CODEWITHSUNDEEP
c#multithreadingwinformsdatagridview
ainla
ainla

Reputation: 529

Multi-thread C# application with BindingList<T> and DataGridView

I have public static class MyGlobals for my application wide variables and multiple threads processing and changing these variables.

public static class MyGlobals
{
    public static BindingList<Device> devicesList;
    public static BindingList<Device> availableList;
    public static object listLock = new object();
}

I have one Timer thread, that updates part of the list (for example Device.status fields) and UI thread where these lists are binded to DataGridView tables and some of the fields (for example Device.description field) can be manually edited there.

My problem is that when Timer thread wants to update Binding list content then I get InvalidOperationException:

Additional information: Cross-thread operation not valid: Control 'gridView1' accessed from a thread other than the thread it was created on.

I use lock(listLock) statement around every code block where I modify MyGlogals lists, but I cannot control how DataGridView handles the lists. How to make this application thread safe?

Upvotes: 2

Views: 2402

Answers (2)

No Idea For Name
No Idea For Name

Reputation: 11577

you cannot update the UI thread from a different thread.

you can use this post to help you solve it: for example do

     foreach (Device device in MyGlobals.devicesList)
     {
        Invoke(new MethodInvoker(delegate {
             device.text = "newText";
        }));
     }

or use background worker:

     BackgroundWorker bg = new BackgroundWorker();
     bg.DoWork += new DoWorkEventHandler(bg_DoWork);
     bg.RunWorkerAsync();

and in bg_DoWork:

  void bg_DoWork(object sender, DoWorkEventArgs e)
  {
     foreach (Device device in MyGlobals.devicesList)
     {
           device.text = "newText";
     }
  }

Upvotes: 1

noelicus
noelicus

Reputation: 15055

The GUI itself needs to be updated from the GUI thread (main thread). .NET provides the BackgroundWorker class for just this purpose. Comms with the GUI can be done via either/or ProgressChanged and RunWorkerCompleted events, in which you can pass an object of choice (e.g. to be displayed).

Upvotes: 1

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