CODEWITHSUNDEEP
c#winforms
Hotkey
Hotkey

Reputation: 450

Timer with Enabled value true does not work when using in WinFormAnimation

I'm trying to make System.Windows.Forms.Timer to work after animation.

private Timer timer1 = new Timer();

protected override void OnLoad(EventArgs e)
{
    timer1.Interval = 25;
    timer1.Tick += timer1_Tick;

    tempX = this.Location.X;
    new Animator2D(new Path2D(-300, 23, this.Location.Y, this.Location.Y, 1500, AnimationFunctions.ExponentialEaseOut))
    .Play(this, Animator2D.KnownProperties.Location, new SafeInvoker((() =>
    {
        timer1.Enabled = true;
    })));

    base.OnLoad(e);
}

I use this method. But it doesn't work

So I changed method like this.

private Timer timer1 = new Timer();

protected override void OnLoad(EventArgs e)
{
    timer1.Interval = 25;
    timer1.Tick += timer1_Tick;

    tempX = this.Location.X;
    new Animator2D(new Path2D(-300, 23, this.Location.Y, this.Location.Y, 1500, AnimationFunctions.ExponentialEaseOut))
    .Play(this, Animator2D.KnownProperties.Location, new SafeInvoker((() =>
    {
        Invoke(new Action(() => timer1.Enabled = true));
    })));

    base.OnLoad(e);
}

It work.

I don't know the difference between the methods.
Through the debugger, timer1's Enabled value is changed to True even when using the first method.

I wonder why this happens.

Upvotes: 1

Views: 389

Answers (1)

Fabjan
Fabjan

Reputation: 13676

Explanation:

This happens because method Invoke runs the code on the same thread context as control's underlying thread (which is the UI Thread in our case). Think of context as the current state of the thread and how it views memory at a specific time.

So when we don't use Invoke it is likely that the code runs on a different thread which also contains timer1. The code sets Enabled property to true there in that specific thread's context. Think of it as though you have two Timers instead of one - one in say thread A and another one in thread B.

Conclusion:

In order to avoid this mess we should always use Invoke when we need to update fields or properties in our Form while working in multi-threaded environment.

Upvotes: 1

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