Drawing a filled circle or rectangle inside a DataGridViewCell in C# Winforms

Question

I want to draw a small filled circle in the center of a DataGridViewCell. A rectangle can do the trick as well. I assume I must do it in the CellPainting event.

Answer 1

I finally resolved it. I drew a filled rectangle with the same size as the checkbox and in the same location.

I did the following:

First, I change the DataGridViewCheckBoxCell to DataGridViewTextBoxCell to hide the checkbox.

DataGridViewTextBoxCell blank_cell = new DataGridViewTextBoxCell();
dgv_Cuotas.Rows[row.Index].Cells["Seleccionar"] = blank_cell;
dgv_Cuotas.Rows[row.Index].Cells["Seleccionar"].Style.ForeColor = Color.Transparent;
dgv_Cuotas.Rows[row.Index].Cells["Seleccionar"].Style.SelectionForeColor = Color.Transparent;

Be sure of selecting transparent forecolor so as not to see "False" in the Cell.

After that, I just painted the rectangle in the cell using the cellpainting event:

if (dgv_Cuotas.Columns[e.ColumnIndex].Name == "Seleccionar" && Convert.ToDecimal(dgv_Cuotas.Rows[e.RowIndex].Cells["Restante"].Value) == 0)
            {
                Color c1 = Color.FromArgb(255, 113, 255, 0);
                Color c2 = Color.FromArgb(255, 2, 143, 17);

                LinearGradientBrush br = new LinearGradientBrush(e.CellBounds, c1, c2, 90, true);
                ColorBlend cb = new ColorBlend();
                cb.Positions = new[] { 0, (float)1 };
                cb.Colors = new[] { c1, c2 };
                br.InterpolationColors = cb;

                Rectangle rect = new Rectangle(e.CellBounds.Location.X + 4, e.CellBounds.Location.Y + 4, 13, 13);

                e.Graphics.FillRectangle(br, rect);
                e.PaintContent(rect);
                e.Handled = true;
            }

You can get the location you want by changing the Location.X and Location.Y values like I did.

Hope that helps somebody!