Application Hang during OleDbDataAdapter.Fill

**=?Utf-8?B?TG9yZCBHb29zRmFuY2l0bw==?=** · Jun 27 '08, 08:15 PM

Re: Application Hang during OleDbDataAdapte r.Fill

Hi!.
I have one question. Where be declarate this procedure?

AsyncProcess = New AsynchMethodInv oker(AddressOf Me.DoSomething)

I can see that AsynchMethodInv oker(...) is call... but where be declarate?

Tank.

"Michel Posseth [MCP]" wrote:

"Marcolino" <marco.pozzuolo @gmail.comschre ef in bericht
news:69281328-905c-48d8-94ed-463dbe490b1e@d2 1g2000prf.googl egroups.com...

Hi all,
I'm using this code to export entire table from access to xml file.

DScmdXML = New OleDb.OleDbComm and(sqlXML, conn)
DScmdXML = New OleDb.OleDbData Adapter(cmdXML)
DScmdXML.Fill(D SXML, sTableName)
DSXML.WriteXml( sFileName, XmlWriteMode.Wr iteSchema)
Dim xmlSW2 As System.IO.Strea mWriter = New
System.IO.Strea mWriter(sFullPa th)
DSXML.WriteXml( xmlSW2, XmlWriteMode.Wr iteSchema)
xmlSW2.Flush()
xmlSW2.Close()

During DScmdXML.Fill(D SXML, sTableName) command the application hangs.
In some case I need to export big tables, I would like to add a
progress bar during the process, but the bar does not work and
application seems frezed. I tried to add a
System.Windows. Forms.Applicati on.DoEvents(), but nothing change.

Do you have any suggestion?

Many Thanks

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Hello ,
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If you want a responsive UI, while your program is verry bussy , you might
investigate asynchrounous processing ( multi threading )
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i have once written some examples for this newsgroup how to acomplish this
in an easy way with Async delegates
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here is one :
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take a form throw 2 buttons on it and a progressbar
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call the progressbar pbmain
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now copy paste this :
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Imports System.Threadin g
Public Class Form1
Private Mvar_Cancell As Boolean
Friend Property Cancell() As Boolean
Get
Return Mvar_Cancell
End Get
Set(ByVal value As Boolean)
Mvar_Cancell = value
Me.Button1.Enab led = value
End Set
End Property
Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
System.EventArg s) Handles Button1.Click
Me.Cancell = False
With pbMain
.Value = 0
.Maximum = 100
.Minimum = 0
End With
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Dim AsyncProcess As New AsynchMethodInv oker(AddressOf Me.pbLoop)
AsyncProcess.Be ginInvoke(Nothi ng, Nothing)
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AsyncProcess = New AsynchMethodInv oker(AddressOf Me.DoSomething)
AsyncProcess.Be ginInvoke(Nothi ng, Nothing)
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End Sub
Private Sub Button2_Click(B yVal sender As System.Object, ByVal e As
System.EventArg s) Handles Button2.Click
Cancell = True
End Sub
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Private Sub DoSomething()
Do While Not Me.Cancell
Debug.WriteLine ("hello world")
Loop
End Sub
Delegate Sub CrossThreadInvP araMB(ByVal val As Integer)
Private Sub pbLoop()
Dim i As Integer
Do While Not Me.Cancell
Thread.Sleep(50 )
i += 1
If i = 101 Then i = 0
SetPbValue(i)
Loop
i = 100
SetPbValue(i)
End Sub
Delegate Sub AsynchMethodInv oker()
Public Sub SetPbValue(ByVa l Count As Integer)
If Me.pbMain.Invok eRequired Then
Dim d As New CrossThreadInvP araMB(AddressOf SetPbValue)
Try
Me.Invoke(d, New Object() {Count})
Catch ex As Exception
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End Try
Else
Me.pbMain.Value = Count
End If
End Sub
Private Sub Form1_FormClosi ng(ByVal sender As Object, ByVal e As
System.Windows. Forms.FormClosi ngEventArgs) Handles Me.FormClosing
Me.Cancell = True
End Sub
End Class
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i hope this gives you all an idea in what i mean ,,, the method that is now
updating the progressbar runs in a seperate thread to make it even nicer i
run another worker thread wich prints hello world statements to the debug
window
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these threads can comunicate to the progressbar through the SetPbValue
method
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see for more :
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Error 404 (Niet gevonden)!!1

http://groups.google.nl/groups/search?hl=nl&q=asynchronous+posseth&qt_s=Discussiegroepen+doorzoeken

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Michel
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Application Hang during OleDbDataAdapter.Fill

Application Hang during OleDbDataAdapter.Fill

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