Merge GridView Cells Or Columns in Row ASP.NET

In most of the cases specially for reporting purpose we need to merge GridView cells or columns for client preferred output. In this example i will show you how one can merge GridView cells or columns in asp.net C#. My special focus is on to merge cells when both contains same or equal data. So that the GridView looks like a traditional report. For merging GridView cells here i want to show you a generic way so that you can use only one common method for all GridViews in your project where applicable. Let i have 3 tables named Brand,Category and product. I want to merge all brand & category if consecutive rows contains same data. Look at my below sample data: