CODEWITHSUNDEEP
c#multithreadingui-thread
BennoDual
BennoDual

Reputation: 6279

Invoke on Control vs. Invoke on Form

For example I use the following code:

private void startCalculcationButton_Click(object sender, EventArgs e) {
    int number;
    if (int.TryParse(this.numberTextBox.Text, out number)) {
    this.calculationResultLabel.Text = "(computing)";
        Task.Factory.StartNew(() => {
            int result = LongCalculation(number);
            this.calculationResultLabel.BeginInvoke(new ThreadStart(() => {
                this.calculationResultLabel.Text = result.ToString();
            }));
        });
    }
}

There I call this.calculationResultLabel.BeginInvoke(...) to switch to the UI-Thread for setting the Result to the Label.

I could also use this.Invoke(...) (this is the Form). Does it make a difference internally?

Upvotes: 1

Views: 333

Answers (1)

user585968
user585968

Reputation:

Invoke on Control vs. Invoke on Form

I could also use this.Invoke(...) (this is the Form). Does it make a difference internally?

It sounds like you are asking two different things. Your title says Invoke but your code is using BeginInvoke but you seem to be also asking about whether to invoke on a form or control.

  1. It makes no difference whether you xxxInvoke to the form or a specific control. Both are UI elements and both can marshal calls for you.

  2. If you are asking about the difference between Invoke and BeginInvoke, two methods that can marshal a call to the UI thread via the message pump, there is a difference between them. Invoke can lead to thread deadlock whilst the latter won't.

Anyway, since you are using Task and that you update the UI immediately after the long running task, you are arguably better doing:

private void startCalculcationButton_Click(object sender, EventArgs e) {
    int number;
    if (int.TryParse(this.numberTextBox.Text, out number)) 
    {
        this.calculationResultLabel.Text = "(computing)"; // UI thread
        var result  = await Task.Run(() => 
                LongCalculation(number));  // threadpool thread

        calculationResultLabel.Text = result.ToString(); // UI thread
    }
}

No fiddly manual marshalling required via BeginInvoke or dangerous-to-use Invoke.

Upvotes: 1

Related Questions