title: How can I format a string?
body: <p>My string looks like 0145655789, I want to change its format to 0145.655.789</p>
  
  <p>This is the code I tried:</p>
  
  <p>enterpriseCode and aNum are both StringBuilder objects</p>
  
  <pre><code>enterpriseCode.Append(String.Format("{0:####.###.###}", aNum.ToString()).Replace(";", ""));
  </code></pre>
  
  <p>enterpriseCode still contains 0145655789 instead of 0145.655.789</p>