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Add an extra header to an ASP.NET DataGrid






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