public class MainActivity : Activity
{
    int count = 1;

    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        // 「メイン」レイアウトリソースからビューを設定する
        SetContentView(Resource.Layout.Main);

        var grid = FindViewById<FlexGrid>(Resource.Id.Grid);

        grid.AutoGenerateColumns = false;
        grid.Columns.Add(new GridColumn() { Binding = "FirstName", Width = GridLength.Star });
        grid.Columns.Add(new GridColumn() { Binding = "LastName", Width = GridLength.Star });
        grid.Columns.Add(new GridBulletGraphColumn() { Binding = "OrderTotal", Header = "注文合計", Width = GridLength.Star });

        var data = Customer.GetCustomerList(100);
        grid.ItemsSource = data;

    }
}

public class GridBulletGraphColumn : GridColumn
{
    protected override object GetCellContentType(GridCellType cellType)
    {
        if (cellType == GridCellType.Cell)
        {
            return typeof(C1BulletGraph);
        }
        else
        {
            return base.GetCellContentType(cellType);
        }
    }

    protected override View CreateCellContent(GridCellType cellType, object cellContentType)
    {
        if (cellType == GridCellType.Cell)
        {
            var gauge = new C1BulletGraph(Grid.Context);
            gauge.Max = 10000;
            gauge.Target = 7000;
            gauge.Bad = 1000;
            gauge.Good = 6000;
            gauge.IsReadOnly = true;
            return gauge;
        }
        else
        {
            return base.CreateCellContent(cellType, cellContentType);
        }
    }

    protected override void BindCellContent(View cellContent, GridCellType cellType, GridRow row)
    {
        if (cellType == GridCellType.Cell)
        {
            var gauge = cellContent as C1BulletGraph;
            gauge.Value = (double)GetCellValue(cellType, row);
        }
        else
        {
            base.BindCellContent(cellContent, cellType, row);
        }
    }
}