Question

I would like to set a textbox text to “blink” by changing text colors when a button is clicked.

I can get the text to blink how I want it to, but I want it to stop after a few blinks. I cannot figure out how to make it stop after the timer fires a few times.

Here is my code:

public Form1()
{
    InitializeComponent();

    Timer timer = new Timer();
    timer.Interval = 500;
    timer.Enabled = false;

    timer.Start();
    timer.Tick += new EventHandler(timer_Tick);

    if (timerint == 5)
    timer.Stop();
}

private void timer_Tick(object sender, EventArgs e)
{
    timerint += 1;

    if (textBoxInvFooter.ForeColor == SystemColors.GrayText)
        textBoxInvFooter.ForeColor = SystemColors.Highlight;
    else
        textBoxInvFooter.ForeColor = SystemColors.GrayText;
}

I know my problem lies with how I’m using the “timerint”, but I’m not sure where to put it, or what solution I should use…

Thank you for all your help!

Answer 1

Here’s the complete code that I would use to solve your issue. It correctly stops the timer, detaches the event handler, and disposes the timer. It disables the button during the flashing, and also restores the colour of the textbox after the five flashes are complete.

The best part is that it is purely defined within the one lambda, so no class-level variables required.

Here it is:

        button1.Click += (s, e) =>
        {
            button1.Enabled = false;
            var counter = 0;
            var timer = new Timer()
            {
                Interval = 500,
                Enabled = false
            };

            EventHandler handler = null;
            handler = (s2, e2) =>
            {
                if (++counter >= 5)
                {
                    timer.Stop();
                    timer.Tick -= handler;
                    timer.Dispose();
                    textBoxInvFooter.ForeColor = SystemColors.WindowText;
                    button1.Enabled = true;
                }
                else
                {
                    textBoxInvFooter.ForeColor =
                        textBoxInvFooter.ForeColor == SystemColors.GrayText
                            ? SystemColors.Highlight 
                            : SystemColors.GrayText;
                }
            };

            timer.Tick += handler;
            timer.Start();
        };