Search
Module:
Directory

   Desktop Functions:

   Smart Device Functions:


Show Recent Changes
Subscribe (RSS)
Misc. Pages
Comments
FAQ
Helpful Tools
Playground
Suggested Reading
Website TODO List
Download Visual Studio Add-In

keybd_event (user32)
 
.
Summary
The keybd_event API

C# Signature:

[DllImport("user32.dll")]
static extern void keybd_event(byte bVk, byte bScan, uint dwFlags,
   UIntPtr dwExtraInfo);

VB Signature:

<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

User-Defined Types:

None.

Notes:

None.

Tips & Tricks:

This function is usefull 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 chart) http://msdn2.microsoft.com/en-us/library/aa926323.aspx (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 );
    }

Sample Code:

VB Sample:

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, 0, 0, 0)               ' Generates a KEY_DOWN
        keybd_event(VK_SCROLL, 0, 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 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 alt key
    keybd_event(VK_LSHIFT, 0x45, KEYEVENTF_KEYUP, 0);

Please edit this page!

Do you have...

  • helpful tips or sample code to share for using this API in managed code?
  • corrections to the existing content?
  • variations of the signature you want to share?
  • additional languages you want to include?

Select "Edit This Page" on the right hand toolbar and edit it! Or add new pages containing supporting types needed for this API (structures, delegates, and more).

 
Access PInvoke.net directly from VS:
Terms of Use
Find References
Show Printable Version
Revisions