Solved! Smth like this: <asp:DropDownList ID="Fclty_ddl" runat="server" AutoPostBack="True" OnSelectedIndexChanged="Fclty_ddl_SelectedIndexChanged"> </asp:DropDownList> <asp:DropDownList ID="Group_ddl" runat="server" AutoPostBack="True" OnSelectedIndexChanged="Group_ddl_SelectedIndexChanged"> </asp:DropDownList>
protected void Page_Load(object sender, EventArgs e)
{
web = SPContext.Current.Web;
fctLS = web.Lists["List1"]; // faculty list
groupLS = web.Lists["List2"]; // group list with lookup from faculty list
if (!IsPostBack)
{
SPListItemCollection items1 = fctLS.Items;
DataTable dt1 = items1.GetDataTable();
Fclty\_ddl.DataSource = dt1;
Fclty\_ddl.DataValueField = "ID";
Fclty\_ddl.DataTextField = "Fclty";
Fclty\_ddl.DataBind();
SPListItemCollection items2 = groupLS.Items;
DataTable dt2 = items2.GetDataTable();
Group\_ddl.DataSource = dt2;
Group\_ddl.DataValueField = "ID";
Group\_ddl.DataTextField = "Group";
Group\_ddl.Enabled = false;
Group\_ddl.DataBind();
}
}
protected void Fclty\_ddl\_SelectedIndexChanged(object sender, EventArgs e)
{
SPQuery queryq = new SPQuery();
queryq.Query = string.Format("<Where>" +
"<Eq>" +
"<FieldRef Name='Fclty' LookupId='True'/>" +
"<Value Type='Lookup'>{0}</Value>" +
"</Eq>" +
"</Where>", Fclty\_ddl.SelectedValue);
SPListItemCollection items = groupLS.GetItems(queryq);
DataTable dt = items.GetDataTable();
Group\_ddl.DataSource = dt;
Group\_ddl.DataTextField = "Group";
Group\_ddl.DataValueField = "ID";
Group\_ddl.DataBind();
}
