How can I prevent my program from running if it is not ran in Administrative mode? XP and Windows 7

Question

I have a C# Program that is supposed to be multi-OS compatible. It requires access to create a directory and get WMI Data, but that is only available if the program is ran as an Administrator. Otherwise, it fails.

Is there any command I can use to not run the program if it does not detect itself as being ran as an administrator? I tried adding a app.manifest and using "requireAdministrator", it prompts for login, but that appears to only work on Windows 7 and Vista, not XP.

Example:

 if (isAdmin==0)
 Console.WriteLine("Please run this as an administrator");
 exit;

Answer 1

Check if the User Is an Admin

public static bool IsAdministrator()
{
    WindowsIdentity windowsIdentity = WindowsIdentity.GetCurrent();
    WindowsPrincipal windowsPrincipal = new WindowsPrincipal(windowsIdentity);

    return windowsPrincipal.IsInRole(WindowsBuiltInRole.Administrator);
}

Restart the app if not an admin

public static bool RestartAsAdministrator(string filePath, string fileName, string errorCaption)
{
    Process process = null;
    ProcessStartInfo processStartInfo = new ProcessStartInfo();
    processStartInfo.FileName = Path.Combine(filePath, fileName);

    if (Environment.OSVersion.Version.Major >= 5) //5 is XP and 6 is Vista and 7
        processStartInfo.Verb = "runas";

    processStartInfo.Arguments = "";
    processStartInfo.WindowStyle = ProcessWindowStyle.Normal;
    processStartInfo.UseShellExecute = true;

    try
    {
        process = Process.Start(processStartInfo);
    }

    catch (Exception)
    {
        MessageBox.Show("Couldn't start as admin.\nPlease try manually by Right Clicking on " + Path.GetFileNameWithoutExtension(fileName) + " and selecting \"Run as administrator\"",
                            errorCaption + " Error", MessageBoxButton.OK, MessageBoxImage.Error);

        return false;
    }

    finally
    {
        if (process != null)
            process.Dispose();
    }

    return true;
}

Application Manifest File (Used to automatically Run as Admin)

<requestedExecutionLevel level="requireAdministrator" uiAccess="false" />

Answer 2

You can use this function to check if the current user (that starts your application) has administrator rights.

using System.Security.Principal;
...
bool IsAnAdministrator ()
{
   WindowsIdentity  identity = WindowsIdentity.GetCurrent();
   WindowsPrincipal principal = new WindowsPrincipal (identity);
   return principal.IsInRole(WindowsBuiltInRole.Administrator);
}

If you call this method and it returns false you can show a message and/or close your application.