.NET Framework Standard Library Annotated Reference, Volume 1: Base Class Library and Extended Numerics Library

Example

using System;
using System.Security;
using System.Security.Permissions;

namespace Samples
{
  public class SecurityPermissionSample
  {
    public static void Main()
    {
      try
      {
        SecurityPermission sp =
          new SecurityPermission(
            SecurityPermissionFlag.Assertion);
        DoAssert();
        sp.Deny();
        DoAssert();
      }
      catch(Exception e)
      {
        Console.WriteLine("Exception: {0}", e);
      }
    }
    [SecurityPermissionAttribute(
      SecurityAction.Demand, Assertion=true)]
    public static void DoAssert()
    {
      EnvironmentPermission p =
             new EnvironmentPermission(
                     EnvironmentPermissionAccess.Read,
                     "USERNAME");
      p.Assert();
      Console.WriteLine("Assert succeeded");
    }
  }
}

The output is:

 Assert succeeded Exception: System.Security.SecurityException: Request failed. at System.Security.SecurityRuntime.FrameDescSetHelper(FrameSecurityDescriptor ...