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vkkeyscan (user32)
 
.
Summary
The VkKeyScan function translates a character to the corresponding virtual-key code and shift state for the current keyboard

C# Signature:

[DllImport("user32.dll", CharSet = CharSet.Unicode)]
static extern short VkKeyScan(char ch);

User-Defined Types:

    [StructLayout( LayoutKind.Explicit )]
    public struct INPUT
    {
    [FieldOffset( 0 )]
    public int type;
    [FieldOffset( 4 )]
    public KEYBDINPUT ki;
    }

    [StructLayout( LayoutKind.Sequential )]
    public struct KEYBDINPUT
    {
    public ushort wVk;
    public ushort wScan;
    public uint dwFlags;
    public uint time;
    public IntPtr dwExtraInfo;
    }

Notes:

The CharSet.Unicode is needed on the DllImport declaration for the marshaler to correctly marshal unicode chars

Tips & Tricks:

Please add some!

The VkKeyScanEx function allows to specify a locale.

This function allows you to map the contents of a string or a Textbox into keystrokes, as shown in the sample code

Sample Code:

Warning

This sample code shows how to read the text from a string and send it as keystrokes to Windows. It uses the SetForegroundWindow, SendInput, VkKeyScan functions.

    void Main () {
    string text = "abc123";                // text we will send
    Process notepad = Process.Start( "notepad" );    // launch notepad, we'll write into it
    Thread.Sleep( 2000 );                //give notepad some time to launch
    SetForegroundWindow( notepad.MainWindowHandle );// bring that notepad to the foreground
    short key = 0;        //variable where we will hold the value of each key

    // create an INPUT structure with default values
    INPUT input = new INPUT();
    input.type = INPUT_KEYBOARD;
    input.ki = new KEYBDINPUT();
    input.ki.dwExtraInfo = GetMessageExtraInfo();
    input.ki.dwFlags = 0;
    input.ki.time = 0;
    input.ki.wScan = 0;


    foreach ( char c in text ) {
        key = VkKeyScan( c );       //get the key for this character
        input.ki.wVk = (ushort) key;//update the input structure
        SendInput( 1, ref input, Marshal.SizeOf( input ) );//send the key to notepad
    }
    }

    [DllImport( "user32.dll" )]
    public static extern bool SetForegroundWindow (IntPtr hWnd);

    [DllImport( "user32.dll", SetLastError = true )]
    public static extern uint SendInput (uint nInputs, ref INPUT pInputs, int cbSize);
    public const int INPUT_KEYBOARD = 1;

    [DllImport( "user32.dll" )]
    public static extern IntPtr GetMessageExtraInfo ();

Alternative Managed API:

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Documentation
VkKeyScan on MSDN

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