Can someone help me with populating one dropdownlist from another dropdownlist to filter the data? I tried using a scriptmanager but encountered an error:
The control with ID '' requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it.
This is my code:
<td>School</td>
<td>
<asp:ScriptManager ID="ScriptManager1" runat="server" />
<asp:DropDownList ID="SchoolRegister" runat="server" AutoPostBack="True"
DataSourceID="SqlDataSource1" DataTextField="SchoolName" DataValueField="ID">
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:DanielConnectionString %>"
SelectCommand="SELECT * FROM [Schools]"></asp:SqlDataSource>
</td>
</tr>
<tr>
<td>Class</td>
<td>
<asp:ScriptManager ID="ScriptManager2" runat="server" />
<asp:DropDownList ID="ClassRegister" runat="server"
DataSourceID="SqlDataSource2" DataTextField="ClassName" DataValueField="ID">
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource2" runat="server"
ConnectionString="<%$ ConnectionStrings:DanielConnectionString %>"
SelectCommand="SELECT * FROM [Class] WHERE ([SchoolID] = @SchoolID)">
<SelectParameters>
<asp:ControlParameter ControlID="SchoolRegister" Name="SchoolID"
PropertyName="SelectedValue" Type="Int32" />
</SelectParameters>
</asp:SqlDataSource>
</td>
</tr>
Appreciate any assistance provided.