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SendInput (user32)
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The SendInput function synthesizes keystrokes, mouse motions, and button clicks to the currently active window
<DllImport("user32.dll", SetLastError=true)> _
Private Shared Function SendInput(ByVal nInputs As Integer, ByRef pInputs As INPUT, byval cbSize As Integer) As Integer
End Function
Private Declare Function SendInput Lib "user32.dll" (ByVal cInputs As Integer, ByRef pInputs As INPUT, ByVal cbSize As Integer) As Integer
C# User-Defined Types:
struct MOUSEINPUT
{
public int dx;
public int dy;
public uint mouseData;
public uint dwFlags;
public uint time;
public IntPtr dwExtraInfo;
}
struct KEYBDINPUT
{
public ushort wVk;
public ushort wScan;
public uint dwFlags;
public uint time;
public IntPtr dwExtraInfo;
}
struct HARDWAREINPUT
{
public uint uMsg;
public ushort wParamL;
public ushort wParamH;
}
[StructLayout(LayoutKind.Explicit)]
struct MOUSEKEYBDHARDWAREINPUT
{
[FieldOffset(0)]
public MOUSEINPUT mi;
[FieldOffset(0)]
public KEYBDINPUT ki;
[FieldOffset(0)]
public HARDWAREINPUT hi;
}
struct INPUT
{
public int type;
public MOUSEKEYBDHARDWAREINPUT mkhi;
}
Private Structure INPUT
Dim dwType As Integer
Dim mkhi as MOUSEKEYBDHARDWAREINPUT
End Structure
Private Structure KEYBDINPUT
Public wVk As Short
Public wScan As Short
Public dwFlags As Integer
Public time As Integer
Public dwExtraInfo As IntPtr
End Structure
Private Structure HARDWAREINPUT
Public uMsg As Integer
Public wParamL As Short
Public wParamH As Short
End Structure
<StructLayout(LayoutKind.Explicit)> _
Private Structure MOUSEKEYBDHARDWAREINPUT
<FieldOffset(0)> Public mi As MOUSEINPUT
<FieldOffset(0)> Public ki As KEYBDINPUT
<FieldOffset(0)> Public hi As HARDWAREINPUT
End Structure
Private Structure MOUSEINPUT
Public dx As Integer
Public dy As Integer
Public mouseData As Integer
Public dwFlags As Integer
Public time As Integer
Public dwExtraInfo As IntPtr
End Structure
Notes:
You'll need some constants to use this function. Here they are.
/*
* VK_L* & VK_R* - left and right Alt, Ctrl and Shift virtual keys.
* Used only as parameters to GetAsyncKeyState() and GetKeyState().
* No other API or message will distinguish left and right keys in this way.
*/
VK_LSHIFT = 0xA0,
VK_RSHIFT = 0xA1,
VK_LCONTROL = 0xA2,
VK_RCONTROL = 0xA3,
VK_LMENU = 0xA4,
VK_RMENU = 0xA5,
/*
* 0xB8 - 0xB9 : reserved
*/
VK_OEM_1 = 0xBA, // ';:' for US
VK_OEM_PLUS = 0xBB, // '+' any country
VK_OEM_COMMA = 0xBC, // ',' any country
VK_OEM_MINUS = 0xBD, // '-' any country
VK_OEM_PERIOD = 0xBE, // '.' any country
VK_OEM_2 = 0xBF, // '/?' for US
VK_OEM_3 = 0xC0, // '`~' for US
/*
* 0xC1 - 0xD7 : reserved
*/
/*
* 0xD8 - 0xDA : unassigned
*/
VK_OEM_4 = 0xDB, // '[{' for US
VK_OEM_5 = 0xDC, // '\|' for US
VK_OEM_6 = 0xDD, // ']}' for US
VK_OEM_7 = 0xDE, // ''"' for US
VK_OEM_8 = 0xDF
/*
* 0xE0 : reserved
*/
}
Tips & Tricks:
Big GOTCHA: It is very unclear from Microsoft's documentation, but if you use a VK_ code, and that code represents a key that is an "Extended" key, you can get some strange responses. Things won't work for odd reasons. But, a line like:
if ((x >= 33 && x <= 46) || (x >= 91 && x <= 93)) ki.dwFlags += KEYEVENTF_EXTENDEDKEY;
will fix this. The affected keys are identifiable by E0 in the scan code. This is true even though scan codes and VK_ enumeration codes are different! It is the key that makes the difference. You have to declare it "extended" as in the code line above.
Another GOTCHA: Characters appear in text boxes just fine. BUT, if you want to send control codes such as <ctl>C, the system converts the unicode character to a packet and it will not work. In this case, you have to use "real" scan codes with appropriate modifier keys.
Sample Code: WARNING: The C# code will not compile due to numerous errors.
// It might be better to write this code as a single call to SendInput passing
// all the key downs and keys ups in one array. If you do this, SendInput
// guarantees that no other keys get inbetween the whole sequence. As is stands,
// a "real" key transition could in theory sneak in the middle - and if it did
// it would inherit the states of shift, control, etc this program had set up.
class Test
{
public enum VK : ushort
{
SHIFT = 0x10,
CONTROL = 0x11,
MENU = 0x12,
ESCAPE = 0x1B,
BACK = 0x08,
TAB = 0x09,
RETURN = 0x0D,
PRIOR = 0x21,
NEXT = 0x22,
END = 0x23,
HOME = 0x24,
LEFT = 0x25,
UP = 0x26,
RIGHT = 0x27,
DOWN = 0x28,
SELECT = 0x29,
PRINT = 0x2A,
EXECUTE = 0x2B,
SNAPSHOT = 0x2C,
INSERT = 0x2D,
DELETE = 0x2E,
HELP = 0x2F,
NUMPAD0 = 0x60,
NUMPAD1 = 0x61,
NUMPAD2 = 0x62,
NUMPAD3 = 0x63,
NUMPAD4 = 0x64,
NUMPAD5 = 0x65,
NUMPAD6 = 0x66,
NUMPAD7 = 0x67,
NUMPAD8 = 0x68,
NUMPAD9 = 0x69,
MULTIPLY = 0x6A,
ADD = 0x6B,
SEPARATOR = 0x6C,
SUBTRACT = 0x6D,
DECIMAL = 0x6E,
DIVIDE = 0x6F,
F1 = 0x70,
F2 = 0x71,
F3 = 0x72,
F4 = 0x73,
F5 = 0x74,
F6 = 0x75,
F7 = 0x76,
F8 = 0x77,
F9 = 0x78,
F10 = 0x79,
F11 = 0x7A,
F12 = 0x7B,
OEM_1 = 0xBA, // ',:' for US
OEM_PLUS = 0xBB, // '+' any country
OEM_COMMA = 0xBC, // ',' any country
OEM_MINUS = 0xBD, // '-' any country
OEM_PERIOD = 0xBE, // '.' any country
OEM_2 = 0xBF, // '/?' for US
OEM_3 = 0xC0, // '`~' for US
MEDIA_NEXT_TRACK = 0xB0,
MEDIA_PREV_TRACK = 0xB1,
MEDIA_STOP = 0xB2,
MEDIA_PLAY_PAUSE = 0xB3,
LWIN =0x5B,
RWIN =0x5C
}
public struct KEYBDINPUT
{
public ushort wVk;
public ushort wScan;
public uint dwFlags;
public long time;
public uint dwExtraInfo;
};
[StructLayout(LayoutKind.Explicit,Size=28)]
public struct INPUT
{
public uint type;
public KEYBDINPUT ki;
};
// Key down shift, ctrl, and/or alt
structInput.mkhi.ki.wScan = 0;
structInput.mkhi.ki.time = 0;
structInput.mkhi.ki.dwFlags = 0;
if (Shift)
{
structInput.mkhi.ki.wVk = (ushort)VK.SHIFT;
intReturn = Win32.SendInput(1, ref structInput, (UInt32)sizeof(INPUT));
}
if (Ctrl)
{
structInput.mkhi.ki.wVk = (ushort)VK.CONTROL;
intReturn = Win32.SendInput(1, ref structInput, (UInt32)sizeof(INPUT));
}
if (Alt)
{
structInput.mkhi.ki.wVk = (ushort)VK.MENU;
intReturn = Win32.SendInput(1, ref structInput, (UInt32)sizeof(INPUT));
}
if (Win)
{
structInput.mkhi.ki.wVk = (ushort)VK.LWIN;
intReturn = Win32.SendInput(1, ref structInput, (UInt32)sizeof(INPUT));
}
// Key down the actual key-code
structInput.mkhi.ki.wVk = vk;
intReturn = Win32.SendInput(1, ref structInput, (UInt32)sizeof(INPUT));
// Key up the actual key-code
structInput.mkhi.ki.dwFlags = Win32Consts.KEYEVENTF_KEYUP;
intReturn = Win32.SendInput(1, ref structInput, (UInt32)sizeof(INPUT));
// Key up shift, ctrl, and/or alt
if (Shift)
{
structInput.mkhi.ki.wVk = (ushort)VK.SHIFT;
intReturn = Win32.SendInput(1, ref structInput, (UInt32)sizeof(INPUT));
}
if (Ctrl)
{
structInput.mkhi.ki.wVk = (ushort)VK.CONTROL;
intReturn = Win32.SendInput(1, ref structInput, (UInt32)sizeof(INPUT));
}
if (Alt)
{
structInput.mkhi.ki.wVk = (ushort)VK.MENU;
intReturn = Win32.SendInput(1, ref structInput, (UInt32)sizeof(INPUT));
}
if (Win)
{
structInput.mkhi.ki.wVk = (ushort)VK.LWIN;
intReturn = Win32.SendInput(1, ref structInput, (UInt32)sizeof(INPUT));
}
}
}
VB.NET Sample Code:
Imports System.Runtime.InteropServices
Public Class Form1
Private tb As New TextBox
Private WithEvents but1 As New Button
Sub New()
InitializeComponent()
tb = New TextBox : tb.Location = New Point(10, 10)
but1 = New Button : but1.Location = New Point(10, 40)
but1.Text = "example"
Me.Controls.Add(but1) : Me.Controls.Add(tb)
End Sub
Private Sub DoMouse(ByVal flags As NativeMethods.MOUSEEVENTF, ByVal newPoint As Point)
Dim input As New NativeMethods.INPUT
Dim mi As New NativeMethods.MOUSEINPUT
input.dwType = NativeMethods.InputType.Mouse
input.mkhi.mi = mi
input.mkhi.mi.dwExtraInfo = IntPtr.Zero
' mouse co-ords: top left is (0,0), bottom right is (65535, 65535)
' convert screen co-ord to mouse co-ords...
input.mkhi.mi.dx = newPoint.X * (65535 / Screen.PrimaryScreen.Bounds.Width)
input.mkhi.mi.dy = newPoint.Y * (65535 / Screen.PrimaryScreen.Bounds.Height)
input.mkhi.mi.time = 0
input.mkhi.mi.mouseData = 0 ' can be used for WHEEL event see msdn
input.mkhi.mi.dwFlags = flags
Dim cbSize As Integer = Marshal.SizeOf(GetType(NativeMethods.INPUT))
Dim result As Integer = NativeMethods.SendInput(1, input, cbSize)
If result = 0 Then Debug.WriteLine(Marshal.GetLastWin32Error)
End Sub
Private Sub DoKeyBoard(ByVal flags As NativeMethods.KEYEVENTF, ByVal key As Keys)
Dim input As New NativeMethods.INPUT
Dim ki As New NativeMethods.KEYBDINPUT
input.dwType = NativeMethods.InputType.Keyboard
input.mkhi.ki = ki
input.mkhi.ki.wVk = Convert.ToInt16(key)
input.mkhi.ki.wScan = 0
input.mkhi.ki.time = 0
input.mkhi.ki.dwFlags = flags
input.mkhi.ki.dwExtraInfo = IntPtr.Zero
Dim cbSize As Integer = Marshal.SizeOf(GetType(NativeMethods.INPUT))
Dim result As Integer = NativeMethods.SendInput(1, input, cbSize)
If result = 0 Then Debug.WriteLine(Marshal.GetLastWin32Error)
End Sub
Private Sub but1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles but1.Click
'move to the textbox, click it to focus, keydown some chars...
' get textbox location in screen co-ords
Dim tbLocation As Point = Me.PointToScreen(Me.tb.Location)
' nudge it into the tb
tbLocation.X += 5
tbLocation.Y += 5
' move to the TB. it is a MOVE event, and we use ABSOLUTE co-ordinates
DoMouse(NativeMethods.MOUSEEVENTF.MOVE Or NativeMethods.MOUSEEVENTF.ABSOLUTE, tbLocation)
' click the TB
DoMouse(NativeMethods.MOUSEEVENTF.LEFTDOWN, New Point(0, 0))
' release the mouse
DoMouse(NativeMethods.MOUSEEVENTF.LEFTUP, New Point(0, 0))
' the key codes are virtual keycodes (see mdsn)
' I'm using a shortcut to save space - casting chars to ints
' if you want to change case, you need to send a shift key with the letter...
' sbq: I found the routine VkKeyScanA very helpful converting from
' characters to virtual key codes. Look it up in the MSDN. I declared it
' as shown below. It returns the key code in the low byte and the additional
' keys to be pressed while transmitting in the upper byte (e.g., shift, ctrl, alt):
'
' Private Declare Function VkKeyScanA Lib "user32" Alias "VkKeyScanA" (ByVal cChar_Renamed As Byte) As Short
'
Dim message As String = "HELLO WORLD"
For Each c As Char In message
Dim key As UInteger = Convert.ToInt16(c)
DoKeyBoard(0, key) ' key down is 0 - no flag...
DoKeyBoard(NativeMethods.KEYEVENTF.KEYUP, key)
Next
DoKeyBoard(0, Keys.Decimal) ' example using keys enum which I think matches the VKEY values
DoKeyBoard(NativeMethods.KEYEVENTF.KEYUP, Keys.Decimal)
End Sub
End Class
Public Class NativeMethods
<DllImport("user32.dll", SetLastError:=True)> _
Friend Shared Function SendInput(ByVal cInputs As Int32, ByRef pInputs As INPUT, ByVal cbSize As Int32) As Int32
End Function
<StructLayout(LayoutKind.Explicit, pack:=1, Size:=28)> _
Friend Structure INPUT
<FieldOffset(0)> Public dwType As InputType
<FieldOffset(4)> Public mi As MOUSEINPUT
<FieldOffset(4)> Public ki As KEYBDINPUT
<FieldOffset(4)> Public hi As HARDWAREINPUT
End Structure
<StructLayout(LayoutKind.Sequential, pack:=1)> _
Friend Structure MOUSEINPUT
Public dx As Int32
Public dy As Int32
Public mouseData As Int32
Public dwFlags As MOUSEEVENTF
Public time As Int32
Public dwExtraInfo As IntPtr
End Structure
<StructLayout(LayoutKind.Sequential, pack:=1)> _
Friend Structure KEYBDINPUT
Public wVk As Int16
Public wScan As Int16
Public dwFlags As KEYEVENTF
Public time As Int32
Public dwExtraInfo As IntPtr
End Structure
<StructLayout(LayoutKind.Sequential, pack:=1)> _
Friend Structure HARDWAREINPUT
Public uMsg As Int32
Public wParamL As Int16
Public wParamH As Int16
End Structure
Friend Enum InputType As Integer
Mouse = 0
Keyboard = 1
Hardware = 2
End Enum
<Flags()> _
Friend Enum KEYEVENTF As Integer
EXTENDEDKEY = 1
KEYUP = 2
[UNICODE] = 4
SCANCODE = 8
End Enum
End Class
* the above code does not work as it's trying to convert key into int16. When you want to send a Control plus some key sequence it generates an exception at that. Control translates to 131072***
Please note that there is an unresolved issue using the SendKeys class in Windows Vista RC1 (Build 5536).
More specifically you may encounter a "Hook cannot be created." exception.
Please also note that there is an unresolved issue using the SendKeys class if ie7 is the target app.
More specifically, extra characters may be added to the input stream.
I was able to send keystrokes (or half keystrokes, i.e. KeyDown - followed sometime later by a KeyUp - for control purposes), sending them one at a time. I was unable to get an array of inputs to be accepted. (The additional keys I was trying to add were Shift, Ctrl, and Alt - so maybe that has some bearing.)
Do you know one? Please contribute it!
I found that using SendKeys to send {TAB} works OK but +{TAB} (i.e. shift-tab) doesn't; IE7 executes a forward-tab in both cases. Using the above routines, the following successfully does a shift-tab in IE7:
helpful tips or sample code to share for using this API in managed code?
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