title: C# Visual Studio 2015: IWebProxy certificate validation
body: <p>I'm trying to create a C# proxy DLL that allow VS2015 Community, on my offline workstation, access to internet through a corporate HTTP proxy with authentication.</p>
  
  <p>Following instruction of <a href="https://blogs.msdn.microsoft.com/rido/2010/05/06/how-to-connect-to-tfs-through-authenticated-web-proxy/" rel="noreferrer">this MSDN blog post</a>  I'm able to connect VisualStudio to HTTP pages in this way:</p>
  
  <pre><code>namespace VSProxy
  {
      public class AuthProxyModule : IWebProxy
      {   
          ICredentials crendential = new NetworkCredential("user", "password");
  
          public ICredentials Credentials
          {
              get
              {
                  return crendential;
              }
              set
              {
                  crendential = value;
              }
          }
  
          public Uri GetProxy(Uri destination)
          {
              ServicePointManager.ServerCertificateValidationCallback = (Header, Cer, Claim, SslPolicyErrors) =&gt; true;
              return new Uri("http://128.16.0.123:1234", UriKind.Absolute);
          }
  
          public bool IsBypassed(Uri host)
          {
              return host.IsLoopback;
          }
      }
  }
  </code></pre>
  
  <p>But I'm not able to connect to the account authentication page for Visual Studio Community access.</p>
  
  <p>So, I'm trying to validate Microsoft certificate using DLL.</p>
  
  <p>There is any way can I accomplish HTTPS and certificate issue?</p>
  
  <p>How can I validate the certificate in the webProxy DLL?</p>