// To use the custom trust manager MyTrustManager, compile it into CustomTrustManager.dll, 
// place that assembly in the GAC, and  put the following elements in
// an ApplicationTrust.config file in the config folder in the Microsoft .NET framework
// installation folder.

//<?xml version="1.0" encoding="utf-8" ?>
//                    <ApplicationEntries />
//                    <IApplicationTrustManager class="MyNamespace.MyTrustManager, CustomTrustManager, Version=1.0.0.3, Culture=neutral, PublicKeyToken=5659fc598c2a503e"/>

using System;
using System.Security;
using System.Security.Policy;
using System.Windows.Forms;
namespace MyNamespace
{
    public class MyTrustManager : IApplicationTrustManager
    {
        public ApplicationTrust DetermineApplicationTrust(ActivationContext appContext, TrustManagerContext context)
        {
            ApplicationTrust trust = new ApplicationTrust(appContext.Identity);
            trust.IsApplicationTrustedToRun = false;

            ApplicationSecurityInfo asi = new ApplicationSecurityInfo(appContext);
            trust.DefaultGrantSet = new PolicyStatement(asi.DefaultRequestSet, PolicyStatementAttribute.Nothing);
            if (context.UIContext == TrustManagerUIContext.Run)
            {
                string message = "Do you want to run " + asi.ApplicationId.Name + " ?";
                string caption = "MyTrustManager";
                MessageBoxButtons buttons = MessageBoxButtons.YesNo;
                DialogResult result;

                // Displays the MessageBox.

                result = MessageBox.Show(message, caption, buttons);

                if (result == DialogResult.Yes)
                {
                    trust.IsApplicationTrustedToRun = true;
                    if (context != null)
                        trust.Persist = context.Persist;
                    else
                        trust.Persist = false;
                }
            }

            return trust;
        }

        public SecurityElement ToXml()
        {
            SecurityElement se = new SecurityElement("IApplicationTrustManager");
            se.AddAttribute("class", typeof(MyTrustManager).AssemblyQualifiedName);
            return se;
        }

        public void FromXml(SecurityElement se)
        {
            if (se.Tag != "IApplicationTrustManager" || (string)se.Attributes["class"] != typeof(MyTrustManager).AssemblyQualifiedName)
                throw new ArgumentException("Invalid tag");
        }
    }
}