Using RowPrePaint event of a DataGridView control

To draw a row in a DataGridView control in a different style depending on a certain condition, you can use the RowPrePaint event to interrupt the painting of the rows in the grid.

You then have a choice of which parts of the row to be painted automatically and which parts to paint yourself via the PaintParts event property.

In the code below, I paint a row with a custom brush, depending on the value of a column that is named 'Error'.

   1:  /// <summary>

   2:  /// Handles the drawing of each DataGridView row depending on set log error state.

   3:  /// </summary>

   4:  /// <param name="sender"></param>

   5:  /// <param name="e"></param>

   6:  private void setLogDataGridView_RowPrePaint(object sender, DataGridViewRowPrePaintEventArgs e)

   7:  {

   8:      // Paint all parts of row except SelectionBackground and the Focus box.

   9:      e.PaintParts = DataGridViewPaintParts.All & ~(DataGridViewPaintParts.SelectionBackground | DataGridViewPaintParts.Focus);

  10:   

  11:      // Get the value of the error column of the current row

  12:      string val = this.setLogDataGridView.Rows[e.RowIndex].Cells["Error"].Value.ToString();

  13:   

  14:      if (val != "0")

  15:      {

  16:           // Get rectangle of area to paint with custom brush.

  17:            Rectangle rowBounds = new Rectangle(

  18:             this.setLogDataGridView.RowHeadersWidth, e.RowBounds.Top,

  19:             this.setLogDataGridView.Columns.GetColumnsWidth(

  20:             DataGridViewElementStates.Visible) -

  21:             this.setLogDataGridView.HorizontalScrollingOffset + 1,

  22:             e.RowBounds.Height);

  23:   

  24:      // Disable normal painting of backgrounds.

  25:      e.PaintParts &= ~(DataGridViewPaintParts.Background | DataGridViewPaintParts.ContentBackground);

  26:   

  27:      e.PaintHeader(false);

  28:   

  29:      // Paint the custom background.

  30:      using (Brush lgb = new LinearGradientBrush(rowBounds, Color.Red,

  31:             Color.DarkRed, LinearGradientMode.Vertical))

  32:      {

  33:          e.Graphics.FillRectangle(lgb, rowBounds);

  34:      }

  35:   

  36:      // Set the text colour.

  37:      this.setLogDataGridView.Rows[e.RowIndex].DefaultCellStyle.ForeColor = Color.Yellow;

  38:      this.setLogDataGridView.Rows[e.RowIndex].DefaultCellStyle.SelectionForeColor =      Color.Yellow;

  39:      }

  40:  }