title: How can I check that the string only contains one specific character?
body: <pre><code>dr["DomainName"].ToString().Contains("*")
  </code></pre>
  
  <p>checks <code>dr["DomainName"]</code> contains the char <code>*</code>, but the condition may also be true if it contains other chars.</p>
  
  <p>How can I check that the string only contains one char and this char is a <code>*</code></p>