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UrlIdentityPermission.Union Method

Creates a permission that is the union of the current permission and the specified permission.

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

public override IPermission Union (
	IPermission target
)
public IPermission Union (
	IPermission target
)
public override function Union (
	target : IPermission
) : IPermission
Not applicable.

Parameters

target

A permission to combine with the current permission. It must be of the same type as the current permission.

Return Value

A new permission that represents the union of the current permission and the specified permission.

Exception typeCondition

ArgumentException

The target parameter is not a null reference (Nothing in Visual Basic) and is not of the same type as the current permission.

-or-

The Url property is not a valid URL.

-or-

The two permissions are not equal and one is not a subset of the other.

The result of a call to the Union method is a permission that represents access to the URL as represented by the current permission, as well as access to the URL as represented by the specified permission.

The UrlIdentityPermission class supports set operations IsSubsetOf, Intersect, and Union) only when the current permission is equal to the specified permission, or when one of the permissions uses the wildcard operator ("*") and one is a subset of the other.

The following code example shows the behavior of the Union method. This example is part of a larger example provided for UrlIdentityPermission class.

NoteNote:

The code example is intended to show the behavior of the method, not to demonstrate its use. In general, the methods of permission classes are used by the security infrastructure; they are not typically used in applications.

// Union creates a new permission that is the union of the current permission
// and the specified permission.
private static void UnionDemo()
{
    UrlIdentityPermission permIdPerm1 = new UrlIdentityPermission("http://www.fourthcoffee.com/process/");
    UrlIdentityPermission permIdPerm2 = new UrlIdentityPermission("http://www.fourthcoffee.com/*");
    UrlIdentityPermission p3 = (UrlIdentityPermission)permIdPerm1.Union(permIdPerm2);
    try
    {
        if (p3 != null)
        {
            Console.WriteLine("The union of " + permIdPerm1.Url +
                " and \n\t" + permIdPerm2.Url + " is \n\t"
                + p3.Url + "\n");

        }
        else
        {
            Console.WriteLine("The union of " + permIdPerm1.Url +
                " and \n\t" + permIdPerm2.Url + " is null.\n");
        }
    }
    catch (SystemException e)
    {
        Console.WriteLine("The union of " + permIdPerm1.Url +
                " and \n\t" + permIdPerm2.Url + " failed.");

        Console.WriteLine(e.Message);
    }

}

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0
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