title: String contains more than one word
body: <p>In my project I'm having a <code>StringBuilder</code> which takes the selected value of dropdown lists.  </p>
  
  <pre><code>StringBuilder builder = new StringBuilder();
  builder.Append(ddl_model.SelectedValue);
  builder.Append(ddl_language.SelectedValue);
  
  foreach (string str in list)
  {
      if (str.Contains(builder.ToString()))
      {
          lstpdfList.Items.Add(str);
      }
  }
  </code></pre>
  
  <p>It works with one value. I would like to make that I can check if contains two or more words.</p>
  
  <p>I have a file like PM12_Manual_Rev1_EN . Now I can find if it contains PM12. But there is a lot of them. So I would like to check if contains PM12 + EN.</p>