ColumnView.ShownEditor Event

from:

http://documentation.devexpress.com/#WindowsForms/DevExpressXtraGridViewsBaseColumnView_ShownEditortopic

using DevExpress.XtraEditors;
using DevExpress.XtraGrid.Views.Grid;

private DataView clone = null;

private void gridView1_ShownEditor(object sender, System.EventArgs e) {
    GridView view = sender as GridView;
    if (view.FocusedColumn.FieldName == "CityCode" && view.ActiveEditor is LookUpEdit) {
        Text = view.ActiveEditor.Parent.Name;
        DevExpress.XtraEditors.LookUpEdit edit;
        edit = (LookUpEdit)view.ActiveEditor;

        DataTable table = edit.Properties.LookUpData.DataSource as DataTable;
        clone = new DataView(table);
        DataRow row = view.GetDataRow(view.FocusedRowHandle);
        clone.RowFilter = "[CountryCode] = " + row["CountryCode"].ToString();
        edit.Properties.LookUpData.DataSource = clone;
    }
}

private void gridView1_HiddenEditor(object sender, System.EventArgs e) {
    if (clone != null) {
        clone.Dispose();
        clone = null;
    }
}