NullReferenceException Class (System)

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This page is specific to

Microsoft Visual Studio 2005/.NET Framework 2.0

Other versions are also available for the following:

.NET Framework Class Library

NullReferenceException Class

The exception that is thrown when there is an attempt to dereference a null object reference.

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

Syntax

Visual Basic (Declaration)

<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public Class NullReferenceException
    Inherits SystemException

Visual Basic (Usage)

Dim instance As NullReferenceException

[SerializableAttribute] 
[ComVisibleAttribute(true)] 
public class NullReferenceException : SystemException

C++

[SerializableAttribute] 
[ComVisibleAttribute(true)] 
public ref class NullReferenceException : public SystemException

/** @attribute SerializableAttribute() */ 
/** @attribute ComVisibleAttribute(true) */ 
public class NullReferenceException extends SystemException

JScript

SerializableAttribute 
ComVisibleAttribute(true) 
public class NullReferenceException extends SystemException

Remarks

Note that applications throw the ArgumentNullException exception rather than the NullReferenceException exception discussed here.

The following Microsoft intermediate language (MSIL) instructions throw NullReferenceException :

callvirt
cpblk
cpobj
initblk
ldelem.<type>
ldelema
ldfld
ldflda
ldind.<type>
ldlen
stelem.<type>
stfld
stind.<type>
throw
unbox

NullReferenceException uses the HRESULT COR_E_NULLREFERENCE, which has the value 0x80004003.

For a list of initial property values for an instance of NullReferenceException, see the NullReferenceException constructors.

Inheritance Hierarchy

System.Object
   System.Exception
     System.SystemException
      System.NullReferenceException

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Platforms

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

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

Version Information