private void comboBoxExamples_SelectedIndexChanged(object sender, EventArgs e) { _query.Clear(); // HOWTO: Create a query programmatically switch (comboBoxExamples.SelectedIndex) { case 0: LoadQuerySimple(); break; case 1: LoadQueryWithLeftJoin(); break; case 2: LoadQueryWithAggregateAndGroup(); break; case 3: LoadQueryWithDerivedTableAndCte(); break; case 4: LoadQueryWithUnions(); break; case 5: LoadQueryWithSubQueryExpression(); break; default: throw new ArgumentOutOfRangeException(); } }