在 CellPainting 中更改 DataGridViewCheckBoxCell 背景色

Question

I am trying to override the default DataGridViewCheckBoxCell with a colored rectangle.

I found the following post but it doesn't behave as expected: Drawing a filled circle or rectangle inside a DataGridViewCell in C# Winforms

Here is my code:

private void OrdersComponentsDGV_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
{
    if (e.RowIndex >= 0 && e.ColumnIndex > 0)
    {
        const float size = 20;

        var datagridview = (sender as DataGridView);
        var cell = datagridview.Rows[e.RowIndex].Cells[e.ColumnIndex];

        if (cell.Value != DBNull.Value && (bool)cell.Value)
        {
            //  center of the cell
            var x = e.CellBounds.X + e.CellBounds.Width / 2 - size/2;  
            var y = e.CellBounds.Y + e.CellBounds.Height / 2 - size/2;

            RectangleF rectangle = new RectangleF(x, y, size, size);
            e.Graphics.FillRectangle(Brushes.Yellow, rectangle);                    
            e.PaintContent(e.CellBounds);                    
            e.Handled = true;
        }
    }
}

After loading for the first time, all checked cells have a Gray backcolor. It disappear after scrolling the datagridview down and up back.

Illustration:

In addition, I set the DataGridView SelectionMode to FullRowSelect:

OrdersComponentsDGV.SelectionMode = DataGridViewSelectionMode.FullRowSelect;

But after I implement CellPainting as described above, the blue selection backcolor is gone (see in the image) where the checkbox is checked.

Answer 1

you can use base background painting method before drawing your own rectangle (just like documentation for DataGridView.CellPainting Event suggests)

if (cell.Value is bool && (bool)cell.Value)
{
    e.PaintBackground(e.ClipBounds, cell.Selected);    

    //  center of the cell
    var x = e.CellBounds.X + e.CellBounds.Width / 2 - size / 2;  
    var y = e.CellBounds.Y + e.CellBounds.Height / 2 - size / 2;

    RectangleF rectangle = new RectangleF(x, y, size, size);
    e.Graphics.FillRectangle(Brushes.Yellow, rectangle);

    e.PaintContent(e.ClipBounds);

    e.Handled = true;
}