When implemented by a derived class, determines whether the current permission is a subset of the specified permission.
Assembly: mscorlib (in mscorlib.dll)
- Type: System.Security.IPermission
A permission that is to be tested for the subset relationship. This permission must be of the same type as the current permission.
Return ValueType: System.Boolean
true if the current permission is a subset of the specified permission; otherwise, false.
The target parameter is not a null reference (Nothing in Visual Basic) and is not of the same type as the current permission.
The current permission is a subset of the specified permission if the current permission specifies a set of operations that is wholly contained by the specified permission. For example, a permission that represents access to C:\example.txt is a subset of a permission that represents access to C:\. If this method returns true, the current permission represents no more access to the protected resource than does the specified permission.
The following statements are required to be true for all overrides of the method. X, Y, and Z represent custom code access permission objects that are not null references, U represents an unrestricted code access permission, and N represents an empty permission with a PermissionState of None.
X.IsSubsetOf(X) returns true.
X.IsSubsetOf(Y) returns the same value as Y.IsSubsetOf(X) if and only if X and Y represent the same set of permissions.
If X.IsSubsetOf(Y) and Y.IsSubsetOf(Z) both return true, X.IsSubsetOf(Z) returns true.
X.IsSubsetOf(U) returns true.
X.IsSubsetOf(N) returns false.
N.IsSubsetOf(X) returns true.
If X and Y represent custom code access permission objects that are null references, X.IsSubsetOf(Y) returns true. If Z is also null, the compound set operation X.Union(Y).IsSubsetOf(Z) also returns true because the union of two null permissions is a null permission.Notes to Inheritors
You must override this method in a derived class.
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.