Question

I am writing a program which will type a line of text in 5 second interval. Now, what I am trying to do is to add function which will type the text character by character with small spaces between each character. I am trying to use Thread.Sleep but I my program crashes, and I’m not sure why.

How to do this properly?

    private void Interval(object sender, EventArgs e)
    {
        if (cbPause.Checked == false)
        {
            SendKeys.Send(txtText.Text + "{enter}");

            if (tbType.SelectedTab == tbInterval) tmrInterval.Interval = int.Parse(nudInterval.Value.ToString());
            if (tbType.SelectedTab == tbRange) tmrInterval.Interval = random.Next(int.Parse(nudMin.Value.ToString()), int.Parse(nudMax.Value.ToString()));
        }
        else if (cbPause.Checked == true)
        {
            Random random = new Random();

            foreach (char character in charList)
            {
                SendKeys.Send(character.ToString());
                Thread.Sleep(1000);
            }

            SendKeys.Send("{enter}");
        }
    }

    private void btnStart_Click(object sender, EventArgs e)
    {
        if (txtText.TextLength < 1 || txtText.Text == string.Empty)
        {
            lblMessage.Text = "You must type text to proceed!";
            btnStart.Enabled = false;
        }
        else
        {
            foreach (char character in txtText.Text)
            {
                charList.Add(character);
            }

            if (tbType.SelectedTab == tbInterval)
            {
                tmrDelay.Enabled = true;

                txtText.Enabled = false;
                nudInterval.Enabled = false;
                nudMin.Enabled = false;
                nudMax.Enabled = false;
                btnStart.Enabled = false;
                btnStop.Enabled = true;
            }

            if (tbType.SelectedTab == tbRange)
            {
                tmrDelay.Enabled = true;
                tbType.Enabled = false;
                txtText.Enabled = false;
                nudInterval.Enabled = false;
                nudMin.Enabled = false;
                nudMax.Enabled = false;
                btnStart.Enabled = false;
                btnStop.Enabled = true;
            }

            lblMessage.Text = "Starting auto typing in: 3";
        }
    }

Answer 1

If you call Thread.Sleep, this is going to hang your GUI thread.

What I would do, is use a System.Windows.Forms.Timer, and every Tick, have it type the next character.

public partial class Form1 : Form
{
    Timer timer;
    string str;
    int char_num;

    public Form1()
    {
        InitializeComponent();
        timer = new Timer();
        timer.Tick += timer_Tick;
    }

    void timer_Tick(object sender, EventArgs e)
    {
        SendKeys.Send(str.Substring(char_num++, 1));
        if (char_num == str.Length)
            timer.Stop();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        textBox1.Focus();
        str = "Jonathon";
        char_num = 0;
        timer.Interval = 1000;
        timer.Start();
    }
}

Note: If it’s not obvious, this code requires a form with a textBox1 and a button who’s Click event is wired to button1_Click().

If you want the first character to be sent right away, you can “cheat” by calling the Tick handler right away when you start the timer, by adding the following line:

timer_Tick(null, EventArgs.Empty);