C#

enum YesNo
{
	Y,
	N
}
private void Form1_Load(object sender, System.EventArgs e)
{
	DataTable tbl = new DataTable("testTable");

	// The "bit" column would come from the database, the "Y/N" column
	// is added in code.
	tbl.Columns.Add( "bit", typeof(bool) );
	tbl.Columns.Add( "Y/N", typeof(YesNo) );

	// Add a YesNo value for the boolean value in each row.
	tbl.Rows.Add( new object[] { true,  YesNo.Y } );
	tbl.Rows.Add( new object[] { false, YesNo.N } );

	this.dataGrid1.DataSource = tbl;

	tbl.RowChanged += new DataRowChangeEventHandler(tbl_RowChanged);

	DataGridTableStyle style = new DataGridTableStyle();
	style.MappingName = "testTable";
	this.dataGrid1.TableStyles.Add( style );
	style.GridColumnStyles.Remove( style.GridColumnStyles["bit"] );
}

private void tbl_RowChanged(object sender, DataRowChangeEventArgs e)
{
	if( e.Action == DataRowAction.Change )
		e.Row["bit"] = ((YesNo)e.Row["Y/N"]) == YesNo.Y;
}

joaoafonso wrote:

//code to treat user's choice

try
{
	MessageBox.Show(this.listBox.Items[0].ToString());
}
catch (Exception e)
{
	MessageBox.Show(e.ToString());
}

if (this.listBox.Items[0] == null)
{
	MessageBox.Show(@"No item at index 0");
}
else
{
	MessageBox.Show(this.listBox.Items[0].ToString());
}