title: ItextSharp - AutoFill a pdf form using C# - Issues with Checkboxes
body: <p>I am in the process of filling in a pdf form created using Acrobat pro with iTextSharp &amp; C#, and have found myself stuck when attempting to tick a checkbox field.</p>
  
  <p>I have it working for radio buttons and textboxes but cannot seem to get the checkbox working.
  I have also confirmed the checkbox name in this case "Q7b" is correct in the acrobat document and can find it on the form using the following code</p>
  
  <pre><code>private string getfieldnames(AcroFields fields)
  {
      StringBuilder sb = new StringBuilder();
  
      foreach (string key in fields.Fields.Keys)
      {
  
          sb.Append(key + Environment.NewLine);
      }
      return sb.ToString();
  
  }
  </code></pre>
  
  <p>The code I am using to update the checkbox is below</p>
  
  <pre><code>using (MemoryStream pdfFlat = new MemoryStream())
  {
  
      PdfReader pdfReader = new PdfReader(strPath);
      PdfStamper pdfStamp = new PdfStamper(pdfReader, pdfFlat);
      AcroFields fields = pdfStamp.AcroFields;
  
      //textfields
      fields.SetField("Initiating_Doctor", "Doctor A");
      fields.SetField("Speciality", "Surgeon");
  
      //Radiobuttons
      fields.SetField("PRELIM_Q1", "Yes");
      fields.SetField("PRELIM_Q2", "No");
      fields.SetField("PRELIM_Q3", "No");
      fields.SetField("PRELIM_Q4", "No");
  
      //checkbox - Set the checkbox to checked but this does not work.
      fields.SetField("Q7b", "Yes");
  
      pdfReader.Close();
      pdfStamp.FormFlattening = true;
      pdfStamp.FreeTextFlattening = true;
      pdfStamp.Writer.CloseStream = false;
      pdfStamp.Close();
  }
  </code></pre>
  
  <p>Any help would be greatly appreciated.</p>
  
  <p>Brad</p>