Passing two paramaters

Passing two paramaters

• Vaish

  The second parameter you're passing with the ReportProgress method is a "user state" parameter, which can hold any type of object. If you pass an integer value through this parameter, you can retrieve its value like:

  progressBar1.Maximum = (int)e.UserState;

  However, if you need to pass even more parameters, you can create a class with a few properties you need and pass that. Then, in ProgressChanged handler, cast e.UserState to that class and read its properties.

  Andrej

  
  
  

• chaz1

  You would only start the second thread from the first thread's RunWorkerCompleted event, which will trigger when the first thread is finished processing.

  Andrej

  
  
  

• Oscarfh

  It works perfectly, thanks a lot.

  Russ

  
  

• Kannan.B

  Ok, I guess I should have figured that out.

  There is one more thing that I am trying to figure out, and I think that after that I am set with this program. Let's say that I have two classes:

  ghv_sql_res
  ghv_sql_res_2

  Now let's say that ghv_sql_res prepares all of my results, and then ghv_sql_res_2 then takes those results and writes them to my database. I need ghv_sql_res_2 to run only when ghv_sql_res has completed, and not at the same time. I tried to do the following, but that runs them simultaneously:

  ghv_sql_res sqlProcess = new ghv_sql_res();
  backgroundWorker = new BackgroundWorker();
  backgroundWorker.WorkerReportsProgress = true;
  backgroundWorker.DoWork += new DoWorkEventHandler(sqlProcess.ghv_sql_res_process);
  backgroundWorker.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker_ProgressChanged);
  backgroundWorker.RunWorkerAsync();

  ghv_sql_res_2 sqlProcess_2 = new ghv_sql_res_2();
  backgroundWorker = new BackgroundWorker();
  backgroundWorker.WorkerReportsProgress = true;
  backgroundWorker.DoWork += new DoWorkEventHandler(sqlProcess_2.ghv_sql_res_2_process);
  backgroundWorker.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker_ProgressChanged);
  backgroundWorker.RunWorkerAsync();

  If I wanted to tell my program to wait until the first class was done executing, would I use a sleep command, or is there part of the backgroundWorker component that would give these instructions more efficiently

  Thanks for all of your help, you've simplified everything greatly.

  Thanks,
  Russ

  
  

• cb3431

  BackgroundWorker also has RunWorkerCompleted event, which is triggered when your class is done processing. Run the first class. In its DoWork handler, return the results as a Result parameter. You can access this parameter in the RunWorkerCompleted event. Read the result here and trigger your second class.

  private void worker_DoWork(object sender, DoWorkEventArgs e)
  {
  // Do your work here
  e.Result = "return results which your next class will use";
  }

  private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
  {
  string result = (string)e.Result;
  // Pass this result as an entry parameter for processing your next class
  // In this case the result is a string, but it can be any other type
  }

  Andrej

  
  
  

• Fabrice MARGUERIE

  Ok, that works perfect, thank you so much.

  Another quick question, how do I pass a parameter to the child thread using the BackgroundWorker component

  Thanks,

  Russ

  
  

• Will Merydith

  Ok, that makes sense, but how is the best way to stop my second thread from triggering until that point. Am I to have it sleep with a loop

  Thanks,
  Russ

  
  

• Nikhil Vaghela

  You can pass a parameter with the RunWorkerAsync() method:

  worker.RunWorkerAsync(500);

  and read it in its DoWork event handler:

  void worker_DoWork(object sender, DoWorkEventArgs e)
  {
  int parameter = (int)e.Argument;
  }

  Andrej

  
  
  
• Passing two paramaters