title: on select change event - Html.DropDownListFor
body: <p>I have two dropdownlist. The selected value from the first one loads the other. How do I do that when I have the helper methods in a controller?</p>
  
  <pre><code>@using (Html.BeginForm())
  {
  &lt;div&gt;
      &lt;table width="100%" cellpadding="0" cellspacing="0"&gt;
          &lt;tr&gt;
              &lt;td&gt;&lt;b&gt;Select a District:&lt;/b&gt;&lt;/td&gt;
              &lt;td&gt;@Html.DropDownListFor(m =&gt; m.DistrictId, ViewData["DMManagers"] as IEnumerable&lt;SelectListItem&gt;, "Select One")&lt;/td&gt;
          &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td&gt;&lt;b&gt;Select a TM:&lt;/b&gt;&lt;/td&gt;
              &lt;td&gt;@Html.DropDownListFor(m =&gt; m.TMId, ViewData["TMManagers"] as IEnumerable&lt;SelectListItem&gt;, "Select One")&lt;/td&gt;
          &lt;/tr&gt;
      &lt;/table&gt;
  &lt;/div&gt;
  }
  
  private void LoadDistrictManagers()
  {
      var _DMS = (from c in SessionHandler.CurrentContext.ChannelGroups
                  join cgt in SessionHandler.CurrentContext.ChannelGroupTypes on c.ChannelGroupTypeId equals cgt.ChannelGroupTypeId
                  where cgt.Name == "District Manager"
                  select new { c.ChannelGroupId, c.Name }).OrderBy(m =&gt; m.Name);
      ViewData["DMManagers"] = new SelectList(_DMS, "ChannelGroupId", "Name");
  }
  
  private void LoadTerritoryManagers(int districtId)
  {
      var _TMS = (from c in SessionHandler.CurrentContext.ChannelGroups
                  join cgt in SessionHandler.CurrentContext.ChannelGroupTypes on c.ChannelGroupTypeId equals cgt.ChannelGroupTypeId
                  where cgt.Name == "Territory" &amp;&amp; c.ParentChannelGroupId == districtId
                  select new { c.ChannelGroupId, c.Name }).OrderBy(m =&gt; m.Name);
      ViewData["TMManagers"] = new SelectList(_TMS, "ChannelGroupId", "Name");
  }
  
  public ActionResult SummaryReport()
  {
      DistrictManagerModel model = new DistrictManagerModel();
      LoadDistrictManagers();
      return View("AreaManager", model);
  }
  </code></pre>