How to Get My C# Program to Sleep for 50 Msec

How do I get my C# program to sleep for 50 milliseconds?

System.Threading.Thread.Sleep(50);

Remember though, that doing this in the main GUI thread will block your GUI from updating (it will feel "sluggish")

Just remove the ; to make it work for VB.net as well.

Thread.Sleep for less than 1 millisecond

You can't do this. A single sleep call will typically block for far longer than a millisecond (it's OS and system dependent, but in my experience, Thread.Sleep(1) tends to block for somewhere between 12-15ms).

Windows, in general, is not designed as a real-time operating system. This type of control is typically impossible to achieve on normal (desktop/server) versions of Windows.

The closest you can get is typically to spin and eat CPU cycles until you've achieved the wait time you want (measured with a high performance counter). This, however, is pretty awful - you'll eat up an entire CPU, and even then, you'll likely get preempted by the OS at times and effectively "sleep" for longer than 1ms...

C# Sleep for 500 milliseconds

Hmya, what you're trying to do is pretty fundamentally incompatible with the Windows programming model. A native Windows program is event driven. Your program is always idle, sitting inside a loop started by Application.Run(), waiting for Windows to tell it that something interesting happened that it should respond to. Paint requests, mouse clicks, timer expirations, stuff like that.

Your program should respond to this and filter what is interesting to you. When you drop a button on a form, you are always interested in the Click event, generated when Windows sends the MouseDown notification message. Your Click event handler runs some kind of custom code that you write. Like updating a status bar message in your case.

Updating the status bar message half a second later doesn't make a whole heckofalot of sense. What exactly happened during those 500 milliseconds that changed the way your program responds to events? You can call the Update() method of the StatusBar so the new message is visible, then call System.Threading.Thread.Sleep(500) to get what you want. You'll get away with it, the "Not Responding" ghost that Windows puts up takes your program going dead for several seconds.

But that doesn't make a lot of sense, nothing happened during that half second, the state of your program didn't change. It couldn't change, it was dead to Windows and not receiving any messages that would allow it to change state.

Well, that's about as far as I can take this. Please update your question and explain why you need to do this. Just in case: if you're contemplating this to fake doing something important for half a second, your user will not be impressed. She'll eventually notice your UI is dead for half a second without anything to show for it.

How to delay program for a certain number of milliseconds, or until a key is pressed?

First sample is using Timer, ManuelResetEvent and Global Keyboard hook:

I did not include keyboard hook code because it's too large. You can find it here.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Threading;

namespace WindowsFormsApplication1
{
    static class Program
    {
        private static System.Threading.Timer _timer;
        private static ManualResetEvent _signal;

        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            _signal = new ManualResetEvent(false);

            _timer = new System.Threading.Timer(Timer_Signaled, null, 15000, 0);

            _signal.WaitOne();
            _signal.Reset();

            Application.Run(new Form1());
        }

        private static void Timer_Signaled(object state)
        {
            _signal.Set();
        }
    }
}

When you hook to keyboard and ESC is pressed, simply call: _signal.Set(). This first sample is just to give you an idea.

Second sample:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace WindowsFormsApplication1
{
    static class Program
    {

        [DllImport("user32.dll")]
        static extern short GetAsyncKeyState(System.Windows.Forms.Keys vKey);

        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            int maxWaitTime = 15000;

            int tc = System.Environment.TickCount;

            while (true)
            {
                System.Threading.Thread.Sleep(1000);

                if (System.Environment.TickCount - tc > maxWaitTime)
                {
                    break;
                }

                if (GetAsyncKeyState(Keys.Escape) > 0)
                {
                    break;
                }
            }

            Application.Run(new Form1());
        }
    }
}

EDITED:

First sample is more reliable as keyboard hook use callback to inform which key was pressed. Second sample works like 'Pull' and it can happen not every key press will be collected.

Wait one second in running program

Is it pausing, but you don't see your red color appear in the cell? Try this:

dataGridView1.Rows[x1].Cells[y1].Style.BackColor = System.Drawing.Color.Red;
dataGridView1.Refresh();
System.Threading.Thread.Sleep(1000);

Using Thread.Sleep, while using program

Run your method in separate thread, and you will be free to pause/resume as much as you want...

Take a look to the Thread class

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