In C #, the driver adopted by the program uses event drivers instead of the original message driver, although the .NET framework provides the events provided by the .NET framework, it is very rich in the previous system. Implementation method, so use messages in C # sometimes greatly improved programming efficiency.
1 define a message
Messages in C # need to be defined as the original 16 credit number in the Windows system, such as
Const int WM_LBUTTON = 0x201; // Defines the left button of the mouse click message
Public const int user = 0x0400 // is a user message defined by the Windows system
2 messages
Message Send is defined by the API function sendMessage provided by Windows.
[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;
3 messages
In C #, all windows have also messages reception processing functions, that is, DEFPROC functions
You can overload this function in the Form to process messages
Protected Override Void DefWndProc (Ref System.winForms.Message M)
{
Switch (m.msg)
{
Case WM_LButton:
/// String is different from the method of usage of cstring in the MFC.
String message = string.format ("Received Message! Parameters: {0}, {1}", M.WParam, M.LParam;
MessageBox.show (Message); // / Display a message box
Break;
DEFAULT:
Base.defwndproc (REF M); // Call the base class function to handle non-custom messages.
Break;
}
}
In fact, the events in the C # are also implemented by packaging system messages. If you do not process it in the DEFWndProc function
Then, he will give the system to process the message, the system will pass the agent to implement the processing function of the mouse click, so you can pass
DEFPROC function to block messages, such as you want to intercept a button click message
4 other messaging methods in C #
In C #, you need to preprocess the message's message, such as you use the OWC's Spreedsheet control to process the Excel file, you don't want users to choose casually
The data is edited, you can block the mouse event, this time you must intercept the system's pre-defined event (this is called subcatenification in the MFC), you can provide one of the interfaces provided via C #
IMessageFilter to implement the filter filter
Public Class Form1: System.Windows.Forms.form, iMessageFilter
{
Const int WM_MOUSEMOVE = 0x200
Public Bool PrefilterMessage (Ref Message M) {Keys Keycode = (int) m.wparam & keys.keycode; if (m.msg == m.msg == wm_mousemove) //||m.msg == wm_lbuttondown {//Messagebox.show("ignoring escape ... "); return true;}}}}}
