Ms'S

private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
{
	// 使用Items.Clear()之前, 先將Value = null
	// 就可避免觸發dataGridView1_DataError		
	dataGridView1.CurrentRow.Cells["ColumnName1"].Value = null; 
	(DataGridViewComboBoxCell)dataGridView1.CurrentRow.Cells["ColumnName1"]).Items.Clear();
}

private void dataGridView1_DataError(object sender, DataGridViewDataErrorEventArgs e)
{
	// e.Exception = DataGridViewComboBoxCell 值無效
	// e.Context = formatting | Display
	if (e.Exception != null && e.Context == DataGridViewDataErrorContexts.Commit)
	{
		MessageBox.Show("Commit error");
	}
}