title: Dropdown list selected index changed
body: <p>I did my drop down list that get its values from the database and when running the application, it did not work and the compiler did not see the code.</p>
  
  <p>// aspx</p>
  
  <pre><code>  &lt;asp:UpdatePanel ID="UpdatePanel3" runat="server"&gt;
                   &lt;ContentTemplate&gt;
                         &lt;asp:DropDownList ID="DDlProductFamily" runat="server"
                           ondatabound="DDlProductFamily_DataBound"
                           onselectedindexchanged="DDlProductFamily_SelectedIndexChanged"&gt;
                                                  &lt;/asp:DropDownList&gt;
                                              &lt;/ContentTemplate&gt;
                                              &lt;Triggers&gt;
                                                  &lt;asp:AsyncPostBackTrigger ControlID="DDlProductFamily" EventName="SelectedIndexChanged" /&gt;
                                              &lt;/Triggers&gt;
                                          &lt;/asp:UpdatePanel&gt;
  </code></pre>
  
  <p>// cs</p>
  
  <pre><code> protected void DDlProductFamily_SelectedIndexChanged(object sender, EventArgs e)
      {
          using (SqlConnection Con = Connection.GetConnection())
          {
              SqlCommand Com = new SqlCommand("SelectThumbByProductFamily", Con);
              Com.CommandType = CommandType.StoredProcedure;
              Com.Parameters.Add(Parameter.NewInt("@ProductCategory_Id",
                  DDlProductFamily.SelectedValue.ToString()));
              SqlDataAdapter DA = new SqlDataAdapter(Com);
              DA.Fill(dt);
              DataList1.DataSource = dt;
              DataList1.DataBind();
          }
      }
  </code></pre>