private void addButton_Click(object sender, EventArgs e) { ForeignKey key = new ForeignKey(tableNode.Table, null); if (refTable.SelectedValue != null) { key.SetName(String.Format("FK_{0}_{1}", tableNode.Table.Name, refTable.SelectedValue), true); key.ReferencedTable = refTable.SelectedValue.ToString(); } foreignKeyBindingSource.Add(key); }