【IT168 技术文档】在C#中目前我还没有找到发送消息的类成员函数，所以只能采用通过调用WIN 32 API 的 SendMessage() 函数实现。由于 SendMessage的参数中需要得到窗体的句柄(handler) ，所以又要调用另一个API FindWindow(), 两者配合使用，达到在不同窗体之间的消息发送和接收功能。
另外一个要点是，需要通过重写(Override) 窗体的 DefWndProc() 过程来接收自定义的消息。DefWndProc 的重写：
protected override void DefWndProc(ref System.Windows.Forms.Message m)
{
switch(m.Msg)
{
case ...:
break;
default:
base.DefWndProc(ref m);
break;
}
}
{
switch(m.Msg)
{
case ...:
break;
default:
base.DefWndProc(ref m);
break;
}
}
下面是我的C#实践例程。
/////////////////////////////////////////
///file name: Note.cs
///
public class Note
{
//声明 API 函数
[DllImport("User32.dll",EntryPoint="SendMessage")]
private static extern int SendMessage(
int hWnd, // handle to destination window
int Msg, // message
int wParam, // first message parameter
int lParam // second message parameter
);
[DllImport("User32.dll",EntryPoint="FindWindow")]
private static extern int FindWindow(string lpClassName,string
lpWindowName);
//定义消息常数
public const int USER = 0x500;
public const int TEST = USER + 1;
//向窗体发送消息的函数
private void SendMsgToMainForm(int MSG)
{
int WINDOW_HANDLER = FindWindow(null,@"Note Pad");
if(WINDOW_HANDLER == 0)
{
throw new Exception("Could not find Main window!");
}
SendMessage(WINDOW_HANDLER,MSG,100,200);
}
}
/////////////////////////////////////////
/// File name : Form1.cs
/// 接收消息的窗体
///
public class Form1 : System.Windows.Forms.Form
{
public Form1()
{
//
// Required for Windows Form Designer support
//
InitializeComponent();
//
// TODO: Add any constructor code after InitializeComponent call
//
}
/// 重写窗体的消息处理函数
protected override void DefWndProc(ref System.Windows.Forms.Message m)
{
switch(m.Msg)
{
//接收自定义消息 USER，并显示其参数
case Note.USER:
string message = string.Format ("Received message!
parameters are :{0},{1}",m.WParam ,m.LParam);
MessageBox.Show (message);
break;
default:
base.DefWndProc(ref m);
break;
}
//Console.WriteLine(m.LParam);
}
///file name: Note.cs
///
public class Note
{
//声明 API 函数
[DllImport("User32.dll",EntryPoint="SendMessage")]
private static extern int SendMessage(
int hWnd, // handle to destination window
int Msg, // message
int wParam, // first message parameter
int lParam // second message parameter
);
[DllImport("User32.dll",EntryPoint="FindWindow")]
private static extern int FindWindow(string lpClassName,string
lpWindowName);
//定义消息常数
public const int USER = 0x500;
public const int TEST = USER + 1;
//向窗体发送消息的函数
private void SendMsgToMainForm(int MSG)
{
int WINDOW_HANDLER = FindWindow(null,@"Note Pad");
if(WINDOW_HANDLER == 0)
{
throw new Exception("Could not find Main window!");
}
SendMessage(WINDOW_HANDLER,MSG,100,200);
}
}
/////////////////////////////////////////
/// File name : Form1.cs
/// 接收消息的窗体
///
public class Form1 : System.Windows.Forms.Form
{
public Form1()
{
//
// Required for Windows Form Designer support
//
InitializeComponent();
//
// TODO: Add any constructor code after InitializeComponent call
//
}
/// 重写窗体的消息处理函数
protected override void DefWndProc(ref System.Windows.Forms.Message m)
{
switch(m.Msg)
{
//接收自定义消息 USER，并显示其参数
case Note.USER:
string message = string.Format ("Received message!
parameters are :{0},{1}",m.WParam ,m.LParam);
MessageBox.Show (message);
break;
default:
base.DefWndProc(ref m);
break;
}
//Console.WriteLine(m.LParam);
}
