CODEWITHSUNDEEP
c#.netasynchronousasync-awaittask-parallel-library
Hemanth Krishna
Hemanth Krishna

Reputation: 76

How to Fix Cross-thread error When using Task Parallel library?

 List<Task> tasks = new List<Task>();
 tasks.Add(Task.Run(() => functionA()));
 tasks.Add(Task.Run(() => functionB()));
 tasks.Add(Task.Run(() => functionC()));



 function A(){
  List<string>lstResult =Get list ();
  control.DataSource =lstResult ;
  control.Databind();
  }



   function B(){
     List<string>lstResult =Get list ();
     control.DataSource =lstResult ;
     control.Databind();
   }



   function C(){
    List<string>lstResult =Get list ();
    control.DataSource =lstResult ;
    control.Databind();
    }

Here, I am getting Stack Empty exception because of concurrency Issue. How to solve this one. I came across this one Stack Empty Excetpion but nowhere it is mentioned how to overcome this issue.

Upvotes: 0

Views: 403

Answers (2)

Panagiotis Kanavos
Panagiotis Kanavos

Reputation: 131712

You can't modify the UI from another thread, in any operating system. This code can be simplified a lot if async/await is used and Task.Run moves inside the functions, eg :

async Task functionA(){
    var results= await Task.Run(()=>Getlist1();
    control1.DataSource =results ;
    control1.Databind();
}

async Task functionB(){
    var results= await Task.Run(()=>Getlist2();
    control2.DataSource =results ;
    control2.Databind();
}

async Task functionC(){
    var results= await Task.Run(()=>Getlist3();
    control3.DataSource =results ;
    control3.Databind();
}


var tasks = await Task.WhenAll( functionA(),
                                functionB(),
                                functionC());

await awaits for an already asynchronous operation to complete without blocking. When that operation completes, it returns execution to the original thread, in this case the UI thread

Upvotes: 3

koviroli
koviroli

Reputation: 1453

Your control object can be accessed by multiple threads at the same time. To solve this issue, you have to use MethodInvoker like this:

function A(){
    List<string> lstResult =Getlist();
    Invoke(new MethodInvoker(delegate
    {
        control.DataSource =lstResult ;
        control.Databind();
    }));
}

Upvotes: 0

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