问题
I am currently working on an application which requires different behaviour based on whether the user presses the right or left shift key (RShiftKey, LShiftKey), however when either of these keys is pressed I only see ShiftKey | Shift.
Is there something wrong with my keyboard? (laptop) do I need a new keyboard driver/keyboard in order to send the different key commands maybe...
This is a pretty massive problem at the moment, as there is no way of testing that the code works (apart from unit tests). Anyone had any experience of the different shift/alt/ctrl keys?
回答1:
I don't know if this post will help you or not, but it looks like you may have to mess with InteropServices and Diagnostics:
MSDN Forum: How to send Left/Right shift key
Edit: I finally figured out how to make GetAsyncKeyState() work, as adrianbanks revealed.
[System.Runtime.InteropServices.DllImport("user32.dll")]
private static extern short GetAsyncKeyState(Keys vKey);
private void theForm_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.ShiftKey)
{
if (Convert.ToBoolean(GetAsyncKeyState(Keys.LShiftKey)))
{
Console.WriteLine("Left");
}
if (Convert.ToBoolean(GetAsyncKeyState(Keys.RShiftKey)))
{
Console.WriteLine("Right");
}
}
}
回答2:
Take a look at the GetAsyncKeyState Win32 method. You can add a pInvoke call to it using:
[DllImport("user32.dll")]
private static extern short GetAsyncKeyState(Keys key);
and then handle the KeyDown event on your form:
private void MyForm_KeyDown(object sender, KeyEventArgs e)
{
Console.WriteLine("Left Shift : " + (GetAsyncKeyState(Keys.LShiftKey) < 0));
Console.WriteLine("Right Shift: " + (GetAsyncKeyState(Keys.RShiftKey) < 0));
}
回答3:
Thanks guys, good solution there. In the mean time here's my own "hacky" way of doing it from the override of ProcessCmdKey:
public override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
if (msg.LParam.ToInt32() == 0x2a0001)
LastShiftKey = ShiftKeys.NumericShift;
else if (msg.LParam.ToInt32() == 0x360001)
LastShiftKey = ShiftKeys.AlphaShift;
etc....
}
回答4:
I had a similar need to differentiate between the left and right shift and control keys. Here's my rather-longer but possibly better solution. If you want to catch the alt keys, you'll need to override some other things to prevent them from activating any menu(s). ((int)m.LParam & 0xFFFF) should give the repeat count, but it never seems to go above 2.
protected override bool ProcessKeyMessage(ref Message m)
{
if ((m.Msg == WM_KEYDOWN || m.Msg == WM_KEYUP) && ((int)m.WParam == VK_CONTROL || (int)m.WParam == VK_SHIFT))
{
KeyEventArgs e = new KeyEventArgs(Keys.None);
switch ((OemScanCode)(((int)m.LParam >> 16) & 0x1FF))
{
case OemScanCode.LControl:
e = new KeyEventArgs(Keys.LControlKey);
break;
case OemScanCode.RControl:
e = new KeyEventArgs(Keys.RControlKey);
break;
case OemScanCode.LShift:
e = new KeyEventArgs(Keys.LShiftKey);
break;
case OemScanCode.RShift:
e = new KeyEventArgs(Keys.RShiftKey);
break;
default:
if ((int)m.WParam == VK_SHIFT)
e = new KeyEventArgs(Keys.ShiftKey);
else if ((int)m.WParam == VK_CONTROL)
e = new KeyEventArgs(Keys.ControlKey);
break;
}
if (e.KeyData != Keys.None)
{
if (m.Msg == WM_KEYDOWN)
OnKeyDown(e);
else
OnKeyUp(e);
return true;
}
}
return base.ProcessKeyMessage(ref m);
}
#region Scan code & window message stuff
const int WM_KEYDOWN = 0x100;
const int WM_KEYUP = 0x101;
const int VK_SHIFT = 0x10;
const int VK_CONTROL = 0x11;
/// <summary>
/// Alt key
/// </summary>
const int VK_MENU = 0x12;
/// <summary>
/// List of scan codes for standard 104-key keyboard US English keyboard
/// </summary>
enum OemScanCode
{
/// <summary>
/// ` ~
/// </summary>
BacktickTilde = 0x29,
/// <summary>
/// 1 !
/// </summary>
N1 = 2,
/// <summary>
/// 2 @
/// </summary>
N2 = 3,
/// <summary>
/// 3 #
/// </summary>
N3 = 4,
/// <summary>
/// 4 $
/// </summary>
N4 = 5,
/// <summary>
/// 5 %
/// </summary>
N5 = 6,
/// <summary>
/// 6 ^
/// </summary>
N6 = 7,
/// <summary>
/// 7 &
/// </summary>
N7 = 8,
/// <summary>
/// 8 *
/// </summary>
N8 = 9,
/// <summary>
/// 9 (
/// </summary>
N9 = 0x0A,
/// <summary>
/// 0 )
/// </summary>
N0 = 0x0B,
/// <summary>
/// - _
/// </summary>
MinusDash = 0x0C,
/// <summary>
/// = +
/// </summary>
Equals = 0x0D,
Backspace = 0x0E,
Tab = 0x0F,
Q = 0x10,
W = 0x11,
E = 0x12,
R = 0x13,
T = 0x14,
Y = 0x15,
U = 0x16,
I = 0x17,
O = 0x18,
P = 0x19,
/// <summary>
/// [ {
/// </summary>
LBracket = 0x1A,
/// <summary>
/// ] }
/// </summary>
RBracket = 0x1B,
/// <summary>
/// | \ (same as pipe)
/// </summary>
VerticalBar = 0x2B,
/// <summary>
/// | \ (same as vertical bar)
/// </summary>
Pipe = 0x2B,
CapsLock = 0x3A,
A = 0x1E,
S = 0x1F,
D = 0x20,
F = 0x21,
G = 0x22,
H = 0x23,
J = 0x24,
K = 0x25,
L = 0x26,
/// <summary>
/// ; :
/// </summary>
SemiColon = 0x27,
/// <summary>
/// ' "
/// </summary>
Quotes = 0x28,
// Unused
Enter = 0x1C,
LShift = 0x2A,
Z = 0x2C,
X = 0x2D,
C = 0x2E,
V = 0x2F,
B = 0x30,
N = 0x31,
M = 0x32,
/// <summary>
/// , <
/// </summary>
Comma = 0x33,
/// <summary>
/// . >
/// </summary>
Period = 0x34,
/// <summary>
/// / ?
/// </summary>
Slash = 0x35,
RShift = 0x36,
LControl = 0x1D,
LAlternate = 0x38,
SpaceBar = 0x39,
RAlternate = 0x138,
RControl = 0x11D,
/// <summary>
/// The menu key thingy
/// </summary>
Application = 0x15D,
Insert = 0x152,
Delete = 0x153,
Home = 0x147,
End = 0x14F,
PageUp = 0x149,
PageDown = 0x151,
UpArrow = 0x148,
DownArrow = 0x150,
LeftArrow = 0x14B,
RightArrow = 0x14D,
NumLock = 0x145,
NumPad0 = 0x52,
NumPad1 = 0x4F,
NumPad2 = 0x50,
NumPad3 = 0x51,
NumPad4 = 0x4B,
NumPad5 = 0x4C,
NumPad6 = 0x4D,
NumPad7 = 0x47,
NumPad8 = 0x48,
NumPad9 = 0x49,
NumPadDecimal = 0x53,
NumPadEnter = 0x11C,
NumPadPlus = 0x4E,
NumPadMinus = 0x4A,
NumPadAsterisk = 0x37,
NumPadSlash = 0x135,
Escape = 1,
PrintScreen = 0x137,
ScrollLock = 0x46,
PauseBreak = 0x45,
LeftWindows = 0x15B,
RightWindows = 0x15C,
F1 = 0x3B,
F2 = 0x3C,
F3 = 0x3D,
F4 = 0x3E,
F5 = 0x3F,
F6 = 0x40,
F7 = 0x41,
F8 = 0x42,
F9 = 0x43,
F10 = 0x44,
F11 = 0x57,
F12 = 0x58,
}
#endregion
来源：https://stackoverflow.com/questions/2569268/net-difference-between-right-shift-and-left-shift-keys