ValueType.GetHashCode Method

Returns the hash code for this instance.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

Syntax

'Declaration
<SecuritySafeCriticalAttribute> _
Public Overrides Function GetHashCode As Integer
[SecuritySafeCriticalAttribute]
public override int GetHashCode()

Return Value

Type: System.Int32
A 32-bit signed integer that is the hash code for this instance.

Remarks

The GetHashCode method applies to types derived from ValueType. One or more fields of the derived type is used to calculate the return value. 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. 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. 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.

For more information, see Object.GetHashCode.

Examples

The following example demonstrates how the GetHashCode method can be overridden by a derived value type.

Public Structure Complex
   Private m_Re As Double
   Private m_Im As Double

   Public Overloads Function Equals(ByVal 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
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();
   }
}

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

See Also

Reference