Hi Dib,
Thank you for using Syncfusion products.
We would like to let you know that you can use the CoveredRanges
option and can merge the required range of cells and then you can apply the border to
it. Please refer the below code snippet.
C#:
this.gridControl1.CoveredRanges.Add(GridRangeInfo.Cells(2,2,4,8));
this.gridControl1[2,
2].Borders.All = new GridBorder(GridBorderStyle.Solid, Color.Red,
GridBorderWeight.Thin);
Please let us know if you need any further assistance.
Regards,
Anish