How to Get Permissions Assign to Current Assembly in VS.NET 2005 Using C#
By Chetan Patel

Most of the time due to some security problem we are unable to continue with the application. So using this peace of code you can easily find out the permission level of the current assembly.

For that first we need to include the following name spaces in our Application

//For Application

using System; 
using System.Reflection; 
using System.Security; 
using System.Security.Policy; 
using System.Security.Permissions; 
using System.Collections; 

namespace permissionsAssigntoCurrentAssembly
{
    public partial class Form1 : Form
        {

            public Form1()

            {

                InitializeComponent();

            }

            // name of buildin namedpermissionset for fulltrust
            const string sFullTrust = "FullTrust";

            static PermissionSet finalSet = new NamedPermissionSet("FinalAssemblySet");
            static PermissionSet permSet = null;
            // is it assembly with fulltrust permissions?
            static bool fullTrust = true;
            private void Form1_Load(object sender, EventArgs e)
            {
                listBox1.Items.Add("List of permissions assign to current assembly");
                IEnumerator policy = SecurityManager.PolicyHierarchy();
                while (policy.MoveNext())
                {
                    PolicyLevel currentLevel = (PolicyLevel)policy.Current;
                    CodeGroup group = currentLevel.ResolveMatchingCodeGroups
                    (Assembly.GetExecutingAssembly().Evidence);
                    fullTrust &= ResGroups(group, currentLevel);
                    if (!fullTrust)
                    {
                       if (finalSet == null) finalSet = permSet;
                       else finalSet = finalSet.Intersect(permSet);
                       permSet = null;
                    }
                    else
                    {
                       listBox1.Items.Add("Current Level-" + currentLevel.Label + " || " + 
                       "Group--" + group.Name + " || " + "Group Policy--" + 
                       group.PermissionSetName);
                    }
                }
                if (fullTrust) MessageBox.Show("Assembly is running in full-trust mode.");
                else Output(finalSet,listBox1);
            }
            static bool ResGroups(CodeGroup parent, PolicyLevel pl)
            {
                NamedPermissionSet nps = pl.GetNamedPermissionSet(parent.PermissionSetName);
                if (isFullTrust(nps)) return true;
                if (permSet == null) permSet = (PermissionSet)nps
                else permSet = permSet.Union(nps);
                if (parent.Children.Count > 0)
                {
                   foreach (CodeGroup cp in parent.Children)
                   {
                      if (cp.Children.Count > 0) ResGroups(cp, pl);
                      else
                      {
                         NamedPermissionSet nps2 = pl.GetNamedPermissionSet
                         cp.PermissionSetName);
                         if (isFullTrust(nps2)) return true;
                         permSet = permSet.Union(nps2);
                      }
                   }
                }
                // fulltrust code group not found
                return false;
            }
            static bool isFullTrust(NamedPermissionSet nps)
            {
                if (nps.Name.Equals("FullTrust"))
                {
                    return true;

                }

                return false;
            }
            static void Output(PermissionSet ps,ListBox lst)
            {

                Enumerator psEnumerator = ps.GetEnumerator();
                while (psEnumerator.MoveNext())
                {
                     lst.Items.Add(psEnumerator.Current);
                }
            }
        }
}