threads communication

Question

I have a form with text box and button. On click of button I'm creating a thread and invoking it for some operation. once the thread completes the invoked task, I want to update the text box with the result.

any one please assist me how can I achieve this without thread clash.

Answer 1

This is far simpler using .NET 4.0's Task class:

private void button_Click(object sender, EventArgs e)
{
    Task.Factory.StartNew( () => 
    {
         return DoSomeOperation();
    }).ContinueWith(t =>
    {
         var result = t.Result;
         this.textBox.Text = result.ToString(); // Set your text box
    }, TaskScheduler.FromCurrentSynchronizationContext());
}

If you're using .NET 4.5, you can simplify this further using the new async support:

private async void button_Click(object sender, EventArgs e)
{
    var result = await Task.Run( () => 
    {
         // This runs on a ThreadPool thread 
         return DoSomeOperation();
    });

    this.textBox.Text = result.ToString();
}

Answer 2

You need to use Control.Invoke to manipulate your form in it's own thread.

Answer 3

Simply, at the end of the thread operation:

/// ... your code here
string newText = ...

textBox.Invoke((MethodInvoker) delegate {
    textBox.Text = newText;
});

The Control.Invoke usage uses the message-queue to hand work to the UI thread, so it is the UI thread that executes the textBox.Text = newText; line.

Answer 4

Use a BackgroundWorker, assign the task to the DoWork event, and update the text box with the RunWorkerCompleted event. Then you can start the task with RunWorkerAsync().

Answer 5

You can use the solutions showed here:

How to update the GUI from another thread in C#?

Next time search a bit before asking.