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ValueType.GetHashCode Method

Returns the hash code for this instance.

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

Public Overrides Function GetHashCode As Integer

Return Value

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

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, and System.Collections.Hashtable.

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(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
         Return False
      End If
   End Function

   Public Overloads Function GetHashCode() As Integer
      Return m_Re.GetHashCode() ^ m_Im.GetHashCode()
   End Function

End Structure

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.