ){
        if( ob is Complex ) {
            Complex c = (Complex) ob;
            return m_Re==c.m_Re && m_Im==c.m_Im;
        }
        else {
            return false;
        }
    }

    public override int GetHashCode(){
        return m_Re.GetHashCode() ^ m_Im.GetHashCode();
    }
}
Public Structure Complex
   Private m_Re As Double
   Private m_Im As Double
       
   Public Overloads Function Equals(ob As Object) As Boolean
      If TypeOf ob Is Complex Then
         Dim c As Complex = CType(ob, Complex)
         Return m_Re = c.m_Re And m_Im = c.m_Im
      Else
         Return False
      End If
   End Function
   
   
   Public Overloads Function GetHashCode() As Integer
      Return m_Re.GetHashCode() ^ m_Im.GetHashCode()
   End Function

End Structure

備註

@No__t-0 方法適用于衍生自 ValueType 的類型。The GetHashCode method applies to types derived from ValueType. 衍生類型的一或多個欄位用來計算傳回值。One or more fields of the derived type is used to calculate the return value. 如果您呼叫衍生類型的 GetHashCode 方法,則傳回值不太可能適合當做雜湊表中的索引鍵使用。If you call the derived type's GetHashCode method, the return value is not likely to be suitable for use as a key in a hash table. 此外,如果其中一個或多個欄位的值變更,則傳回值可能會不適合當做雜湊表中的索引鍵使用。Additionally, if the value of one or more of those fields changes, the return value might become unsuitable for use as a key in a hash table. 不論是哪一種情況,請考慮撰寫您自己的 GetHashCode 方法,以更密切地表示該類型的雜湊碼概念。In either case, consider writing your own implementation of the GetHashCode method that more closely represents the concept of a hash code for the type.

如需詳細資訊,請參閱 Object.GetHashCodeSystem.Collections.HashtableFor more information, see Object.GetHashCode, and System.Collections.Hashtable.

@No__t 的注意事項-0Notes for the Windows 執行階段Windows Runtime

當您在 Windows 執行階段Windows Runtime 結構上呼叫 GetHashCode 方法時,它會為不會覆寫 GetHashCode 的實數值型別提供預設行為。When you call the GetHashCode method on a Windows 執行階段Windows Runtime structure, it provides the default behavior for value types that don't override GetHashCode. 這是 .NET Framework 提供給 Windows 執行階段Windows Runtime 的支援之一部分(請參閱Windows Store 應用程式和 Windows 執行階段的 .NET Framework 支援)。This is part of the support that the .NET Framework provides for the Windows 執行階段Windows Runtime (see .NET Framework Support for Windows Store Apps and Windows Runtime). Windows 執行階段Windows Runtime 結構不能覆寫 GetHashCode,即使它們是以C#或 Visual Basic 撰寫,因為它們不能有方法。structures can't override GetHashCode, even if they're written with C# or Visual Basic, because they can't have methods. (此外,Windows 執行階段Windows Runtime 本身的結構不會繼承 ValueType)。不過,當您在或 Visual Basic 程式C#代碼中使用它們時,它們似乎會有 ToStringEquals 和 @no__t 2 方法,而 .NET Framework 會提供這些方法的預設行為。(In addition, structures in the Windows 執行階段Windows Runtime itself don't inherit ValueType.) However, they appear to have ToString, Equals, and GetHashCode methods when you use them in your C# or Visual Basic code, and the .NET Framework provides the default behavior for these methods.

適用於