title: Configure a TextFormField for date-format
body: <p>I put a empty TextFormField on a PDF. I want, that only a specific date format ("DD.MM.YY") can be filled in.</p>
  
  <p>I was looking for examples in the communitiy, but didn't find anything.</p>
  
  <pre><code>C#
  PdfTextFormField date1 = PdfTextFormField.CreateText(destPdf, new 
  Rectangle(200, 200, 60, 8), "_Date", "DD.MM.YY", fontHelvetica, 6);
  
  form.AddField(date1);
  </code></pre>
  
  <p>The goal is, that the field does not allow other formats (best would be, if also 34.10.2019 would be denied)</p>