e.Percentage not Accurate

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• david connell Redgate › Posts: 172 Silver 1

  July 24, 2006 9:32AM

  Hi there,
  You are not missing anything. Sometimes the % does not get to 100%. It is only a rough % through the task. I am sure that you can understand that some tasks are very difficult to predict, especially as sometimes the sub-elements of the tasks will be run in parallel by using threads.
  Hope this helps
  David

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• jbsound Posts: 35

  July 24, 2006 9:36AM

  Thanks, David.
  
  Confirmed pretty much what I observed.
  
  This leaves me with two choices:
  
  a) Look for another way to determine when the process has finished completely. (Already have another post going on the topic...)
  
  b) Simply set the progress bar I am using to show the percentage complete manually to 100% when the next statement after calling the SQL process in my code is being handled.
  
  I may just have to go with option b).
  
  JB

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• david connell Redgate › Posts: 172 Silver 1

  July 24, 2006 9:50AM

  Hi JB,
  If it was me I would use a similar mechanism to the ProgressDialog code in the Packager C# Templates...
  I would have one Progress Dialog box that ran the task(s) in order on 1 other thread. Then "Invoke" the ProgressInformation back onto the main UI thread.
  This would mean that 'Cancel' would work, plus I would not have to have the Do.Events code, which I assume is necessary to get the UI to update?
  Once the method returns I think that task has finished.
  You will also have to be careful of Exceptions being thrown out of the call to Database.Register and the the exception OperationCancelledException, idicating that the task has been user aborted.
  Regards
  David

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• jbsound Posts: 35

  July 24, 2006 9:57AM

  Thanks, David, for your response. It makes sense reading through your reply. Let me muddle through the code template and see how far I get.
  
  I appreciate your help!
  
  JB

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• jbsound Posts: 35

  July 24, 2006 10:14AM

  David,
  
  Quick question:
  
  Where is the 'ProgressStatusEventHandler' defined?
  
  I looked through the Packager C# Templates and see the reference to the ProgressStatusEventHandler.
  
  Working with VB.NET (and the VB.NET samples supplied) I could not locate the above method.
  
  Thanks,
  
  JB

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• jbsound Posts: 35

  July 24, 2006 10:45AM

  Well, after a bit more digging I assume that ProgressStatusEventHandler is the same as the StatusEventHandler method. Please correct if wrong.
  
  Moving on, I implemented the same methodology, I think, from the C# template and am getting only a little bit further.
  
  Here is what I did:
  

  Sub UpdateProgress(ByVal sender As Object, ByVal e As StatusEventArgs)
          Debug.Writeline(e.Message + ' ' + e.Percentage)
          Me.Invoke(New StatusEventHandler(AddressOf Me.StatusCallbackDataCompare), New Object() {sender, e})
      End Sub
  
      Sub StatusCallbackDataCompare(ByVal sender As Object, ByVal e As StatusEventArgs)
          Debug.WriteLine(e.Percentage.ToString)
          If Not (e.Message Is Nothing) Then
              Me.lstProcess.Items.Add(e.Message.ToString)
          End If
          Application.DoEvents()
          If e.Percentage <> -1 Then
              Me.ultProgressBar.Value = e.Percentage
          End If
          ' Cancel the operation if the user cancels
          If Me.m_CancelSession Then m_Session.CancelOperation()
      End Sub
  
      Private Sub CompareData()
          Session.Status = New StatusEventHandler(AddressOf Me.UpdateProgress) 
          Session.CompareDatabases(db1, db2, mappings)
          Me.ultProgressBar.Value = 100
      End Sub
  

  
  Problem is that it still takes an awefull long time for the progress bar to update, meaning that the compare process is well under way before I get any indication of it in my main UI.
  
  Putting a debug.writeline statement into the UpdateProgress method to see what my percentage and messages look like, I can see that two different threads are working, the one that does the status update reporting and the Invoke thread, which doesn't really start firing until the debug.writeline shows about 35% complete.
  
  I'm afraid I may need some additional pointers to work through this issue. Ideally, I need to have the visual update happen pretty much at the same time that actual percentage complete is reported.
  
  With running two different threads it seems to me that one thread is executed way into the process of the first.
  
  JB

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• david connell Redgate › Posts: 172 Silver 1

  July 24, 2006 10:47AM

  Hi JB
  The code is defined in ProgressDialog after the dialog box
  

  internal interface IProgressExecutor
  {
  		event ProgressStatusEventHandler Status;
  		void CancelExecution();
  		void Execute();
  	}
  
  }
  internal delegate void ProgressStatusEventHandler(object sender, ProgressStatusEventArgs e);
  internal class ProgressStatusEventArgs : EventArgs
  {
  	private string m_Message = null;
  	private int m_Percentage = -1;
  
  	public ProgressStatusEventArgs(string message)
  	{
  		m_Message = message;
  	}
  ....
  }
  
  internal class ProgressCancelException : ApplicationException
  {
  	public ProgressCancelException() {}
  	public ProgressCancelException(string message) : base(message) {}
  	public ProgressCancelException(string message, Exception innerException) : base(message, innerException) {}
  }
  

  So
  ProgressCancelException is roughly equivilant to OperationCancelledException
  ProgressStatusEventArgs is rouglhy equivilant to StatusEventArgs
  IProgressExecutor is roughly equivilant to ICancellable
  Hope that helps.
  David

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• david connell Redgate › Posts: 172 Silver 1

  July 24, 2006 11:03AM

  Hi JB,
  I think that you need to run the Session.Compare on another thread, not the UI one....
  
  To check out some asynch stuff look at: http://www.simple-talk.com/dotnet/windo ... damentals/
  basically I think that your code should be something like....
  
  

  Private void MyDialog_Load(object sender, EventArgs e)
  {
      CompareData() //Kick off compare when form is loaded....
  }
  
  Private Sub CompareData() 
       Session.Status = New StatusEventHandler(AddressOf Me.UpdateProgress) 
  
       m_WorkerThread = new Thread(new ThreadStart(CompareDatabases));
       m_WorkerThread.Start();	
       
      End Sub
  
  private void CompareDatabases()
  {
  //Disable OK button now as the task has not started 
  //Enable  Cancel button as task has not started.. 
  
     Session.CompareDatabases(db1, db2, mappings) ;
  Me.Invoke(New StatusEventHandler(AddressOf Me.StatusCallbackDataCompare), New Object() {sender, new StatusEventArgs(100, ""}) 
  //Enable OK button now as the task has completed
  //Disable Cancel button as task has now finished
  }
  

  Please note I have mixed C# with .NET and this will not compile but you get the drift I hope?
  Regards
  David

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• jbsound Posts: 35

  July 24, 2006 11:11AM

  Definitely helps! Thanks for going the extra mile!
  
  This should do nicely.
  
  JB

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