title: how to send dropdownlist selectedvalue as postback argument in ASP.NET
body: <p>I have a server control that works with <code>IPostBackEventHandler</code>.</p>
  
  <p>And inside that control, I have a DropDownList.</p>
  
  <p>And this DropDownList should raise postback event with it's argument.</p>
  
  <pre><code>DropDownList _ddl = new DropDownList();
  _ddl.Attributes.Add(HtmlTextWriterAttribute.Onchange.ToString()
      , this.Page.ClientScript.GetPostBackEventReference(this, "this.value"));
  </code></pre>
  
  <p>What I am trying to do is to get the selected value of DropDownList on postback.</p>
  
  <pre><code>public void RaisePostBackEvent(string eventArgument)
  {
  }
  </code></pre>
  
  <p>When I receive from the RaisePostBackEvents, I only get "this.value". Not the selected value from DropDownList.</p>
  
  <p>How could I solve this problem?</p>