pinvoke.net: Edit: user32.keybd

@msdn=http://search.microsoft.com/search/results.aspx?qu=$$$
@pinvoke=http://pinvoke.net/$$$.htm

Summary: This function is useful to simulate Key presses to the window with focus.
!!!!C# Signature:
 [DllImport("user32.dll")]
 static extern void keybd_event(byte bVk, byte bScan, uint dwFlags,
   UIntPtr dwExtraInfo);
or
 [DllImport("user32.dll")]
 static extern void keybd_event(byte bVk, byte bScan, uint dwFlags,
   int dwExtraInfo);

!!!!VB.NET Signature:
 <DllImport("user32.dll")> _
 Private Shared Sub keybd_event(bVk As Byte, bScan As Byte, dwFlags As UInteger, dwExtraInfo As UIntPtr)
 End Function
or
 <DllImport("user32.dll")> _
 Private Shared Sub keybd_event(bVk As Byte, bScan As Byte, dwFlags As UInteger, dwExtraInfo As Integer)
 End Function
or
 <DllImport("user32.dll", CallingConvention:=CallingConvention.StdCall, _
               CharSet:=CharSet.Unicode, EntryPoint:="keybd_event", _
               ExactSpelling:=True, SetLastError:=True)> _
 Public Shared Sub keybd_event(ByVal bVk As Byte, ByVal bScan As Byte, _
							  ByVal dwFlags As Int32, ByVal dwExtraInfo As Int32)
 End Function

!!!!VB Signature:
 Public Declare Sub keybd_event Lib "user32" (ByVal bVk As Byte, ByVal bScan As Byte, ByVal dwFlags As Long, ByVal dwExtraInfo As Long)

!!!!User-Defined Constants:
C#:
 const uint KEYEVENTF_EXTENDEDKEY = 0x0001;
 const uint KEYEVENTF_KEYUP = 0x0002;
VB.NET:
 Const KEYEVENTF_EXTENDEDKEY As UInteger = &H1
 Const KEYEVENTF_KEYUP As UInteger = &H2

VKs
http://msdn.microsoft.com/en-us/library/windows/desktop/dd375731(v=vs.85).aspx

!!!!User-Defined Types:
None
!!!!Notes:
None.

!!!!Tips & Tricks:
This function is useful to simulate Key presses (for input use the virtual keycodes from http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/WinUI/WindowsUserInterface/UserInput/VirtualKeyCodes.asp or windows CE universal core virtual key code compact chart http://msdn2.microsoft.com/en-us/library/ms927178.aspx ).  
Use FindWindow and SetForegroundWindow to direct input to the desired window. 
Note: WaitForInputIdle (Warning this will only wait once! See Raymond Chen's Blog Post http://blogs.msdn.com/b/oldnewthing/archive/2010/03/25/9984720.aspx ), or a Sleep may be required to assure Window is ready for input:
  RUN('NOTEPAD.EXE')
  Sleep(2000,0)
  SetForegroundWindow (FindWindow('Untitled - Notepad'))
(see also VkKeyScan):

void PressKey( byte keyCode )
        {
            const int KEYEVENTF_EXTENDEDKEY = 0x1;
            const int KEYEVENTF_KEYUP       = 0x2;
            keybd_event( keyCode, 0x45, KEYEVENTF_EXTENDEDKEY, 0 );
            keybd_event( keyCode, 0x45, KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP, 0 );
        }

!!!!C# Sample Code
 // Sends ENTER button press event in focused window
 
 using System;
 using System.Collections.Generic;
 using System.Drawing;
 using System.Text;
 using System.Windows.Forms;
 
 using System.Runtime.InteropServices;
 using System.Threading;
 
 namespace PInvoke_DllImport_Cs
 {
     public partial class Form1 : Form
     {
         public Form1()
         {
             InitializeComponent();
         }
 
         const byte VK_RETURN = 0x0D;
 
         const uint KEYEVENTF_KEYUP = 0x0002;
 
         [DllImport("user32.dll")]
         private static extern void keybd_event(byte bVk, byte bScan, uint dwFlags, int dwExtraInfo);
 
         private void timer1_Tick(System.Object sender, System.EventArgs e)
         {
             keybd_event(VK_RETURN, 0, 0, 0);
             Thread.Sleep(100);
             keybd_event(VK_RETURN, 0, KEYEVENTF_KEYUP, 0);
         }
     }
 }

!!!!VB.NET Sample Code 1
 ' Sends ENTER button press event in focused window
 
 Imports System.Runtime.InteropServices
 Imports System.Threading
 
 Public Class Form1
 
     Const VK_RETURN As Byte = &HD '0x0D
 
     Const KEYEVENTF_KEYUP As UInteger = &H2 '0x0002
 
     <DllImport("user32.dll")> _
     Private Shared Sub keybd_event(ByVal bVk As Byte, ByVal bScan As Byte, ByVal dwFlags As UInteger, ByVal dwExtraInfo As Integer)
     End Function
 
     'Public Declare Sub keybd_event Lib "user32" (ByVal bVk As Byte, ByVal bScan As Byte, ByVal dwFlags As Long, ByVal dwExtraInfo As Long)
 
     Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
         keybd_event(VK_RETURN, 0, 0, 0)
         Thread.Sleep(100)
         keybd_event(VK_RETURN, 0, KEYEVENTF_KEYUP, 0)
     End Sub
 
 End Class

!!!!VB.NET Sample Code 2:
This sample will generate a 'Scroll Lock' key press event when the user clicks 'Button1'.
	*Create a new Windows Application project;
	*Drop a button control in the recently created form;
	*Add the following code to the form class:
 Imports System.Runtime.InteropServices

Public Class Form1

<DllImport("user32.dll", CallingConvention:=CallingConvention.StdCall, _
               CharSet:=CharSet.Unicode, EntryPoint:="keybd_event", _
               ExactSpelling:=True, SetLastError:=True)> _
    Public Shared Sub keybd_event(ByVal bVk As Byte, ByVal bScan As Byte, _
                                                              ByVal dwFlags As Integer, ByVal dwExtraInfo As Integer)
    End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Const VK_SCROLL As Byte = &H91
            Const KEYEVENTF_KEYUP As Byte = &H2

keybd_event(VK_SCROLL, 0x45, 0, 0)                       ' Generates a KEY_DOWN
            keybd_event(VK_SCROLL, 0x45, KEYEVENTF_KEYUP, 0) ' Generates a KEY_UP

End Sub

End Class

Please add some more!

!!!!Alternative Managed API: '''System.Windows.Forms.SendKeys'''

Documentation: keybd_event@msdn on MSDN

!!!!PROBLEM: How do i use combination of shift and tab keys at the same time ?

!!!!Answer:posted by dokks http://www.ravensmyst.com

define the shift key as a const

public const byte VK_LSHIFT= 0xA0; // left shift key
	public const byte VK_TAB = 0x09;
	public const int KEYEVENTF_EXTENDEDKEY = 0x01;
	public const int KEYEVENTF_KEYUP = 0x02;

//press the shift key
	keybd_event(VK_LSHIFT, 0x45, 0, 0);

//press the tab key
	keybd_event(VK_TAB, 0x45, 0, 0);

//release the tab key
	keybd_event(VK_TAB, 0x45, KEYEVENTF_KEYUP, 0);

//release the shift key
	keybd_event(VK_LSHIFT, 0x45, KEYEVENTF_KEYUP, 0);

I'm using this to create automated UI testing for a custom Textbox control. After a lot of trial and error the following code worked well for me.

public partial class Form2 : Form
    {
        [DllImport("user32.dll", SetLastError = true)]
        static extern void keybd_event(byte bVk, byte bScan, uint dwFlags, UIntPtr dwExtraInfo);

Keys[] numberKeys = new Keys[10] { Keys.D0, Keys.D1, Keys.D2, Keys.D3, Keys.D4, Keys.D5, Keys.D6, Keys.D7, Keys.D8, Keys.D9 };

void PressKey(Keys key)
        {
            const int KEYEVENTF_EXTENDEDKEY = 0x1;
            const int KEYEVENTF_KEYUP = 0x2;
		// I had some Compile errors until I Casted the final 0 to UIntPtr like this...
            keybd_event((byte)key, 0x45, KEYEVENTF_EXTENDEDKEY, (UIntPtr)0);
            keybd_event((byte)key, 0x45, KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP, (UIntPtr)0);
        }

void PressKeyArray(Keys[] keys)
        {
            foreach (Keys key in keys)
            {
                PressKey(key);
            }
        }

private void Compare(object sender, string expected, string actual)
        {
            Button ClickedButton = (Button)sender;

if (expected == actual)
                ClickedButton.Text = "Pass";
            else
                ClickedButton.Text = "Fail";
        }

private void buttonNumericAccept_Click(object sender, EventArgs e)
        {
            string expected = "0123456789";

NumericTextbox.AcceptNumeric = true;

//
            // Send Appropriate Key Presses
            //
            NumericTextbox.Focus();
            PressKeyArray(numberKeys);
            Application.DoEvents();

// Process Results            
            Compare(sender, expected, NumericTextbox.Text);            
	}
    }