Question

I am trying to implement a simple filter from one dropdown box to another.

The second dropdown box deos not populate (with any item) when I select an item from the first dropdown.
I am not sure what I am missing.
Please advise.

Here is the ascx code:

  <div id="SubmitSection" style="width:auto; height:auto;" class="SubmitSectionStyle">
        <div id="DropdownSection" style="text-align:center;">
        <asp:DropDownList ID="DropDown1" runat="server" AppendDataBoundItems="true"
               onselectedindexchanged="Type_SelectedIndexChanged" ToolTip="Select Category">
              <asp:ListItem Text="--Select Category--" Value="" />
              <asp:ListItem Value="1">Department</asp:ListItem>
              <asp:ListItem Value="2">Safety</asp:ListItem>
        </asp:DropDownList>&nbsp;

        <asp:DropDownList ID="DropDown2" runat="server">
        <asp:ListItem Text="--Select One--" Value="" />
        </asp:DropDownList>

      </div>

And here is my code behind:

protected void Type_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (DropDown1.SelectedValue == "1")
        {
            DropDown2.Items.Clear();
            DropDown2.Items.Add("DeptTest");
            DropDown2.DataBind();
        }
        else if (DropDown1.SelectedValue == "2")
        {
            DropDown2.Items.Clear();
            DropDown2.Items.Add("SafetyTest");
            DropDown2.DataBind();
        }
    }

Answer 1

In your first dropdownlist, set AutoPostBack=”True”