Webforms Datagrid Sorting/Paging...

[Guest]

Hi,

I am trying to figure out why my datagrid has stopped firing the page and
sort commands.

Scenario:

I originally had template columns in my datagrid and had set up custom
bi-directional sorting as well as paging of the datagrid records.

It worked fine. Then I decided to be clever on an update and thought I'd
create the template columns programmatically - which I have done.

Problem is, the paging command and sort commands have stopped firing.

Please could someone give me advice on how to solve the problem.

Here is my set up:

Datagrid properties:

OnSortCommand="DataGrid1_Sort"
OnPageIndexChanged="DataGrid1_Page"

Sort Command:

Sub DataGrid1_Sort(ByVal sender As Object, ByVal e As
DataGridSortCommandEventArgs) Handles DataGrid1.SortCommand
' Check to see if the column we clicked on is the current column
defined
' in the sortCriteria property.
If Me.sortCriteria = e.SortExpression Then
If Me.sortDir = "desc" Then
Me.sortDir = "asc"
Else
Me.sortDir = "desc"
End If
End If
' Assign the column clicked to the sortCriteria property
Me.sortCriteria = e.SortExpression
' Now call the procedure to re-display the Data Grid
DisplayGrid()
End Sub


Page COmmand:

Sub DataGrid1_Page(ByVal sender As Object, ByVal e As
DataGridPageChangedEventArgs) Handles DataGrid1.PageIndexChanged
DataGrid1.CurrentPageIndex = e.NewPageIndex
DisplayGrid()
End Sub

Example of template column:

Dim tDate As BoundColumn = New BoundColumn
With tDate
.HeaderText = "Date of B'Cast"
.DataField = "Coverage_Date"
.SortExpression = "Coverage_Date"
.DataFormatString = "{0:d}"
.HeaderStyle.Width = Unit.Point(60)
.HeaderStyle.VerticalAlign = VerticalAlign.Top
End With
DataGrid1.Columns.AddAt(ColIndex, tDate)

thanks,

KS

 

[Brock Allen]

Two things might be the cause:

1) The designer has somehow removed the event handles for the sorting and
pagaing. This is a well known problem (at least in C#) and it happens sometimes.

2) You're not recreating the DataGrid upon postback. Anything you do dynamically
needs to be recreated upon every postback. I'd suggest doing this in CreateChildControls
of the Page. The hard part is "remembering" across postbacks what you had
added dynamically. Storing your own custom data in viewstate to remember
this is a good approach.

 

[Guest]

Hi Allen, thx for your reply.

The event handles are actually there in the code I posted.

Also, the DisplayGrid() method does re-create the template columns.

The problem is that at the moment is that the sort and paging events are not
firing.

regards,

KS