Vista - SetColumnError Takes a Long Time to Execute

I have a data table with ~1000 rows. I go through the rows one at a time,
checking the contents. If I find a cell with an error, e.g containing null,
I use SetColumnError on the data row to flag it.

Here's my code:

For Each dr As DataRow In MyDataTable.Rows
Dim MyValue As Integer

If dr("ID").Equals(DBNull.Value) Then
dr.SetColumnError("ID", "ID cannot be null") ' this take 1 to 2
seconds each time
Else
MyValue = CType(dr("ID"), Integer)
End If

...
Next

The problem is each call to SetColumnError takes about 1-2 seconds to
execute. This is an ice-age, and if I have 100 cells to flag it takes 100
seconds to go through the data.

Does anyone know why it takes so long for this method to execute?

I am using VS2008 SP1 on XP SP3. I am targeting V3.5 of the framework,
although I have V3.5 SP1 installed. This was a problem before I installed
SP1 though. The back-end is SQL Server 2005, but the data are disconnected,
so I can't see that being an issue.

TIA

Charles

Hi Charles,

Takes in Brittain a second the same time as at the continent?

:-)

\\\
Module Module1

Sub Main()
Dim a As New Stopwatch
a.Start()
Dim myDataTable As New DataTable
Dim ID As New DataColumn("ID")
myDataTable.Columns.Add(ID)

For i As Integer = 0 To 100
Dim dr = myDataTable.NewRow
dr("ID") = DBNull.Value
myDataTable.Rows.Add(dr)
Next

For Each dr As DataRow In myDataTable.Rows
Dim MyValue As Integer

If dr("ID").Equals(DBNull.Value) Then
dr.SetColumnError("ID", "ID cannot be null") ' this take
1 to 2 seconds each time
Else
MyValue = CType(dr("ID"), Integer)
End If
Next
Console.WriteLine(a.ElapsedMilliseconds / 1000)
Console.ReadLine()
End Sub

End Module
///

Cor

"Charles Law" <blank@xxxxxx> schreef in bericht
news:%23E3yLXQFJHA.6052@xxxxxx

Hi Cor

Good to hear from you. I tried your test, and it takes only a fraction of a
second, so there is obviously something about my data table that is causing
the problem.

I've just had another thought: I am using the data table as the data source
for a grid. I wonder if the fact that the grid is bound to the data table is
what is making it so slow. I'll have to look into that.

Cheers

Charles


"Cor Ligthert[MVP]" <notmyfirstname@xxxxxx> wrote in message
news:1F477A33-E6A9-4172-8DEA-29990C637A72@xxxxxx

Charles Law wrote:Maybe .SuspendLayout and .ResumeLayout on the grid would help?

Andrew

Hi Andrew

I did try that and it didn't improve things. It seems that it is the fact
that the data table is the data source for the grid. I set the data source
to Nothing and the SetColumnError takes a fraction of a second. So, I create
a copy of my data table to work on and then use the copy as the data source
at the end. I couldn't really think of a better way.

Cheers

Charles


"Andrew Morton" <akm@xxxxxx-press.co.uk.invalid> wrote in message
news:6jrpplF4pe4sU1@xxxxxx

Hi Steve

I tried the Nothing thing before, which did work, but decided to make a copy
instead to avoid the grid going blank during the process, but I appreciate
it will take longer when the data table has many rows.

I will try the BeginDataLoad though; that sounds like it could work.

Cheers

Charles


"Steve Gerrard" <mynamehere@xxxxxx> wrote in message
news:ZpmdnVQFfMjx7UPVnZ2dnUVZ_gudnZ2d@xxxxxx