Question

Does anyone how can I get the parameters for SelectParameters from another dropdown in c# .net?

I check online , and I follow the steps that been told, but it’s doesn’t seem working for me.

Code:

If I have the following code to retrieved the data for a dropdown:

    <asp:DropDownList ID="DropDownVisaType" runat="server" DataSourceID="dsDropDownVisaType" CssClass="dsDropDownVisaType"
    DataValueField="VisaTypeID" DataTextField="VisaType" AppendDataBoundItems="true" >
        <asp:ListItem></asp:ListItem>
        </asp:DropDownList>  
        <asp:SqlDataSource ID="dsDropDownVisaType" runat="server" ConnectionString="<%$ ConnectionStrings:SmartStaffConnectionString %>"
           SelectCommand="app_visa_type_select" SelectCommandType="StoredProcedure">
        </asp:SqlDataSource>

After I select the dropdown, I want to use the VisaTypeID from the dropdown to retrieve data from another dropdown as below:

    <asp:DropDownList ID="DropDownVisaTypeSpecific" runat="server" DataSourceID="dsDropDownVisaTypeSpecific" CssClass="dsDropDownVisaTypeSpecific"
    DataValueField="VisaTypeSpecificID" DataTextField="VisaTypeSpecific" AppendDataBoundItems="true" >
        <asp:ListItem></asp:ListItem>
        </asp:DropDownList>  
        <asp:SqlDataSource ID="dsDropDownVisaTypeSpecific" runat="server" ConnectionString="<%$ ConnectionStrings:SmartStaffConnectionString %>"
           SelectCommand="app_visa_type_specific_select" SelectCommandType="StoredProcedure">
            <SelectParameters>
              <asp:ControlParameter Property="SelectedValue" ControlID="DropDownVisaType" Name="VisaTypeID" Type="Int32" />
            </SelectParameters>
        </asp:SqlDataSource>

Does anyone know what is my code going wrong and how can I make it work?

Answer 1

There is an event SelectedIndexChanged for A dropdown by using that you can get the value of selected Item.
Like below:

  protected void DropDownVisaType_SelectedIndexChanged(object sender, EventArgs e)
{
  Int32 value = Convert.ToInt32(DropDownVisaType.SelectedItem.Value);
  DropDownVisaTypeSpecific.DataSource=Method_Name(Value);
  DropDownVisaTypeSpecific.DataBind();
}