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Add an extra header to an ASP.NET DataGrid

, 9 Dec 2005 CPOL
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This article explains how to add an extra header item to a standard ASP.NET DataGrid.

Sample Image - grid.jpg

Introduction

This article explains how to add an extra header item to a standard ASP.NET DataGrid.

Using the code

The code is pretty simple. The grid is built using a DataGridTable object. All we have to do is to add a DataGridItem to the Rows collection in the CreateControlHierarchy method of our custom grid. Now I'll let the code talk:

Protected Overrides Sub CreateControlHierarchy(ByVal useDataSource As Boolean)
    MyBase.CreateControlHierarchy(useDataSource)
    If Not ShowExtraHeader Then Return
    If Controls.Count > 0 Then
        'get all grid's items (rows)
        Dim rows As TableRowCollection = DirectCast(Controls(0), Object).Rows
        'create extra header item
        Dim extraHeaderRow As DataGridItem = CreateItem(-1, -1, ListItemType.Header)
        'set an id that will identify it in ItemCreated event
        extraHeaderRow.ID = "extraheader"
        'create an event attached to our item
        Dim extraHeaderRowArgs As New DataGridItemEventArgs(extraHeaderRow)
        'call ItemCreated event
        OnItemCreated(extraHeaderRowArgs)
        'finally add the extra header item to the items's collection
        rows.AddAt(0, extraHeaderRow)
    End If
End Sub

And let's see how we could use this code in a real scenario:

Private Sub g_ItemCreated(ByVal sender As Object, ByVal e _
            As System.Web.UI.WebControls.DataGridItemEventArgs) Handles g.ItemCreated
    If e.Item.ItemType = ListItemType.Header Then
        If e.Item.ID = "extraheader" Then
            Dim refreshCell As New TableCell
            refreshCell.ColumnSpan = 2
            refreshCell.HorizontalAlign = HorizontalAlign.Center
            Dim btnRefresh As New Button
            btnRefresh.Text = "Refresh"
            refreshCell.Controls.Add(btnRefresh)
            AddHandler btnRefresh.Click, AddressOf btnRefresh_Click

            Dim parentsCell As New TableCell
            parentsCell.ColumnSpan = 2
            parentsCell.HorizontalAlign = HorizontalAlign.Center
            parentsCell.Text = "Parents"

            e.Item.Cells.Add(refreshCell)
            e.Item.Cells.Add(parentsCell)
        End If
    End If
End Sub

That's all! Check the demo project to see all the bits.

History

  • Dec. 10, 2005 - Version 1.0.

License

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

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About the Author

Gabriel Sirbu
Web Developer
United States United States
No Biography provided

Comments and Discussions

 
Questionhow do i remove paging [modified] Pinmembermaya_zakry3-Jun-07 23:47 
GeneralItem_Databoud Event Pinmemberjhkss2-Nov-06 10:49 
GeneralA Better Alternative. PinmemberMiguel_TX29-Apr-06 19:40 
Check out this solution:
http://forums.asp.net/390809/ShowPost.aspx[^]
 
Here is the C# Equivalent (with some added stuff I did to help those with possible questions):
private void DataGrid1_PreRender(object sender, System.EventArgs e)
{
//This MUST be done in the Pre-Render function. Otherwise will have errors if running this code outside of the PreRender function.
DataGridItem dgItem = new DataGridItem(0,0,ListItemType.Header);
TableCell myCell = new TableCell();
myCell.ColumnSpan = 2; //This Merges Cells together.
myCell.Text = "Test";
myCell.BackColor = Color.Lavender; //Change the back color of a single cell.
myCell.VerticalAlign = VerticalAlign.Middle;//This Centers the text vertically for a single cell.
dgItem.Cells.Add(myCell);
dgItem.HorizontalAlign = HorizontalAlign.Center;//This centers the text for the entire dgItem (which in this case is the additional header we just added).
DataGrid1.Columns[1].HeaderStyle.BackColor = Color.LemonChiffon;//This changes the color for an entire column, not needed, but is neat to see if you were thinking about doing something like this in the future - now you know how to.
DataGrid1.Controls[0].Controls.AddAt(0, dgItem); //Change the integer in the AddAt() function to insert the header somewhere else in the datagrid (like 1 for below the original header, or 5 if for some inexplicable reason you want two totally separated headers with rows of data in between them.
}
 
Hope you guys liked it! Big Thanks to Jim Ross and his post at forums.ASP.Net website and his source who gave him the original VB code: Anand Hegde (MSFT).
- M

GeneralRe: A Better Alternative. PinmemberGabriel Sirbu30-Apr-06 21:33 
GeneralRe: A Better Alternative. PinmemberJoel Pearson22-May-06 23:04 
GeneralRe: A Better Alternative. PinmemberMiguel_TX12-Jun-06 21:32 
GeneralRe: A Better Alternative. Pinmemberdga20522-Jun-06 5:41 
Generalc# PinmemberMark Lawson29-Dec-05 10:39 
GeneralRe: c# Pinmembersyao16825-Feb-06 11:07 
Generalc# PinmemberMark Lawson29-Dec-05 10:38 

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