Returns the hash code for this instance.
Assembly: mscorlib (in mscorlib.dll)
The 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 method that more closely represents the concept of a hash code for the type.
Notes for the Windows Runtime
When you call the method on a Windows Runtime structure, it provides the default behavior for value types that don’t override . This is part of the support that the .NET Framework provides for the Windows Runtime (see .NET Framework Support for Windows Store Apps and Windows Runtime). Windows Runtime structures can’t override , even if they’re written with C# or Visual Basic, because they can’t have methods. (In addition, structures in the Windows Runtime itself don’t inherit ValueType.) However, they appear to have ToString, Equals, and methods when you use them in your C# or Visual Basic code, and the .NET Framework provides the default behavior for these methods.
The following example demonstrates how the 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 Else Return False End If End Function Public Overloads Function GetHashCode() As Integer Return m_Re.GetHashCode() ^ m_Im.GetHashCode() End Function End Structure
.NET FrameworkSupported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0
.NET Framework Client ProfileSupported in: 4, 3.5 SP1
Portable Class LibrarySupported in: Portable Class Library
.NET for Windows Store appsSupported in: Windows 8
.NET for Windows Phone appsSupported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.