title: Cascading DropDownList in a DetailsView
body: <p>I have two dropdown within a DetailsView and I want to work in cascade, the idea is that an area contains various issues and these issues depend on the selected area, but I get the following error:</p>
  
  <p><strong>Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control.</strong></p>
  
  <p>in the next line:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;asp:DropDownList ID="ddlIssue" runat="server"
      DataTextField="NameIssue" DataValueField="IdIssue" 
  </code></pre>
  
  <p>The complete code is:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;asp:TemplateField HeaderText="Area" SortExpression="IdArea"&gt;
  &lt;EditItemTemplate&gt; 
    &lt;asp:DropDownList ID="ddlArea" runat="server"
        DataSourceID="SqlDataSource145711" DataTextField="NameArea"
        DataValueField="IdArea" AutoPostBack="true"
        AppendDataBoundItems="true" SelectedValue='&lt;%# Bind("IdArea") %&gt;'&gt; 
    &lt;/asp:DropDownList&gt;
    &lt;asp:SqlDataSource ID="SqlDataSource145711" runat="server"
      ConnectionString="&lt;%$ ConnectionStrings:BaseDatosCJConnectionString %&gt;"
      SelectCommand="SELECT IdArea, NameArea FROM AREA"&gt;
    &lt;/asp:SqlDataSource&gt;
  &lt;/EditItemTemplate&gt;
  &lt;ItemTemplate&gt;
    &lt;asp:Label ID="Label5" runat="server"
      Text='&lt;%# Bind("IdArea") %&gt;'&gt;&lt;/asp:Label&gt;
  &lt;/ItemTemplate&gt;
  &lt;/asp:TemplateField&gt;
  
  &lt;asp:TemplateField HeaderText="Issue"&gt;       
  &lt;EditItemTemplate&gt;
  **&lt;asp:DropDownList ID="ddlIssue" runat="server"
      DataTextField="NameIssue" DataValueField="IdIssue"**
      DataSourceID="SqlDataSource22" SelectedValue='&lt;%# Bind("IdIssue") %&gt;'
  &lt;/asp:DropDownList&gt;
  &lt;asp:SqlDataSource runat="server"
    ID="sqlDataSource22"
    ConnectionString="&lt;%$ ConnectionStrings:BaseDatosCJConnectionString %&gt;"
    SelectCommand="SELECT IdIssue, NameAIssue, IdArea FROM ISSUE"
    FilterExpression="IdArea = '{0}'"&gt;
    &lt;FilterParameters&gt;
    &lt;asp:ControlParameter Name="Param" ControlID="ddlArea"
      PropertyName="SelectedValue" /&gt;
    &lt;/FilterParameters&gt;                       
  &lt;/asp:SqlDataSource&gt;
  
  &lt;/EditItemTemplate&gt;
  &lt;/asp:TemplateField&gt;  
  </code></pre>
  
  <p>Can you help with the solution to this error?</p>
  
  <p>I have to do something from the code?</p>
  
  <p>blessings</p>