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AppDomain.SetPrincipalPolicy Method

Specifies how principal and identity objects should be attached to a thread if the thread attempts to bind to a principal while executing in this application domain.

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

[SecurityPermissionAttribute(SecurityAction.Demand, Flags = SecurityPermissionFlag.ControlPrincipal)]
public void SetPrincipalPolicy(
	PrincipalPolicy policy


Type: System.Security.Principal.PrincipalPolicy

One of the PrincipalPolicy values that specifies the type of the principal object to attach to threads.




The operation is attempted on an unloaded application domain.

Setting this value will only be effective if you set it before using the Thread.CurrentPrincipal property. For example, if you set Thread.CurrentPrincipal to a given principal (for example, a generic principal) and then use the SetPrincipalPolicy method to set the PrincipalPolicy to WindowsPrincipal, the current principal will remain the generic principal.

The following example shows the effect on threads of using the SetPrincipalPolicy method to change the principal policy of the application domain. It also shows the effect of using the SetThreadPrincipal method to change the principal that is available for attaching to threads in the application domain.

using System;
using System.Security.Principal;
using System.Threading;

class ADPrincipal
	static void Main(string[] args)
		// Create a new thread with a generic principal.
		Thread t = new Thread(new ThreadStart(PrintPrincipalInformation));

		// Set the principal policy to WindowsPrincipal.
		AppDomain currentDomain = AppDomain.CurrentDomain;
		// The new thread will have a Windows principal representing the 
		// current user.
		t = new Thread(new ThreadStart(PrintPrincipalInformation));

		// Create a principal to use for new threads.
		IIdentity identity = new GenericIdentity("NewUser");
		IPrincipal principal = new GenericPrincipal(identity, null);
		// Create a new thread with the principal created above.
		t = new Thread(new ThreadStart(PrintPrincipalInformation));
		// Wait for user input before terminating.

	static void PrintPrincipalInformation()
		IPrincipal curPrincipal = Thread.CurrentPrincipal;
		if(curPrincipal != null)
			Console.WriteLine("Type: " + curPrincipal.GetType().Name);
			Console.WriteLine("Name: " + curPrincipal.Identity.Name);
			Console.WriteLine("Authenticated: " +

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

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.

.NET Framework

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