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XmlNamespaceManager.LookupPrefix Method

Finds the prefix declared for the given namespace URI.

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

public virtual string LookupPrefix(
	string uri


Type: System.String
The namespace to resolve for the prefix.

Return Value

Type: System.String
The matching prefix. If there is no mapped prefix, the method returns String.Empty. If a null value is supplied, then null is returned.



This method finds the mapped prefix by walking the stack (that is, it looks globally). The supplied string must be atomized for the lookup to succeed. In other words, the supplied string object must exist in the XmlNamespaceManager's NameTable.

The returned string is also atomized. For more information on atomized strings, see XmlNameTable.

The following example removes a namespace from the namespace manager.

String prefix = nsmgr.LookupPrefix("");
nsmgr.RemoveNamespace(prefix, "");

.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.