Delphi中拷贝文件

{方法一：用File stream }

Procedure FileCopy( Const sourcefilename, targetfilename: String );
Var
  S, T: TFileStream;
Begin
  S := TFileStream.Create( sourcefilename, fmOpenRead );
  try
    T := TFileStream.Create( targetfilename,fmOpenWrite or fmCreate);
    try
      T.CopyFrom(S, S.Size ) ;
    finally
      T.Free;
    end;
  finally
    S.Free;
  end;
end;

{ 方法二：使用内存块进行读写 }

procedure FileCopy(const FromFile, ToFile: string);
var
  FromF, ToF: file;
  NumRead, NumWritten: Word;
  Buf: array[1..2048] of Char;
begin
  AssignFile(FromF, FromFile);
  Reset(FromF, 1);
  AssignFile(ToF, ToFile);
  Rewrite(ToF, 1);
  repeat
    BlockRead(FromF, Buf, SizeOf(Buf), NumRead);
    BlockWrite(ToF, Buf, NumRead, NumWritten);
  until (NumRead = 0) or (NumWritten <> NumRead);
  CloseFile(FromF);
  CloseFile(ToF);
end;
end

{方法三：使用LZExpand.DLL中的函数LZCopy }

procedure CopyFile(FromFileName, ToFileName: string);
var
  FromFile, ToFile: File;
begin
  AssignFile(FromFile, FromFileName);
  AssignFile(ToFile, ToFileName);
  Reset(FromFile);
  try
    Rewrite(ToFile);
    try
      if LZCopy(TFileRec(FromFile).Handle,TFileRec(ToFile).Handle) < 0 then
         raise EInOutError.Create('Error using LZCopy')
    finally
      CloseFile(ToFile);
    end;
  finally
    CloseFile(FromFile);
  end;
end;