问题
This question already has an answer here:
- Capture a keyboard keypress in the background 2 answers
So I have a C# Console Application with a Form, which I want to open using hotkeys. Let's say for example Ctrl + < opens the form. So I got the code to handle a globalkeylistener now, but it looks like I failed by implementing it. It made a while loop to prevent it from closing the program and I tryed to get an input from the user with the kbh_OnKeyPressed method.
I tryed to implement it this way:
using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace Globalkey
{
static class Program
{
[DllImport("user32.dll")]
private static extern bool RegisterHotkey(int id, uint fsModifiers, uint vk);
private static bool lctrlKeyPressed;
private static bool f1KeyPressed;
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
LowLevelKeyboardHook kbh = new LowLevelKeyboardHook();
kbh.OnKeyPressed += kbh_OnKeyPressed;
kbh.OnKeyUnpressed += kbh_OnKeyUnpressed;
kbh.HookKeyboard();
while(true) { }
}
private static void kbh_OnKeyUnpressed(object sender, Keys e)
{
if (e == Keys.LControlKey)
{
lctrlKeyPressed = false;
Console.WriteLine("CTRL unpressed");
}
else if (e == Keys.F1)
{
f1KeyPressed = false;
Console.WriteLine("F1 unpressed");
}
}
private static void kbh_OnKeyPressed(object sender, Keys e)
{
if (e == Keys.LControlKey)
{
lctrlKeyPressed = true;
Console.WriteLine("CTRL pressed");
}
else if (e == Keys.F1)
{
f1KeyPressed = true;
Console.WriteLine("F1 pressed");
}
CheckKeyCombo();
}
static void CheckKeyCombo()
{
if (lctrlKeyPressed && f1KeyPressed)
{
Application.Run(new Form1());
}
}
}
}
回答1:
What you need is a Lowlevel Keyboard Hook.
This could look somewhat like this:
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows.Forms;
public class LowLevelKeyboardHook
{
private const int WH_KEYBOARD_LL = 13;
private const int WM_KEYDOWN = 0x0100;
private const int WM_SYSKEYDOWN = 0x0104;
private const int WM_KEYUP = 0x101;
private const int WM_SYSKEYUP = 0x105;
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool UnhookWindowsHookEx(IntPtr hhk);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr GetModuleHandle(string lpModuleName);
public delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);
public event EventHandler<Keys> OnKeyPressed;
public event EventHandler<Keys> OnKeyUnpressed;
private LowLevelKeyboardProc _proc;
private IntPtr _hookID = IntPtr.Zero;
public LowLevelKeyboardHook()
{
_proc = HookCallback;
}
public void HookKeyboard()
{
_hookID = SetHook(_proc);
}
public void UnHookKeyboard()
{
UnhookWindowsHookEx(_hookID);
}
private IntPtr SetHook(LowLevelKeyboardProc proc)
{
using (Process curProcess = Process.GetCurrentProcess())
using (ProcessModule curModule = curProcess.MainModule)
{
return SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(curModule.ModuleName), 0);
}
}
private IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
{
if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN || wParam == (IntPtr)WM_SYSKEYDOWN)
{
int vkCode = Marshal.ReadInt32(lParam);
OnKeyPressed.Invoke(this, ((Keys)vkCode));
}
else if(nCode >= 0 && wParam == (IntPtr)WM_KEYUP ||wParam == (IntPtr)WM_SYSKEYUP)
{
int vkCode = Marshal.ReadInt32(lParam);
OnKeyUnpressed.Invoke(this, ((Keys)vkCode));
}
return CallNextHookEx(_hookID, nCode, wParam, lParam);
}
}
To implement it, you could use something like this:
kbh = new LowLevelKeyboardHook();
kbh.OnKeyPressed += kbh_OnKeyPressed;
kbh.OnKeyUnpressed += kbh_OnKeyUnpressed;
kbh.HookKeyboard();
The event could be handled like that:
bool lctrlKeyPressed;
bool f1KeyPressed;
void kbh_OnKeyPressed(object sender, Keys e)
{
if (e == Keys.LControlKey)
{
lctrlKeyPressed = true;
}
else if (e == Keys.F1)
{
f1KeyPressed= true;
}
CheckKeyCombo();
}
void kbh_OnKeyUnPressed(object sender, Keys e)
{
if (e == Keys.LControlKey)
{
lctrlKeyPressed = false;
}
else if (e == Keys.F1)
{
f1KeyPressed= false;
}
}
void CheckKeyCombo()
{
if (lctrlKeyPressed && f1KeyPressed)
{
//Open Form
}
}
For actual understanding, i would recommend you to have a read on P/Invoke. That is making use of the unmanaged APIs that windows provides.
For a full list of P/Invoke possibilites, pinvoke.net is a great source.
For better understanding in general, The official MSDN Website is a good source, too.
EDIT:
It seems like you're actually using a Console Application, not a WinForm one. In that case, you have to run the program a bit differently:
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
LowLevelKeyboardHook kbh = new LowLevelKeyboardHook();
kbh.OnKeyPressed += kbh_OnKeyPressed;
kbh.OnKeyUnpressed += kbh_OnKeyUnpressed;
kbh.HookKeyboard();
Application.Run();
kbh.UnHookKeyboard();
}
The Run() method of the Application Class starts a standard loop for your application. This is necessary for the Hook to work, because a mere Console Application without this loop is, as far as I know, not capable of triggering those global key events.
Using this implementation, pressing and releasing the defined keys gives the following output:
Note: I obviously replaced
Application.Run(new Form1());
in the CheckKeyCombo() method with
Console.WriteLine("KeyCombo pressed");
来源：https://stackoverflow.com/questions/46013287/c-sharp-global-keyboard-hook-that-opens-a-form-from-a-console-application