WebPermission.IsSubsetOf Method (IPermission)


Determines whether the current WebPermission is a subset of the specified object.

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

public override bool IsSubsetOf(
	IPermission target


Type: System.Security.IPermission

The WebPermission to compare to the current WebPermission.

Return Value

Type: System.Boolean

true if the current instance is a subset of the target parameter; otherwise, false. If the target is null, the method returns true for an empty current permission that is not unrestricted and false otherwise.

Exception Condition

The target parameter is not an instance of WebPermission.


The current instance contains a Regex-encoded right and there is not exactly the same right found in the target instance.

If the current WebPermission specifies a set of associated resources that is wholly contained by the target parameter, then the current WebPermission is a subset of target. This method overrides IsSubsetOf and is implemented to support the IPermission interface.

The following example uses IsSubsetOf to determine whether the access rights found in one instance of WebPermission are found in another instance of WebPermission.

// Create the target permission.
WebPermission targetPermission = new WebPermission();
targetPermission.AddPermission(NetworkAccess.Connect, new Regex("www\\.contoso\\.com/Public/.*"));

// Create the permission for a URI matching target.
WebPermission connectPermission = new WebPermission();
connectPermission.AddPermission(NetworkAccess.Connect, "www.contoso.com/Public/default.htm");

//The following statement prints true.
Console.WriteLine("Is the second URI a subset of the first one?: " + connectPermission.IsSubsetOf(targetPermission));

.NET Framework
Available since 1.1
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