delphi BlockRead和BlockWrite读写文件

var

FromF, ToF: file;

NumRead, NumWritten: Integer;

Buf: array[1..2048] of Char;

begin

if OpenDialog1.Execute then begin

AssignFile(FromF, OpenDialog1.FileName);

Reset(FromF, 1); { Record size = 1 }

if SaveDialog1.Execute then { Display Save dialog box}

begin

AssignFile(ToF, SaveDialog1.FileName); { Open output file }

Rewrite(ToF, 1); { Record size = 1 }

Canvas.TextOut(10, 10, 'Copying ' + IntToStr(FileSize(FromF))

+ ' bytes...');

repeat

BlockRead(FromF, Buf, SizeOf(Buf), NumRead);

BlockWrite(ToF, Buf, NumRead, NumWritten);

until (NumRead = 0) or (NumWritten <> NumRead);

CloseFile(FromF);

CloseFile(ToF);

end;

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