title: How to check if a user belongs to an AD group?
body: <p>At first I thought the code below works because if I have the group as "IT" it functions correctly because my username is in the IT group in active directory. What I learned is it always returns true whether I have my username in the IT group or not and if i change it to any other group I am in it returns always returns false. Any help would be appreciated.</p>
  
  <pre><code>    private void tabControl1_SelectedIndexChanged(object sender, EventArgs e)
      {
          // tab control security for admin tab
          bool admin = checkGroup("IT");
  
          if ((admin == true) &amp;&amp; (tabControl1.SelectedTab == tpHistory))
          {
              tabControl1.SelectedTab = tpHistory;
          }
          else if ((admin == false) &amp;&amp; (tabControl1.SelectedTab == tpHistory))
          {
              tabControl1.SelectedTab = tpRequests;
              MessageBox.Show("Unable to load tab. You have insufficient privileges.",
                  "Access Denied", MessageBoxButtons.OK, MessageBoxIcon.Stop);
          }
      }
  
      // check active directory to see if user is in Marketing department group
      private static bool checkGroup(string group)
      {
          WindowsIdentity identity = WindowsIdentity.GetCurrent();
          WindowsPrincipal principal = new WindowsPrincipal(identity);
          return principal.IsInRole(group);
      }
  </code></pre>