title: Azure function for user confirmation during Azure DevOps Pull Request
body: <p>This questions is related to the one <a href="https://stackoverflow.com/questions/59679053/pull-request-pop-up-a-confirmation-box/59709951#59709951">here</a></p>
  
  <p>I am trying to put up a dialog box to show the author at the time a pull request is created in my Azure DevOps service. This box should be shown in the author's browser window like so:</p>
  
  <p>Have you run System tests? 
    Yes
    Not applicable</p>
  
  <p>Here's the code I have at the moment, just trying to show a dummy Message Box</p>
  
  <pre><code>#r "Newtonsoft.Json"
  
  using System;
  using System.Net;
  using System.Net.Http;
  using System.Net.Http.Headers;
  using System.Text;
  using Newtonsoft.Json;
  using System.Windows;
  
  public static async Task&lt;HttpResponseMessage&gt; Run(HttpRequestMessage req, TraceWriter log)
  {
      try
      {
          log.Info("Service Hook Received.");
  
          // Get request body
          dynamic data = await req.Content.ReadAsAsync&lt;object&gt;();
  
          log.Info("Data Received: " + data.ToString());
  
          // Get the pull request object from the service hooks payload
          dynamic jObject = JsonConvert.DeserializeObject(data.ToString());
  
          // Get the pull request id
          int pullRequestId;
          if (!Int32.TryParse(jObject.resource.pullRequestId.ToString(), out pullRequestId))
          {
              log.Info("Failed to parse the pull request id from the service hooks payload.");
          };
  
          // Get the pull request title
          string pullRequestTitle = jObject.resource.title;
  
          log.Info("Service Hook Received for PR: " + pullRequestId + " " + pullRequestTitle);
  
          // Get the pull request text
          string checkinNotes = jObject.detailedMessage.text;
          log.Info("Checkin notes Received for PR: " + pullRequestId + " " + checkinNotes);
  
          MessageBox.Show("Have you run System Tests?");
  
          return req.CreateResponse(HttpStatusCode.OK);
      }
      catch (Exception ex)
      {
          log.Info(ex.ToString());
          return req.CreateResponse(HttpStatusCode.InternalServerError);
      }
  }
  </code></pre>
  
  <p>When, I compile this, I get the following error:</p>
  
  <pre><code>2020-01-13T09:09:03.664 [Error] run.csx(41,9): error CS0103: The name 'MessageBox' does not exist in the current context
  </code></pre>
  
  <p>How can I modify this Azure function achieve my goal?</p>