How to Merge Cells with Equal Values in a GridView

Mykola Tarasyuk

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20 Mar 2009CPOL

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My solution is not the first; however, I think, it is rather universal and very short - less than 20 lines of the code...

In this tip, you will learn a universal and short method to merge GridView rows if neighboring cells show equal values.

Download sample code - 3.3 KB

Introduction

There are a lot of methods on the Internet solving the problem of how to merge GridView rows if neighboring cells show equal values. My approach is not the first; however, I think, it is rather universal and very short - less than 20 lines of code.

The algorithm is simple: to bypass all the rows, starting from the second at the bottom, to the top. If a cell value is the same as a value in the previous (lower) row, then increase RowSpan and make the lower cell invisible, and so forth.

The code that merges the cells is very short:

public class GridDecorator
{
    public static void MergeRows(GridView gridView)
    {
        for (int rowIndex = gridView.Rows.Count - 2; rowIndex >= 0; rowIndex--)
        {
            GridViewRow row = gridView.Rows[rowIndex];
            GridViewRow previousRow = gridView.Rows[rowIndex + 1];

            for (int i = 0; i < row.Cells.Count; i++)
            {
                if (row.Cells[i].Text == previousRow.Cells[i].Text)
                {
                    row.Cells[i].RowSpan = previousRow.Cells[i].RowSpan < 2 ? 2 : 
                                           previousRow.Cells[i].RowSpan + 1;
                    previousRow.Cells[i].Visible = false;
                }
            }
        }
    }
}

The last action is to add an OnPreRender event handler for the GridView:

protected void gridView_PreRender(object sender, EventArgs e)
{
    GridDecorator.MergeRows(gridView);
}

History

20^th March, 2009: Initial version

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By

Mykola Tarasyuk

Software Developer (Senior)

Ukraine

I'm a software developer from Ukraine. I write about ASP.NET and other .NET related topics over at my blog

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How to Merge Cells with Equal Values in a GridView

Introduction

History

License

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