C++技巧(多媒體定時(shí)器的簡單例子)

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1）新建一個(gè)工程，保存
    2）添加一個(gè)Button和一個(gè)Label
    3）修改unit1.h代碼如下：
    //
    #ifndef Unit1H
    #define Unit1H
    //
    #include
    #include
    #include
    #include
    //
    class TForm1 : public TForm
    {
    __published: // IDEmanaged Components
    TButton *Button1;
    TLabel *Label1;
    void __fastcall Button1Click(TObject *Sender);
    void __fastcall FormCloseQuery(TObject *Sender, bool &CanClose);
    private: // User declarations
    public:　// User declarations
    __fastcall TForm1(TComponent* Owner);
    static void CALLBACK TimeProc(UINT uID,UINT uMsg,
    DWORD dwUser,DWORD dw1,DWORD dw2); // 定時(shí)器回調(diào)函數(shù)
    int TimerID; // 考試大提示: 定時(shí)器ID
    };
    //
    extern PACKAGE TForm1 *Form1;
    //
    #endif
    4)unit1.cpp代碼如下：
    //
    #include
    #include "mmsystem.h"
    #pragma hdrstop
    #include "Unit1.h"
    //
    #pragma package(smart_init)
    #pragma resource "*.dfm"
    TForm1 *Form1;
    //
    __fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
    {
    TimerID = 0;
    }
    //
    void CALLBACK TForm1::TimeProc(UINT uID,UINT uMsg, DWORD dwUser,DWORD dw1,DWORD dw2)
    {
    Form1>Label1>Caption = Now();
    }
    //
    void __fastcall TForm1::Button1Click(TObject *Sender)
    {
    TimerID = timeSetEvent(1000, 0, (LPTIMECALLBACK)TimeProc, 0,
    TIME_PERIODIC|TIME_CALLBACK_FUNCTION); // 設(shè)定多媒體定時(shí)器,1000ms
    if(TimerID == 0)　　{
    ShowMessage("創(chuàng)建失敗");
    }
    }
    //
    void __fastcall TForm1::FormCloseQuery(TObject *Sender, bool &CanClose)
    {
    if(TimerID != 0)　　{
    timeKillEvent(TimerID); // 釋放定時(shí)器
    }
    }
    //
    運(yùn)行效果：點(diǎn)擊按鈕后，Label1開始顯示時(shí)間