# getkeyboardstate

### C# Signature:

```cs
[DllImport("user32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool GetKeyboardState(byte [] lpKeyState);
```

### VB Signature:

```cs
<DllImport("user32.dll", SetLastError := true)> _
    Private Shared Function GetKeyboardState(ByVal keyState() As Byte) As Boolean
    End Function

'or...
Private Declare Function GetKeyboardState Lib "user32" (ByVal keyState() As Byte) As Boolean
```

### C#:

```cs
using System;
    using System.Runtime.InteropServices;
    using System.ComponentModel;

    namespace PInvokeSample {
        public static class Keyboard {

         public static int GetKeyState(){
            byte[] keys = new byte[256];

            //Get pressed keys
            if(!NativeMethods.GetKeyboardState(keys)){
                int err = Marshal.GetLastWin32Error();
                throw new Win32Exception(err);
            }

            for(int i = 0; i < 256; i++){

             byte key = keys[i];

             //Logical 'and' so we can drop the low-order bit for toggled keys, else that key will appear with the value 1!
             if((key & 0x80) != 0){

            //This is just for a short demo, you may want this to return
            //multiple keys!
                return (int)key;
             }
            }
            return -1;
          }
          }
    }
```

### C#:

```cs
using System;
    using System.Runtime.InteropServices;

    namespace PInvokeSample {
    internal static class NativeMethods {

        [DllImport("User32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool GetKeyboardState(byte[] lpKeyState);

     }
     }
```

### VB:

```cs
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Me.Text = "Caps:" & NativeMethods.CapsLockState.ToString
    Me.Text &= ", Num: " & NativeMethods.NumLockState.ToString
    Me.Text &= ", Scroll: " & NativeMethods.ScrollLockState.ToString
    End Sub
```

### VB:

```cs
Private Shared keyState() As Byte

    <DllImport("user32.dll")> _
    Private Shared Function GetKeyboardState(ByVal keyState() As Byte) As Boolean
    End Function

    Private Shared Sub Update()
    keyState = New Byte(256) {}
    Dim result As Boolean = GetKeyboardState(keyState)
    ' Check for error:
    If result = False Then
        Debug.WriteLine("GetKeyBoardState error: " & Marshal.GetLastWin32Error)
        Throw New Exception("GetKeyBoardState error: " & Marshal.GetLastWin32Error)
    End If
    End Sub

    Public Enum LightState
    Off
    [On]
    End Enum

    ' Example - the keyboard lights...

    Public Shared ReadOnly Property CapsLockState() As LightState
    Get
        Update()
        Dim isOn As Boolean = (keyState(Keys.CapsLock) = 1)
        Return IIf(isOn, LightState.On, LightState.Off)
    End Get
    End Property

    Public Shared ReadOnly Property NumLockState() As LightState
    Get
        Update()
        Dim isOn As Boolean = (keyState(Keys.NumLock) = 1)
        Return IIf(isOn, LightState.On, LightState.Off)
    End Get
    End Property

    Public Shared ReadOnly Property ScrollLockState() As LightState
    Get
        Update()
        Dim isOn As Boolean = (keyState(Keys.Scroll) = 1)
        Return IIf(isOn, LightState.On, LightState.Off)
    End Get
    End Property
```

### Alternative Managed API:

```cs
using System;
    using System.Collections.Generic;
    using System.Runtime.InteropServices;
    using System.Text;

    namespace PInvoke.Net
    {
        public class Keyboard
        {
            [DllImport( "user32.dll" )]
            static extern short GetKeyState( VirtualKeyStates nVirtKey );

            public static bool IsKeyPressed( VirtualKeyStates testKey )
            {
                bool keyPressed = false;
                short result = GetKeyState( testKey );

                switch( result )
                {
                    case 0:
                    // Not pressed and not toggled on.
                    keyPressed = false;
                    break;

                    case 1:
                    // Not pressed, but toggled on
                    keyPressed = false;
                    break;

                    default:
                    // Pressed (and may be toggled on)
                    keyPressed = true;
                    break;
                }

                return keyPressed;
            }

            public enum VirtualKeyStates : int
            {
                VK_LBUTTON = 0x01,
                VK_RBUTTON = 0x02,
                VK_CANCEL = 0x03,
                VK_MBUTTON = 0x04,
                //
                VK_XBUTTON1 = 0x05,
                VK_XBUTTON2 = 0x06,
                //
                VK_BACK = 0x08,
                VK_TAB = 0x09,
                //
                VK_CLEAR = 0x0C,
                VK_RETURN = 0x0D,
                //
                VK_SHIFT = 0x10,
                VK_CONTROL = 0x11,
                VK_MENU = 0x12,
                VK_PAUSE = 0x13,
                VK_CAPITAL = 0x14,
                //
                VK_KANA = 0x15,
                VK_HANGEUL = 0x15, /* old name - should be here for compatibility */
                VK_HANGUL = 0x15,
                VK_JUNJA = 0x17,
                VK_FINAL = 0x18,
                VK_HANJA = 0x19,
                VK_KANJI = 0x19,
                //
                VK_ESCAPE = 0x1B,
                //
                VK_CONVERT = 0x1C,
                VK_NONCONVERT = 0x1D,
                VK_ACCEPT = 0x1E,
                VK_MODECHANGE = 0x1F,
                //
                VK_SPACE = 0x20,
                VK_PRIOR = 0x21,
                VK_NEXT = 0x22,
                VK_END = 0x23,
                VK_HOME = 0x24,
                VK_LEFT = 0x25,
                VK_UP = 0x26,
                VK_RIGHT = 0x27,
                VK_DOWN = 0x28,
                VK_SELECT = 0x29,
                VK_PRINT = 0x2A,
                VK_EXECUTE = 0x2B,
                VK_SNAPSHOT = 0x2C,
                VK_INSERT = 0x2D,
                VK_DELETE = 0x2E,
                VK_HELP = 0x2F,
                //
                VK_LWIN = 0x5B,
                VK_RWIN = 0x5C,
                VK_APPS = 0x5D,
                //
                VK_SLEEP = 0x5F,
                //
                VK_NUMPAD0 = 0x60,
                VK_NUMPAD1 = 0x61,
                VK_NUMPAD2 = 0x62,
                VK_NUMPAD3 = 0x63,
                VK_NUMPAD4 = 0x64,
                VK_NUMPAD5 = 0x65,
                VK_NUMPAD6 = 0x66,
                VK_NUMPAD7 = 0x67,
                VK_NUMPAD8 = 0x68,
                VK_NUMPAD9 = 0x69,
                VK_MULTIPLY = 0x6A,
                VK_ADD = 0x6B,
                VK_SEPARATOR = 0x6C,
                VK_SUBTRACT = 0x6D,
                VK_DECIMAL = 0x6E,
                VK_DIVIDE = 0x6F,
                VK_F1 = 0x70,
                VK_F2 = 0x71,
                VK_F3 = 0x72,
                VK_F4 = 0x73,
                VK_F5 = 0x74,
                VK_F6 = 0x75,
                VK_F7 = 0x76,
                VK_F8 = 0x77,
                VK_F9 = 0x78,
                VK_F10 = 0x79,
                VK_F11 = 0x7A,
                VK_F12 = 0x7B,
                VK_F13 = 0x7C,
                VK_F14 = 0x7D,
                VK_F15 = 0x7E,
                VK_F16 = 0x7F,
                VK_F17 = 0x80,
                VK_F18 = 0x81,
                VK_F19 = 0x82,
                VK_F20 = 0x83,
                VK_F21 = 0x84,
                VK_F22 = 0x85,
                VK_F23 = 0x86,
                VK_F24 = 0x87,
                //
                VK_NUMLOCK = 0x90,
                VK_SCROLL = 0x91,
                //
                VK_OEM_NEC_EQUAL = 0x92, // '=' key on numpad
                //
                VK_OEM_FJ_JISHO = 0x92, // 'Dictionary' key
                VK_OEM_FJ_MASSHOU = 0x93, // 'Unregister word' key
                VK_OEM_FJ_TOUROKU = 0x94, // 'Register word' key
                VK_OEM_FJ_LOYA = 0x95, // 'Left OYAYUBI' key
                VK_OEM_FJ_ROYA = 0x96, // 'Right OYAYUBI' key
                //
                VK_LSHIFT = 0xA0,
                VK_RSHIFT = 0xA1,
                VK_LCONTROL = 0xA2,
                VK_RCONTROL = 0xA3,
                VK_LMENU = 0xA4,
                VK_RMENU = 0xA5,
                //
                VK_BROWSER_BACK = 0xA6,
                VK_BROWSER_FORWARD = 0xA7,
                VK_BROWSER_REFRESH = 0xA8,
                VK_BROWSER_STOP = 0xA9,
                VK_BROWSER_SEARCH = 0xAA,
                VK_BROWSER_FAVORITES = 0xAB,
                VK_BROWSER_HOME = 0xAC,
                //
                VK_VOLUME_MUTE = 0xAD,
                VK_VOLUME_DOWN = 0xAE,
                VK_VOLUME_UP = 0xAF,
                VK_MEDIA_NEXT_TRACK = 0xB0,
                VK_MEDIA_PREV_TRACK = 0xB1,
                VK_MEDIA_STOP = 0xB2,
                VK_MEDIA_PLAY_PAUSE = 0xB3,
                VK_LAUNCH_MAIL = 0xB4,
                VK_LAUNCH_MEDIA_SELECT = 0xB5,
                VK_LAUNCH_APP1 = 0xB6,
                VK_LAUNCH_APP2 = 0xB7,
                //
                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
                //
                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,
                //
                VK_OEM_AX = 0xE1, // 'AX' key on Japanese AX kbd
                VK_OEM_102 = 0xE2, // "<>" or "\|" on RT 102-key kbd.
                VK_ICO_HELP = 0xE3, // Help key on ICO
                VK_ICO_00 = 0xE4, // 00 key on ICO
                //
                VK_PROCESSKEY = 0xE5,
                //
                VK_ICO_CLEAR = 0xE6,
                //
                VK_PACKET = 0xE7,
                //
                VK_OEM_RESET = 0xE9,
                VK_OEM_JUMP = 0xEA,
                VK_OEM_PA1 = 0xEB,
                VK_OEM_PA2 = 0xEC,
                VK_OEM_PA3 = 0xED,
                VK_OEM_WSCTRL = 0xEE,
                VK_OEM_CUSEL = 0xEF,
                VK_OEM_ATTN = 0xF0,
                VK_OEM_FINISH = 0xF1,
                VK_OEM_COPY = 0xF2,
                VK_OEM_AUTO = 0xF3,
                VK_OEM_ENLW = 0xF4,
                VK_OEM_BACKTAB = 0xF5,
                //
                VK_ATTN = 0xF6,
                VK_CRSEL = 0xF7,
                VK_EXSEL = 0xF8,
                VK_EREOF = 0xF9,
                VK_PLAY = 0xFA,
                VK_ZOOM = 0xFB,
                VK_NONAME = 0xFC,
                VK_PA1 = 0xFD,
                VK_OEM_CLEAR = 0xFE
            }
        }
    }
```
