請問如何Callback？ 可舉簡單的範例嗎? 謝謝

這有一篇: http://www.developers.demon.co.uk/./callback.html    --- 歡迎光臨 KTop 研究院

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brianwung  本篇與 【問題】請問如何寫Callback？http://delphi.ktop.com.tw/topic.php?TOPIC_ID=38722 相同問題請勿重覆發問，因二篇都己答題給分，依時間先後，刪除後篇 另發言前請先閱讀本站版規，以維自身權益    ================轉貼自solnone 會員在後篇的回答===============  

引言: CopyFileEx 可以copy file 要傳入一個callback function, 可回應copy的進度 參考看看 function CopyProgressRoutine( TotalFileSize: LARGE_INTEGER; TotalBytesTransferred: LARGE_INTEGER; StreamSize: LARGE_INTEGER; StreamBytesTransferred: LARGE_INTEGER; dwStreamNumber: DWORD; dwCallbackReason: DWORD; hSourceFile: THandle; hDestinationFile: THandle; lpData: Pointer ): DWORD; stdcall; begin form1.ProgressBar1.Position := Floor((TotalBytesTransferred.QuadPart / TotalFileSize.QuadPart) * 100); Result := PROGRESS_CONTINUE; Application.ProcessMessages; end; procedure TForm1.Button1Click(Sender: TObject); begin CopyFileEx('a.txt', 'b.txt', @CopyProgressRoutine ,nil ,nil , COPY_FILE_RESTARTABLE); end; 另一個sample… type TtestProc = procedure; procedure a; begin ShowMessage('Hello!'); end; procedure b(callBack: TtestProc); begin if Assigned(callback) then callBack; end; procedure TForm1.Button1Click(Sender: TObject); begin b(a); end;