Merging Datagrid Header Column

Introduction

Hi all,

     This is my first article in Codeproject. Fortunately I dont have to code the whole process, much of the work has already been done  by irwansyah.

All the credits goes to him, he has done a wonderfull job of going through the pain of how the datgrid rendering works. I just studied his code and modified only a few parts so that it can be programmer friendly . So go to the page http://www.codeproject.com/script/Articles/list_articles.asp?userid=191443 and first of all study the whole code and download the files. I will be using those files only.

This refers only to the second datagrid.What I will do is instead of specyfying each cell manually in the page_load method in the WebForm1.aspx.cs, I will use a function ColMerge() to specify only the columns that are needed to merge.I will use only the ASPNetDatagridDecorator.cs file.

Modifications

First of all I will be modifying the ASPNetDatagridDecorator.cs file. Go to the NewRenderMethod() and delete everything inside it and add the following code.

<pre>

for (int i = 0; i < ctl.Controls.Count; i++)

if (asd.Contains(i))

TableCell item = (TableCell)asd[i];

else

</pre>

The above code loops through all the default datagrid tablecell controls represented by ctl and renders them. The condition is used to check if a custom table cell has been used or not for having merged datagrid headers.

Then add the following code in an independent part of the file(in the class). 

<pre>

Hashtable asd = new Hashtable();

public void ColMerge(string name, int index,int span)

TableCell cell = new TableCell();

cell.HorizontalAlign = HorizontalAlign.Center;