睿豐德科技 專注RFID識別技術和條碼識別技術與管理軟件的集成項目。質量追溯系統、MES系統、金蝶與條碼系統對接、用友與條碼系統對接 今天犯了一個粗心的錯誤,在無窗口線程中,SetTimer中設置計時器ID,而WM_TIMER消息響應函數中得到的計時器ID卻不是之前設置的計時器ID.

 

[cpp] view plaincopyprint?

1. // 111902.cpp : Defines the entry point for the console application.   
2. //   
3. //#include "stdafx.h"   
4. #include "stdio.h"   
5. #include "windows.h"   
6. BOOL DispatchThreadMessage(MSG* pMsg);  
7. VOID CALLBACK OnTimerProc(HWND hwnd,UINT uMsg,UINT_PTR idEvent,DWORD dwTime);  
8. int main(int argc, char* argv[])  
9. {  
10.     printf("Hello World!\n");  
11.     ::SetTimer(NULL,45,1000,OnTimerProc);  
12.     MSG msg;  
13.     while (GetMessage(&msg, 0, 0, 0) > 0)  
14.     {  
15.         if (msg.hwnd == NULL && DispatchThreadMessage(&msg))  
16.             continue;  
17.         TranslateMessage(&msg);  
18.         DispatchMessage(&msg);  
19.     }  
20.     return 0;  
21. }  
22.   
23. BOOL DispatchThreadMessage(MSG* pMsg)  
24. {  
25.     if(pMsg->message == 0x0113)  
26.     {  
27.         printf("DispatchThreadMessage: %6d\n",pMsg->wParam);  
28.         return false;         
29.     }  
30.     return false;  
31. }   
32. VOID CALLBACK OnTimerProc(HWND hwnd,UINT uMsg,UINT_PTR idEvent,DWORD dwTime)  
33. {  
34.     printf("OnTimerProc: %6d\n",idEvent);  
35. }  

// 111902.cpp : Defines the entry point for the console application.
//
//#include "stdafx.h"
#include "stdio.h"
#include "windows.h"
BOOL DispatchThreadMessage(MSG* pMsg);
VOID CALLBACK OnTimerProc(HWND hwnd,UINT uMsg,UINT_PTR idEvent,DWORD dwTime);
int main(int argc, char* argv[])
{
	printf("Hello World!\n");
	::SetTimer(NULL,45,1000,OnTimerProc);
	MSG msg;
	while (GetMessage(&msg, 0, 0, 0) > 0)
	{
		if (msg.hwnd == NULL && DispatchThreadMessage(&msg))
			continue;
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return 0;
}

BOOL DispatchThreadMessage(MSG* pMsg)
{
	if(pMsg->message == 0x0113)
	{
		printf("DispatchThreadMessage: %6d\n",pMsg->wParam);
		return false;		
	}
	return false;
} 
VOID CALLBACK OnTimerProc(HWND hwnd,UINT uMsg,UINT_PTR idEvent,DWORD dwTime)
{
	printf("OnTimerProc: %6d\n",idEvent);
}

 

 

對應計時器ID的輸出的是一個隨機數字.

 

原來在msdn中

nIDEvent

[in] Specifies a nonzero timer identifier. If the hWnd parameter is NULL, and the nIDEvent does not match an existing timer then it is ignored and a new timer ID is generated. If the hWnd parameter is not NULL and the window specified by hWnd already has a timer with the value nIDEvent , then the existing timer is replaced by the new timer. When SetTimer replaces a timer, the timer is reset. Therefore, a message will be sent after the current time-out value elapses, but the previously set time-out value is ignored. If the call is not intended to replace an existing timer, nIDEvent should be 0 if the hWnd is NULL.

注:只有當hWnd參數為非空時,計時器的ID為設置的 nIDEvent,  否則系統為你自動生成一個計時器ID,可由返回時值獲取.

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