Change button color for a short time

Question

I would like to change the backgroundcolor of a button for a couple of seconds to lime and then change it back to normal. For some reason it simply doesnt work, I have to wait for those seconds and some things I tested also work but the backgroundcolor isn't changed. This is what I've tried so far:

private void button1_Click(object sender, EventArgs e)
{
    button1.BackColor = Color.Lime;
    Thread.Sleep(2000);
    button1.BackColor = SystemColors.Control;
}

Hopefully someone can help me out with this!

Answer 1

Or you could use a Storyboard if you're working with a XAML technology. I ain't posting implementation details, since they may vary depending on the target technology.

Answer 2

You need a timer. Add a timer control from the toolbox to your form. Double-click on it to add a timer tick event handler

    private void button1_Click(object sender, EventArgs e)
    {
        button1.BackColor = Color.Lime;
        //Set time between ticks in miliseconds.
        timer1.Tick=2000;
        //Start timer, your program continues execution normaly
        timer1.Start;
        //If you use sleep(2000) your program stop working for two seconds.

    }
        //this event will rise every time set in Tick (from start to stop)
        private void timer1_Tick(object sender, EventArgs e)
        {
          //When execution reach here, it means 2 seconds have passed. Stop timer and change color
          timer1.Stop;
          button1.BackColor = SystemColors.Control;
        }

Answer 3

As Horaciux mentioned, you can make use of a Timer object to do this.

Alternatively, you can make use of await and Task.Delay, as mentioned by Jon Skeet in this answer.

private async void button1_Click(object sender, EventArgs e)
{
    button1.BackColor = Color.Lime;
    await Task.Delay(2000);
    button1.BackColor = SystemColors.Control;

}

The problem with Thread.Sleep is that it is a blocking operation - in that it will stop anything happening on the thread in question. There are other issues too though - chiefly that Thread.Sleep doesn't guarantee reactivating the thread in the time specified. When you execute Thread.Sleep, you are basically telling the CPU that your thread doesn't need to be active for the time specified - however, the CPU only guarantees that it won't process it for that time - it doesn't guarantee that it will reactivate at that time, merely at some point after the sleep period (once it has finished processing any other threads currently active).

Since you are adding Thread.Sleep to your UI thread, you are effectively locking up the entire application for the duration of the sleep. await Task.Delay on the other hand, won't block the thread, but will return to that line of code in the function once the task in the await has completed (in this case, a Delay action). This allows all other methods to continue to operate as normal (button clicks will work fine, etc). This method has the added advantage of keeping all the relevant code in one place, rather than having part of it in a different method.