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Hi.. Friends, I want to make a such type of application in which I can lock my computer using user name and password, in my c# window application, if user enter the correct username and password then computer will be unlock. I have no no idea about this, would you please help me?

Thanks & Regards in advance
Parveen Rathi
Posted 28-Feb-12 17:28pm
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Solution 2

First method, probably the simplest:

System.Diagnostics.Process.Start("Rundll32.exe", "User32dll,LockWorkStation");

See http://msdn.microsoft.com/en-us/library/h6ak8zt5.aspx[^].

Nearly the same, without running a child process, immediately from the calling process:

class LockIt {
   [System.Runtime.InteropServices.DllImport("user32.dll")]
   internal static extern void LockWorkStation();
}

That's is.

—SA
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Comments
Parveen Rathi at 29-Feb-12 1:10am
   
But how i unlock it again?
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Solution 1

Here is the sample windows application which does this task by using two APIs from user32.dll.

namespace Lock_Display
{
    static class Program
    {
        private const int WmSyscommand = 0x0112;
        private const int ScMonitorpower = 0xF170;
        private const int HwndBroadcast = 0xFFFF;
        private const int ShutOffDisplay = 2;
        [DllImport("user32.dll")]
        private static extern void LockWorkStation();
        [DllImport("user32.dll", SetLastError = true)]
        private static extern bool PostMessage(IntPtr hWnd, uint msg,
                      IntPtr wParam, IntPtr lParam);
        private static void TurnOffDisplay()
        {
            PostMessage((IntPtr)HwndBroadcast, (uint)WmSyscommand,
                    (IntPtr)ScMonitorpower, (IntPtr)ShutOffDisplay);
        }
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            LockWorkStation();
            TurnOffDisplay();
        }
    }
}
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Comments
SAKryukov at 29-Feb-12 0:43am
   
I do not understand why it's so complex. My two solutions work, my simpler. Want to see?
--SA
Parveen Rathi at 29-Feb-12 1:04am
   
Yes. my pleasure
Parveen Rathi at 29-Feb-12 1:07am
   
with this code I lock my computer and how can i unlock it again? and where I place your code?

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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