GridTemplateColumns Dynamic Dropdowns

[Matt]

Hello,

I currently have a RadGrid with two GridTemplateColumns with dropdowns. When the first dropdown is changed I need the items in the second dropdown to change based on what was selected in the first. What is the best way to do this from the codebehind? I have the column section of my code shown below. Thanks in advance.
-------------------------------------------------------------------------------------------
 <telerik:GridTemplateColumn UniqueName="ClientName" HeaderText="Charge To">
                                <ItemTemplate>
                                    <%# Eval("ClientName")%>
                                </ItemTemplate>
                                <EditItemTemplate>
                                    <asp:DropDownList ID="ddlClient" runat="server" DataTextField="ClientName" DataValueField="ClientId"
                                        DataMember="ExpenseId" OnSelectedIndexChanged="ddlClient_SelectedIndexChanged">
                                    </asp:DropDownList>
                                </EditItemTemplate>
                            </telerik:GridTemplateColumn>
                            <telerik:GridTemplateColumn UniqueName="DepartmentName" HeaderText="Department" DataField="DepartmentId">
                                <ItemTemplate>
                                    <%# Eval("DepartmentName")%>
                                </ItemTemplate>
                                <EditItemTemplate>
                                    <asp:DropDownList ID="ddlDepartment" runat="server" DataTextField="DepartmentName"
                                        DataValueField="DepartmentId">
                                    </asp:DropDownList>
                                </EditItemTemplate>
                            </telerik:GridTemplateColumn>
-------------------------------------------------------------------------

[SamJ]

You can handle the SelectedIndexChanged event of the first drop down and there change the second drop down control. The below snippet can help you:

<telerik:GridTemplateColumn UniqueName="ClientName" HeaderText="Charge To">
    <ItemTemplate>
        <%# Eval("ClientName")%>
    </ItemTemplate>
    <EditItemTemplate>
        <asp:DropDownList AutoPostBack="true" ID="ddlClient" runat="server" DataTextField="ClientName" DataValueField="ClientId"
            DataMember="ExpenseId" OnSelectedIndexChanged="ddlClient_SelectedIndexChanged">
        </asp:DropDownList>
    </EditItemTemplate>
</telerik:GridTemplateColumn>
<telerik:GridTemplateColumn UniqueName="DepartmentName" HeaderText="Department" DataField="DepartmentId">
    <ItemTemplate>
        <%# Eval("DepartmentName")%>
    </ItemTemplate>
    <EditItemTemplate>
        <asp:DropDownList ID="ddlDepartment" runat="server" DataTextField="DepartmentName"
            DataValueField="DepartmentId">
        </asp:DropDownList>
    </EditItemTemplate>
</telerik:GridTemplateColumn>

protected void ddlClient_SelectedIndexChanged(object sender, EventArgs e)
{
    DropDownList ddlClient = sender as DropDownList;
    GridEditableItem editedItem = ddlClient.NamingContainer as GridDataItem;
    DropDownList ddlDepartment = editedItem["DepartmentName"].FindControl("ddlDepartment") as DropDownList;
}