CODEWITHSUNDEEP
c#wpfmultithreadingdatagridtimeout
Babak.Abad
Babak.Abad

Reputation: 2956

Updating DataGrid from multiple threads

I want to update my a DataGrid from multiple thread in WPF(c#). I use dataGrid.Dispatcher.BeginInvoke() and dataGrid.Dispatcher.Invoke() but they freeze program (main thread). How can update dataGrid from multiple threads with a timeout ( because I use web service that may be unreachable ).

Upvotes: 1

Views: 1189

Answers (2)

Brian Gideon
Brian Gideon

Reputation: 48949

Use a Task kick off the web service request asynchronously. To do this you will probably need to convert the EAP (event-based asynchronous pattern) style into a TAP (task-based asynchronous pattern) style. Here is how you do that.

private Task<IEnumerable<YourDataItem>> CallWebServiceAsync()
{
  var tcs = new TaskCompletionSource();
  var service = new YourServiceClient();
  service.SomeOperationCompleted +=
    (sender, args) =>
    {
      if (args.Error == null)
      {
        tcs.SetResult(args.Result);
      }
      else
      {
        tcs.SetException(args.Error);
      }
    };
  service.SomeOperationAsync();
  return tcs.Task;
}

After you have that in place then you can use the new async and await keywords to make the call and wait for it to return using continuation style semantics. It would look like this.

private async void Page_Loaded(object sender, System.Windows.RoutedEventArgs e)
{
  IEnumerable<YourDataItem> data = await CallWebServiceAsync();
  YourDataGrid.DataSource = data;
}

That is it! It does not get a whole lot more elegant than that. This will perform the operation asynchronously on a background thread and then bind the results to the DataGrid on the UI thread.

If the WCF service is unreachable then it will throw an exception and will be attached to the Task so that it propagates up to the await call. At that point it will be injected into the execution and can be wrapped with a try-catch if necessary.

Upvotes: 3

Prime
Prime

Reputation: 2482

If you don't need the DataGrid editing to be done in the threads, you can run them in the main thread like this:

this.Invoke((Action)delegate
{
    //Edit the DataGrid however you like in here
});

Make sure to only put things you need to be run in the main thread inside it (otherwise that would defeat the purpose of multithreading).

Upvotes: 1

Related Questions