.Net 下全局 HotKey Register & Unregister
.Net 下全局 HotKey Register & Unregister
本文介绍了，在.Net下实现，用系统API注册系统HotKey的全过程。将系统的WM_HOTKEY Message包装成了一个.Net下的Event(用户定义的HotKeyPress Event)。同时简化了系统HotKey的注册过程。
HotKey的注册原理
注册一个HotKey需要下面2个步骤：
1. Import GlobalAddAtom
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[DllImport("kernel32")]
internal static extern IntPtr GlobalAddAtom(string lpString);
GlobalAddAtom是一个系统提供的API，在Kernel32.dll下，这个方法将注册一个字符串到系统的Global Atom Table中，并返回一个唯一的intPtr指示识别这个字符串。
2. Import RegisterHotKey
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[DllImport("user32")]
internal static extern bool RegisterHotKey(IntPtr hWnd,
int id,
uint fsModifiers,
uint vk
);
RegisterHotKey 是一个系统提供的 API，在user32.dll下，这个方法将注册一个HotKey。注册HotKey时需要使用一个AtomID一个系统唯一的标识来注册这个HotKey，当HotKey按下时，系统会发出一个WM_HOTKEY的Message给注册这个HotKey的Application。当这个Application收到消息后作自己想要的操作。
HotKey的使用方法
本文已经包装了HotKey的 WM_HOTKEY 系统 Message 为 HotKeyPressed PrintWindowPressed PrintDesktopPressed 事件(用户定义的事件)，注册 HotKey 时，使用类似 this.HotKeys.Add(new HotKeyController.HotKey("Ctrl+O",Keys.O,HotKey.HotKeyModifiers.MOD_CONTROL)); 来注册这个 HotKey。
需要处理HotKey时使用private void MainForm_HotKeyPressed(object sender, HotKeyController.HotKeyPressedEventArgs e) 来处理 HotKeyEvent。进行自己想做的操作。
部分核心代码
1. 使用到的系统API
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using System;
using System.Runtime.InteropServices;
namespace HotKeyController
{
public class HotKeyUnmanagedMethods
{
public HotKeyUnmanagedMethods()
{
}
~ HotKeyUnmanagedMethods()
{
}
internal static int WM_HOTKEY = 0x312;
[DllImport("user32")]
internal static extern bool RegisterHotKey(IntPtr hWnd,
int id,
uint fsModifiers,
uint vk
);
[DllImport("user32")]
internal static extern bool UnregisterHotKey(IntPtr hWnd,
int id
);
[DllImport("kernel32")]
internal static extern IntPtr GlobalAddAtom(string lpString
);
[DllImport("kernel32")]
internal static extern IntPtr GlobalDeleteAtom(IntPtr nAtom
);
[DllImport("kernel32")]
internal static extern uint GetTickCount();
}
}
2. HotKey类 封装HotKey
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using System;
using System.Windows.Forms;
namespace HotKeyController
{
public class HotKey
{
[Flags()]
public enum HotKeyModifiers
{
MOD_ALT = 0x1,
MOD_CONTROL = 0x2,
MOD_SHIFT = 0x4,
MOD_WIN = 0x8,
}
public HotKey(string name,Keys keyCode,HotKeyModifiers modifiers)
{
this._name = name;
this._keyCode = keyCode;
this._modifiers = modifiers;
}
public HotKey()
{
}
~HotKey()
{
}
//The hot key is or not valiable.
public void Validate()
{
string message = "";
if(this._name.Trim().Length == 0)
{
message = "A hotkey need a name.";
}
if(this._keyCode == Keys.Alt || this._keyCode == Keys.Control ||
this._keyCode == Keys.Shift || this._keyCode == Keys.ShiftKey ||
this._keyCode == Keys.ControlKey)
{
message = "The keycode cannot be set to a modifier key.";
}
if(message.Length > 0)
{
throw new HotKeyException(this,message);
}
}
public string Name
{
get
{
return this._name;
}
set
{
this._name = value;
}
}
public Keys KeyCode
{
get
{
return this._keyCode;
}
set
{
this._keyCode = value;
}
}
public HotKeyModifiers Modifiers
{
get
{
return this._modifiers;
}
set
{
this._modifiers = value;
}
}
private string _name;
private string _atomName;
private IntPtr _atomId;
private Keys _keyCode;
private HotKeyModifiers _modifiers;
//The Atom id will regist to the global system table.
internal IntPtr AtomId
{
get
{
return this._atomId;
}
set
{
this._atomId = value;
}
}
//The global atom name.
internal string AtomName
{
get
{
return this._atomName;
}
set
{
this._atomName = value;
}
}
}
}
3. HotKey Collection HotKey 的集合 存储管理 所有注册的HotKey
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using System;
namespace HotKeyController
{
public class HotKeyCollection:System.Collections.CollectionBase
{
//the hot key collections owner form.
public HotKeyCollection(System.Windows.Forms.Form ownerForm)
{
this._ownerForm = ownerForm;
}
//Get a hot key.
public HotKey this[int index]
{
get
{
return (HotKey)this.InnerList[index];
}
}
//Add a hot key.
public void Add(HotKey hotKey)
{
hotKey.Validate();
this.AddHotKey(hotKey);
this.InnerList.Add(hotKey);
}
//Remove a hot key.
public void Remove(HotKey hotKey)
{
hotKey.Validate();
this.RemoveHotKey(hotKey);
this.InnerList.Remove(hotKey);
}
public void Remove(int index)
{
if(index>=this.InnerList.Count)
{
return;
}
else
{
this.RemoveHotKey((HotKey)this.InnerList[index]);
this.InnerList.RemoveAt(index);
}
}
public void RemoveAll()
{
while(this.InnerList.Count>0)
{
this.RemoveHotKey((HotKey)this.InnerList[0]);
this.InnerList.RemoveAt(0);
}
}
private System.Windows.Forms.Form _ownerForm;
//Real add a hot key to system, use unmanagement methods.
private void AddHotKey(HotKey hotKey)
{
string atomName;
IntPtr atomId;
bool registered;
//get a atom name
atomName = hotKey.Name + "_" + HotKeyUnmanagedMethods.GetTickCount().ToString();
if(atomName.Length > 255)
{
atomName = atomName.Substring(0,255);
}
atomId = HotKeyUnmanagedMethods.GlobalAddAtom(atomName);
//get a tom id
if(atomId.Equals(IntPtr.Zero))
{
throw new HotKeyException(hotKey,"Failed to add a global atom for this HotKey");
}
else
{
//regist a hot key.
registered = HotKeyUnmanagedMethods.RegisterHotKey(this._ownerForm.Handle,atomId.ToInt32(),System.Convert.ToUInt32(hotKey.Modifiers), System.Convert.ToUInt32(hotKey.KeyCode));
if(!registered)
{
//unsuccessful.
HotKeyUnmanagedMethods.GlobalDeleteAtom(atomId);
throw new HotKeyException(hotKey,"Failed to register this HotKey");
}
else
{
//successful.
hotKey.AtomName = atomName;
hotKey.AtomId = atomId;
}
}
}
//Real remove a hot key, use unmanagement methods.
private void RemoveHotKey(HotKey hotKey)
{
// remove the hot key:
HotKeyUnmanagedMethods.UnregisterHotKey(this._ownerForm.Handle, hotKey.AtomId.ToInt32());
// unregister the atom:
HotKeyUnmanagedMethods.GlobalDeleteAtom(hotKey.AtomId);
}
//Clean all hot keys.
protected override void OnClear()
{
foreach(HotKey hotKey in this.InnerList)
{
this.RemoveHotKey(hotKey);
}
base.OnClear ();
}
protected override void OnInsert(int index, object value)
{
if(value.GetType().IsInstanceOfType(new HotKey()))
{
((HotKey)value).Validate();
this.AddHotKey((HotKey)value);
base.OnInsert (index, value);
}
else
{
throw new InvalidCastException("The want to insert object is no a hotkey");
}
}
protected override void OnRemove(int index, object value)
{
if(value.GetType().IsInstanceOfType(new HotKey()))
{
this.RemoveHotKey((HotKey)value);
base.OnRemove(index, value);
}
else
{
throw new InvalidCastException("The want to remove object is no a hotkey");
}
}
protected override void OnSet(int index, object oldValue, object newValue)
{
HotKey hotKey;
hotKey = new HotKey();
if(oldValue.GetType().IsInstanceOfType(hotKey)&&newValue.GetType().IsInstanceOfType(newValue))
{
base.OnSet (index, ((HotKey)oldValue), ((HotKey)newValue));
}
else
{
throw new InvalidCastException("The want to set object is no a hotkey");
}
}
protected override void OnValidate(object value)
{
((HotKey)value).Validate();
}
}
}
其中的 Private AddHotKey RemoveHotKey 调用了 系统的API 真正的注册一个HotKey 注销 一个HotKey。
4. HotKey Controller 重写窗体的WndProc方法 接收WM_HOTKEY Message 同时触发 HotKey Event 供Controller 的父类接收处理
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using System;
namespace HotKeyController
{
public delegate void HotKeyPressedEventHandler(object sender, HotKeyPressedEventArgs e);
public class HotKeyController : System.Windows.Forms.Form
{
public HotKeyController()
{
this._hotKeys = new HotKeyCollection(this);
}
~HotKeyController()
{
this._hotKeys.Clear();
}
public event HotKeyPressedEventHandler HotKeyPressed;
public HotKeyCollection HotKeys
{
get
{
return this._hotKeys;
}
}
private HotKeyCollection _hotKeys;
protected override void WndProc(ref System.Windows.Forms.Message m)
{
base.WndProc (ref m);
if (m.Msg == HotKeyUnmanagedMethods.WM_HOTKEY)
{
foreach (HotKey hotKey in this._hotKeys)
{
if (hotKey.AtomId.Equals(m.WParam))
{
HotKeyPressedEventArgs hotKeyArgs = new HotKeyPressedEventArgs(hotKey);
if (this.HotKeyPressed != null)
{
this.HotKeyPressed(this, hotKeyArgs);
}
}
}
}
}
}
}
5. HotKeyController 父类窗体对HotKey的处理 添加事件处理方法
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this.HotKeyPressed +=new HotKeyPressedEventHandler(MainForm_HotKeyPressed);
//从HotKeyPressedEventArgs中得到Press的HotKey
private void MainForm_HotKeyPressed(object sender, HotKeyController.HotKeyPressedEventArgs e)
{
if(e.PressedHotKey!= null)
{
MessageBox.Show("Hot key "+e.PressedHotKey.Name +" Pressed","A hot key pressed",MessageBoxButtons.OK,MessageBoxIcon.Information);
}
}
This post is licensed under CC BY 4.0 by the author.