如何在WPF中用C#手动切换NumLock密钥

Question

我已经搜索了一段时间，结果大多是C++或其他语言，而不是C#。我见过的东西：

keybd_event() // A c++ method that theoretically can be included with a DLL import, but hasn't worked in testing
System.Windows.Forms.SendKeys.Send("{NUMLOCK}"}; // Forms namespace doesn't exist in Windows

目前，我有每隔一秒左右执行一次的代码来观察numlock的状态，并相应地更新表单中的图形。如果设置了bool切换，我还希望它强制NumLock打开：

internal partial class Interop
{
public static int VK_NUMLOCK = 0x90;
public static int VK_SCROLL = 0x91;
public static int VK_CAPITAL = 0x14;
public static int KEYEVENTF_EXTENDEDKEY = 0x0001; // If specified, the scan code was preceded by a prefix byte having the value 0xE0 (224).
public static int KEYEVENTF_KEYUP = 0x0002; // If specified, the key is being released. If not specified, the key is being depressed.
[DllImport("User32.dll", SetLastError = true)]
public static extern void keybd_event(
byte bVk,
byte bScan,
int dwFlags,
IntPtr dwExtraInfo);
[DllImport("User32.dll", SetLastError = true)]
public static extern short GetKeyState(int nVirtKey);
[DllImport("User32.dll", SetLastError = true)]
public static extern short GetAsyncKeyState(int vKey);
}
private void watcher(object source, ElapsedEventArgs e) 
{
bool NumLock = (((ushort)GetKeyState(0x90)) & 0xffff) != 0;
if (!NumLock && fixers.watchNumL)
{
// Force NumLock back on
// Simulate a key press
Interop.keybd_event((byte)0x90,0x45,Interop.KEYEVENTF_EXTENDEDKEY | 0,IntPtr.Zero);
// Simulate a key release
Interop.keybd_event((byte)0x90,0x45,Interop.KEYEVENTF_EXTENDEDKEY | Interop.KEYEVENTF_KEYUP,    IntPtr.Zero);
NumLock = (((ushort)GetKeyState(0x90)) & 0xffff) != 0;
}
if (NumLock)
{
this.Dispatcher.Invoke(() =>
{
fixerBoxes["NumL"].FixerImg.Source = new BitmapImage(new Uri(@"/graphics/num_lock_on.png", UriKind.Relative));
StatusBox.Text = "Num Lock ON";
});
}
else {
this.Dispatcher.Invoke(() =>
{
fixerBoxes["NumL"].FixerImg.Source = new BitmapImage(new Uri(@"/graphics/num_lock_off.png", UriKind.Relative));
StatusBox.Text = "Num Lock OFF";
});
}
}

public MainWindow()
{
// Start the watcher
System.Timers.Timer myTimer = new System.Timers.Timer();
// Tell the timer what to do when it elapses
myTimer.Elapsed += new ElapsedEventHandler(watcher);
// Set it to go off every second
myTimer.Interval = 1000;
// And start it        
myTimer.Enabled = true;
}

Answer 1

这里有一个类(带有库(可以为您做到这一点。这个库做得更多，所以仅仅用于这个目的可能有点过头了。该方法使用了使用pinvoke:的keybd_event函数

// Simulate a key press
Interop.keybd_event((byte)virtualKey,
0x45,
Interop.KEYEVENTF_EXTENDEDKEY | 0,
IntPtr.Zero);
// Simulate a key release
Interop.keybd_event((byte)virtualKey,
0x45,
Interop.KEYEVENTF_EXTENDEDKEY | Interop.KEYEVENTF_KEYUP,
IntPtr.Zero);

按下并松开按钮可更改LED的状态。CCD_ 2是VK_。

以下是声明：

internal partial class Interop
{
public static int VK_NUMLOCK = 0x90;
public static int VK_SCROLL = 0x91;
public static int VK_CAPITAL = 0x14;
public static int KEYEVENTF_EXTENDEDKEY = 0x0001; // If specified, the scan code was preceded by a prefix byte having the value 0xE0 (224).
public static int KEYEVENTF_KEYUP = 0x0002; // If specified, the key is being released. If not specified, the key is being depressed.
[DllImport("User32.dll", SetLastError = true)]
public static extern void keybd_event(
byte bVk,
byte bScan,
int dwFlags,
IntPtr dwExtraInfo);
[DllImport("User32.dll", SetLastError = true)]
public static extern short GetKeyState(int nVirtKey);
[DllImport("User32.dll", SetLastError = true)]
public static extern short GetAsyncKeyState(int vKey);
}