title: Preventing duplicate strings in C#
body: <p>I have a string in my code which concatenates email addresses from various tables in the database and then shows up in outlook in the cc field.</p>
  
  <p>all i want is to filter the string so that the string does not contain any duplicate email address. in other words, i do not want a single email address to be repeated again in the output.</p>
  
  <p>please help</p>
  
  <pre><code>DataSet ds = DatabaseFunctions.getEmailsBySPROC("getEmailByCircuit", sql_CircuitEmail);
  
  if (ds != null)
  {
      for (int idx = 0; idx &lt; ds.Tables[0].Rows.Count; idx++)
      {
          emailList = emailList + ds.Tables[0].Rows[idx]["Email"].ToString() + ";";
      }
  }
  </code></pre>
  
  <p>thats the code to retireve from one table..</p>
  
  <p>there another code to retrive from another table..
  \and the string is email list seperated by ; semicolon</p>