Merging DataGrid Header Columns

Introduction

This article describes a simple trick to merge the header columns of a DataGrid at run-time.

Background

I found a similar solution: Merge DataGrid Header, but I wanted to do this in 2-3 lines of code. So, I tried to use the members of the DataGrid to achieve the results.

Using the code

In the ItemCreated event of the DataGrid, catch the header item of the DataGrid. Suppose you want to merge n columns (cells of the header row), then remove n-1 cells from the header item. Then, make the column span property of the remaining cell equal to n. Then, add a table to the cell according to your requirements. The code below demonstrates the merging of two columns, which will result as shown in the above diagram.

C#

private void  Sub Datagrid1_ItemCreated(object sender, 
        System.Web.UI.WebControls.DataGridItemEventArgs e )
{
    //If Header item
    
    If (e.Item.ItemType = = ListItemType.Header)
    {
        e.Item.Cells.RemoveAt(2);
        e.Item.Cells(1).ColumnSpan = 2;
        //Insert the table shown in the diagram 3
        // to the Text property of the Cell
        e.Item.Cells(1).Text = "<table style='FONT-WEIGHT: bold; WIDTH:" + 
              " 100%; COLOR: white; TEXT-ALIGN: center'><tr align" + 
              " =center><td colspan = 2 style='BORDER-BOTTOM:" + 
              " cccccc 1pt solid'>Name</td></tr>" + 
              "<tr align =center ><td style ='BORDER-RIGHT:" + 
              " cccccc 1pt solid'>F Name</td><td>L" + 
              " Name</td></tr></table>";
    }  
}

VB.NET

Private Sub Datagrid1_ItemCreated(ByVal sender As _
         Object, ByVal e System.Web.UI.WebControls.DataGridItemEventArgs)_
         Handles Datagrid1_ItemCreated 
    'If Header item
    
    If e.Item.ItemType = ListItemType.Header Then
       e.Item.Cells.RemoveAt(2)
       e.Item.Cells(1).ColumnSpan = 2
       'Insert the table shown in the diagram 3 to the Text property of the Cell
       e.Item.Cells(1).Text = "<table style='FONT-WEIGHT: bold;" & _ 
         " WIDTH: 100%; COLOR: white; TEXT-ALIGN: center'><tr" & _ 
         " align =center><td colspan = 2 style='BORDER-BOTTOM:" & _ 
         " cccccc 1pt solid'>Name</td></tr>" & _
         "<tr align =center ><td style ='BORDER-RIGHT:" & _ 
         " cccccc 1pt solid'>F Name</td><td>L" & _ 
         " Name</td></tr></table>"
    End If  
End Sub