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please help me thread my app.

I have an app that would VASTLY benefit from 30+ threads.   It is on one form.  I have a start and stop button that set "stopper" var.   While stopper is false, the app will fire one of 2 procedures.  These are nearly identical.    One uses one dataset (clientdataset1) and the other users 2 datasets (clientdataset1 and clientdataset2)  I will only be using one at a time and never in the same session.  I personally have never used threads and get severely confused when reading about them as the verbage is unfamiliar to me.  the issues that would seem to be tough are teh dataset access and the reporting of status to the main form.  

Please give as detailed an answer as you can, although I appreciate that this is not an easy question.

Andrew
0
hibbidiji
Asked:
hibbidiji
1 Solution
 
__alexCommented:
0
 
Ivanov_GCommented:
if the DataSet from the first thread is one of the DataSets in the second thread ... you have to use CriticalSection...
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Ivanov_GCommented:
// THREAD EXAMPLE
// -----------------------------

TTestThread = class(TThread)
private
  LocalDataSet   : TClientDataSet;
public
  IsFinished     : Boolean;
  constructor Create(CreateSuspended : Boolean; DS : TClientDataSet);
  procedure Execute; override;
end;


constructor TTestThread.Create(CreateSuspended: Boolean;
  DS: TClientDataSet);
begin
  // create the thread
  inherited Create(CreateSuspended);
  // pass the dataset locally
  LocalDataSet := DS;
  // init
  IsFinished := False;
end;

procedure TTestThread.Execute;
begin
  inherited;
  // Access the DS here
  // do something with it here...

  IsFinished := True;
end;

// EXAMPLE HOW YOU CALL IT
// ----------------------------------

procedure TForm1.Button1Click(Sender: TObject);
var
  tr      : TTestThread;
begin
  tr := TTestThread.Create(False, ClientDataSet1);
  while not tr.IsFinished do
    Application.ProcessMessages;
end;
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vadim_tiCommented:
1)DataSets

i think better way is to work with 3 datasets

thread A: clientdataset1A
thread B: clientdataset1B and clientdataset2B

this way you do not need to use critical sections

2)reporting of status to the main form

you can use
   PostMessage(MainForm.Handle, YOUR_MESSAGE, wParam, lParam)



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hibbidijiAuthor Commented:
hard but not impossible. thanks!
0

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