Cascading for multiple selection of checkbox list - asp.net

Question

I want to retrieve data from oracle data base for one Checkbox list to another checkbox List for multiple selection in asp.net.
But unfortunately i am getting same ID again again while debugging.
Please help me Where i am doing mistake.
Is there any another easy approach on same.
I want something like : "Select d.depot_code, d.depot_description from table where d.depot in (depot_code from another Checkbox List) " [with comma separated ID]
CODE:
ddlregion Binding code:
public void BindRegion()
{
OracleCommand Cmd = new OracleCommand("select * from regions", con);
Cmd.CommandType = CommandType.Text;
OracleDataAdapter da = new OracleDataAdapter();
DataSet ds = new DataSet();
da.SelectCommand = Cmd;
da.Fill(ds);
ddlregion.DataSource = ds;
ddlregion.DataTextField = "REGION_DESC";
ddlregion.DataValueField = "REGION_CODE";
ddlregion.DataBind();
}
protected void ddlregion_SelectedIndexChanged(object sender, EventArgs e)
{
ddlDepot.Items.Clear();
ddlDepot.Items.Add(new ListItem("--Select Depot--", ""));
for (int i = 0; i < ddlregion.Items.Count; i++)
{
if (ddlregion.Items[i].Selected == true)
{
string str = "select d.depot_code, d.depot_description from regions r, sub_regions sr, depots d where r.region_code = sr.region_code and sr.sub_region_code = d.sub_region_code and active = 'Y' and d.depot_code = " + ddlregion.SelectedItem.Value + "";
OracleCommand Cmd = new OracleCommand(str, con);
Cmd.CommandType = CommandType.Text;
OracleDataAdapter da = new OracleDataAdapter();
DataSet ds = new DataSet();
da.SelectCommand = Cmd;
da.Fill(ds);
ddlDepot.DataSource = ds;
ddlDepot.DataTextField = "DEPOT_DESCRIPTION";
ddlDepot.DataValueField = "DEPOT_CODE";
ddlDepot.DataBind();
}
}
}
Thanks

Answer 1

Looking at your code again it doesn't look like you need to loop through your region dropdown list. In your ddlRegion_indexchanged just go ahead and bind your ddlDepot drop down and pass it the ddlregion.SelectedValue. So all you need is below, the ddlDepot will bind accordingly when you change the Region because you pass it the selected value every time.
string str = "select d.depot_code, d.depot_description from regions r, sub_regions sr, depots d where r.region_code = sr.region_code and sr.sub_region_code = d.sub_region_code and active = 'Y' and d.depot_code = " + ddlregion.SelectedValue + "";
OracleCommand Cmd = new OracleCommand(str, con);
Cmd.CommandType = CommandType.Text;
OracleDataAdapter da = new OracleDataAdapter();
DataSet ds = new DataSet();
da.SelectCommand = Cmd;
da.Fill(ds);
ddlDepot.DataSource = ds;
ddlDepot.DataTextField = "DEPOT_DESCRIPTION";
ddlDepot.DataValueField = "DEPOT_CODE";
ddlDepot.DataBind();