Delphi Base Class - TProc (CHT)

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TProc 在 Delphi 的宣告是：

1 2 3 4 5

TProc = reference to procedure; TProc<T> = reference to procedure (Arg1: T); TProc<T1,T2> = reference to procedure (Arg1: T1; Arg2: T2); TProc<T1,T2,T3> = reference to procedure (Arg1: T1; Arg2: T2; Arg3: T3); TProc<T1,T2,T3,T4> = reference to procedure (Arg1: T1; Arg2: T2; Arg3: T3; Arg4: T4);

最近在寫測速程式時突然應用到它，我是這麼寫的：

function RunLongTime(AProc: TProc): Int64;
 var
  sw : TStopWatch;
begin
  sw := TStopWatch.Create() ;
  try
    sw.Start;
    AProc;
    sw.Stop;
    Result := sw.ElapsedMilliseconds;
  finally
  end;
end;

如此一來，任何想知道要執行時間的程式全都可以丟到這裡來，像是：

procedure ExportXLSX;
var
  LPos01: Integer;
  LGUID: TGUID;
begin
  // Open Excel OLE
  ExcelFile :=  CreateOleObject('Excel.Application');
  ExcelFile.DisplayAlerts := False;
  // Handle WoorkBook
  if not VarIsNull(ExcelFile) then begin
    WorkBook := ExcelFile.WorkBooks.Add;
      if not VarIsNull(WorkBook) then begin
      // Handle Sheet
          WorkSheet := WorkBook.WorkSheets[1];
      end;
    for LPos01 := 1 to StrToInt(Edit1.Text) do
    begin
      WorkSheet.Cells(LPos01, 1) := LPos01;
      LGUID := TGUID.NewGuid;
      WorkSheet.Cells(LPos01, 2) := LGUID.ToString;
    end;
    WorkSheet.SaveAs('hello.xlsx');
    ExcelFile.Quit;
    ExcelFile := Unassigned;
  end;
end;

這段是Excel的操作，要測試可以執行多久，可以這樣寫：

Result := (RunLongTime( ExportXLSX));

剩下的就留給您體驗看看！

See also:

• System.SysUtils.TProc - RAD Studio API Documentation
• Calling existing excel file using OLE - delphi
• Guid文字列を得る