Most of this code comes from or follows the walkthrough (Using a
DataGrid Web Control to Read and Write Data). The problem is that as
soon as you click the Edit link, the data rows disappear, leaving you
with just the header row. I've figured out what's happening, but can't
figure out why.
Following along with the debugger, as soon as you click Edit, execution
goes to Page_Load, and at that point, before it even checks postback,
the dataset is empty. All the rows are gone. Anyone know why?
I suppose I could refill the dataset in Page_Load, but that leads to the
dreaded "Old Values" problem.
This doesn't make sense! Why would the bottom fall out of the dataset?
The structure is still there, all the column names and everything, but
the data itself is gone -- rows.count returns 0.
Thanks for any help!
Private Sub Page_Load(ByVal sender As System.Object, ByVal e ...
If Not Page.IsPostBack Then
OleDbDataAdapter1.Fill(myDataSet1)
DataGrid1.DataBind()
End If
End Sub
Private Sub DataGrid1_EditCommand(ByVal source As Object, ByVal e ...
DataGrid1.EditItemIndex = e.Item.ItemIndex
DataGrid1.DataBind()
End Sub
Private Sub DataGrid1_CancelCommand(ByVal source As Object, ByVal e...
DataGrid1.EditItemIndex = -1
DataGrid1.DataBind()
End Sub
Private Sub DataGrid1_UpdateCommand(ByVal source As Object, ByVal e...
Dim key As String = DataGrid1.DataKeys(e.Item.ItemIndex).ToString()
Dim strA, strB, strC As String
Dim txt As TextBox
txt = CType(e.Item.Cells(1).Controls(0), TextBox)
strA = txt.Text
txt = CType(e.Item.Cells(2).Controls(0), TextBox)
strB = txt.Text
txt = CType(e.Item.Cells(3).Controls(0), TextBox)
strC = txt.Text
Dim r As myDataSet.XRow
r = myDataSet1.X.FindByRecID(key)
r.A = strA
r.B = strB
r.C = strC
OleDbDataAdapter1.Update(myDataSet1)
DataGrid1.EditItemIndex = -1
DataGrid1.DataBind()
End Sub
End Class 4 1462
Typically you only fill the DataSet once - the first Page_Load event.
After that the DataGrid will keep around the data it needs to
redisplay in the ViewState. Are you checking for rows in the DataSet
or data in the DataGrid on postback?
--
Scott http://www.OdeToCode.com I suppose I could refill the dataset in Page_Load, but that leads to the dreaded "Old Values" problem.
This doesn't make sense! Why would the bottom fall out of the dataset? The structure is still there, all the column names and everything, but the data itself is gone -- rows.count returns 0.
Thanks for any help!
Private Sub Page_Load(ByVal sender As System.Object, ByVal e ... If Not Page.IsPostBack Then OleDbDataAdapter1.Fill(myDataSet1) DataGrid1.DataBind() End If End Sub
Private Sub DataGrid1_EditCommand(ByVal source As Object, ByVal e ... DataGrid1.EditItemIndex = e.Item.ItemIndex DataGrid1.DataBind() End Sub
Private Sub DataGrid1_CancelCommand(ByVal source As Object, ByVal e... DataGrid1.EditItemIndex = -1 DataGrid1.DataBind() End Sub
Private Sub DataGrid1_UpdateCommand(ByVal source As Object, ByVal e... Dim key As String = DataGrid1.DataKeys(e.Item.ItemIndex).ToString() Dim strA, strB, strC As String Dim txt As TextBox txt = CType(e.Item.Cells(1).Controls(0), TextBox) strA = txt.Text txt = CType(e.Item.Cells(2).Controls(0), TextBox) strB = txt.Text txt = CType(e.Item.Cells(3).Controls(0), TextBox) strC = txt.Text
Dim r As myDataSet.XRow r = myDataSet1.X.FindByRecID(key) r.A = strA r.B = strB r.C = strC OleDbDataAdapter1.Update(myDataSet1) DataGrid1.EditItemIndex = -1 DataGrid1.DataBind() End Sub End Class
Scott Allen <bitmask@[nospam].fred.net> wrote: Typically you only fill the DataSet once - the first Page_Load event. After that the DataGrid will keep around the data it needs to redisplay in the ViewState.
Do you know if it does this automatically? Or is there some coding to do
to accomplish this?
Are you checking for rows in the DataSet or data in the DataGrid on postback?
Well, the data is gone from both places. It's the same data, isn't it?
Or does the DataGrid actually make a copy?
On Fri, 02 Jan 2004 09:46:16 -0800, "tr****@sirius.com.no.more"
<us**@example.com> wrote: Scott Allen <bitmask@[nospam].fred.net> wrote:
Typically you only fill the DataSet once - the first Page_Load event. After that the DataGrid will keep around the data it needs to redisplay in the ViewState.
Do you know if it does this automatically? Or is there some coding to do to accomplish this?
This happens automatically unless you have EnableViewState = false
somwhere in the code or in the ASPX. Are you checking for rows in the DataSet or data in the DataGrid on postback?
Well, the data is gone from both places. It's the same data, isn't it? Or does the DataGrid actually make a copy?
The DataSet object will be empty for certain in Page_Load, but the
DataGrid should be reloaded with values kept in the ViewState on the
client.
You might want to look through the following article and compare code
to see what is different:
Walkthrough: Using a DataGrid Web Control to Read and Write Data http://msdn.microsoft.com/library/de...dwritedata.asp
Hope this helps,
--
Scott
--
Scott http://www.OdeToCode.com
Scott Allen <bitmask@[nospam].fred.net> wrote: On Fri, 02 Jan 2004 09:46:16 -0800, "tr****@sirius.com.no.more" <us**@example.com> wrote:
Scott Allen <bitmask@[nospam].fred.net> wrote:
Typically you only fill the DataSet once - the first Page_Load event. After that the DataGrid will keep around the data it needs to redisplay in the ViewState. Do you know if it does this automatically? Or is there some coding to do to accomplish this?
This happens automatically unless you have EnableViewState = false
Oh, right. That's something to check.
You might want to look through the following article and compare code to see what is different:
Walkthrough: Using a DataGrid Web Control to Read and Write Data http://msdn.microsoft.com/library/de...dwritedata.asp
Okay, thanks. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
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