Usage of C + + timers: SetTimer and OnTimer

The use of the SetTimer function

1) Use Wm_timer to set the timer

First look at SetTimer, the prototype of this API function.

Uint_ptr SetTimer (HWND hwnd,//and timer associated Windows Uint_ptr nidevent,//a non-0 digital flag This timer UINT uelapse,//Specifies the time interval, in milliseconds Timerproc lptimerfunc//is generally specified as null);

When in the MFC project, the following:

Uint_ptr SetTimer (uint_ptr nidevent,//a non-0 digital flag This timer UINT uelapse,//the specified time interval, in milliseconds Timerproc lptimerfunc//is generally specified as null);

Use the following:

SetTimer (1,1000,null);

Parameters:

1: The name of the timer;

1000: time interval, unit is milliseconds;

NULL: Use the OnTime function.

The WM_TIMER message is triggered at each time to 1s, and its message response function is as follows:

Void cxxx::ontimer (uint_ptr nidevent)  {         //  TODO:  Add the message handler code here and/or call the default value                   //  Add the following code here:                  switch () {                  case 1:                             //doing what should be done                               //call KillTimer (1) Here when it is not needed;                             break;                  default:                            break;                  }      cdialog::ontimer (nidevent);  }

Call KillTimer (nidevent) when no timer is required;

KillTimer (1);

2) What if I want to join two or more than two timer?

Continue with the SetTimer function bar, the last timer ID is 1, this time can be 2,3,4 ....

SetTimer (2,1000,null); SetTimer (3,500,null);

Well, windows will coordinate with them. Of course, the OnTimer function body is also to be changed, to add each timer's processing code in the function body:

OnTimer (nidevent) {switch (nidevent) {Case 1: ...;        Break            Case 2: ...;        Break            Case 3: ...;    Break }}

Usage of C + + timers: SetTimer and OnTimer