NullReferenceException Class (System)

NullReferenceException Class

.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

Visual C++

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

JScript

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 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

Version Information

.NET Framework

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

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Reference

NullReferenceException Members

System Namespace

Exception

Other Resources

Handling and Throwing Exceptions