另开帖子，文件流问题！怪

Question

读出时是一堆乱码，我到底错在哪儿？
unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Grids, StdCtrls;type
  TForm1 = class(TForm)
    Button1: TButton;
    Edit1: TEdit;
    StringGrid1: TStringGrid;
    Edit2: TEdit;
    Button2: TButton;
    Edit3: TEdit;
    Edit4: TEdit;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
  TestRec = record
    test1: string;
    test2: string;
    test3: single;
  end;  TestRecord = record
    test1: string;
    test2: array of TestRec;
  end;
var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.Button1Click(Sender: TObject);
var
  i, j: integer;
  testStream: TFileStream;
  Test: TestRecord;
begin
  Setlength(Test.test2, 3);
  test.test1 := '头信息';
  for i := Low(Test.test2) to High(Test.test2) do
  begin
    Test.test2[i].test1 := 'test1';
    Test.test2[i].test2 := 'test2';
    Test.test2[i].test3 := 3.2;
  end;
  testStream := TFileStream.Create('c:\test.txt', fmCreate);
  j := High(Test.test2) + 1;
  edit3.Text := inttostr(j);
  testStream.Position := 0;
  testStream.Write(j, sizeof(j));
  testStream.Write(test.test1, Sizeof(test.test1));
  for I := Low(test.test2) to High(test.test2) do
    testStream.Write(test.test2[I], SizeOf(Test.test2[I]));  FreeAndNil(testStream);end;procedure TForm1.Button2Click(Sender: TObject);
var
  i, j: integer;
  testStream: TFileStream;
  TestOpen: TestRecord;
begin
  testStream := TFileStream.Create('c:\test.txt', fmOpenRead);
  testStream.Position := 0;
  testStream.Read(j, sizeof(j));
  testStream.Read(TestOpen.test1, sizeOf(TestOpen.test1));
  Setlength(TestOpen.test2, j);
  for i := low(TestOpen.test2) to High(TestOpen.test2) do
  begin
    testStream.Read(TestOpen.test2[i], SizeOf(TestOpen.test2[I]));
    j:=1;
  end;  FreeAndNil(testStream);
  Edit1.Text := TestOpen.test1;
  edit4.Text := inttostr(j);
  for i := 0 to StringGrid1.RowCount - 1 do
  begin
    StringGrid1.Cells[1, i + 1] := '';
    StringGrid1.Cells[2, i + 1] := '';
    StringGrid1.Cells[3, i + 1] := '';
  end;
  for i := Low(TestOpen.test2) to High(TestOpen.test2) do
  begin
    StringGrid1.Cells[1, i + 1] := TestOpen.test2[i].test1;
    StringGrid1.Cells[2, i + 1] := TestOpen.test2[i].test2;
    StringGrid1.Cells[3, i + 1] := FormatFloat('0.00', TestOpen.test2[i].test3);
  end;
end;end.

Answer 1

//按你的思路改了一下，但是这样效率太低
procedure TForm1.Button1Click(Sender: TObject);
var
  len,i, j: integer;
  testStream: TFileStream;
  Test: TestRecord;
begin
  Setlength(Test.test2, 3);
  test.test1 := '头信息';
  for i := Low(Test.test2) to High(Test.test2) do
  begin
    Test.test2[i].test1 := 'test1';
    Test.test2[i].test2 := 'test2';
    Test.test2[i].test3 := 3.2;
  end;
  testStream := TFileStream.Create('c:\test.txt', fmCreate);
  j := High(Test.test2) + 1;
  edit3.Text := inttostr(j);
  testStream.Position := 0;
  testStream.Write(j, sizeof(j));
  len:=length(test.test1);
  testStream.Write(len,sizeof(len));
  testStream.Write(test.test1[1], len);  for I := Low(test.test2) to High(test.test2) do
  begin
   len:=length(test.test2[i].test1);
   testStream.Write(len,sizeof(len));
   testStream.Write(test.test2[i].test1[1], len);
   len:=length(test.test2[i].test2);
   testStream.Write(len,sizeof(len));
   testStream.Write(test.test2[i].test2[1], len);
   testStream.Write(test.test2[i].test3, sizeof(test.test2[i].test3));
  end;
  FreeAndNil(testStream); end;procedure TForm1.Button2Click(Sender: TObject);
var
  i, j,len: integer;
  testStream: TFileStream;
  TestOpen: TestRecord;
begin
  testStream := TFileStream.Create('c:\test.txt', fmOpenRead);
  testStream.Position := 0;
  testStream.Read(j, sizeof(j));
  testStream.Read(len, sizeof(len));
  setlength(testOpen.test1,len);
  testStream.Read(TestOpen.test1[1], len);
  Setlength(TestOpen.test2, j);
  i:=0;
  for i := low(TestOpen.test2) to High(TestOpen.test2) do
  begin
    testStream.Read(len, sizeof(len));
    Setlength(TestOpen.test2[i].test1,len);
    testStream.Read(TestOpen.test2[i].test1[1], len);
     testStream.Read(len, sizeof(len));
     Setlength(TestOpen.test2[i].test2,len);
    testStream.Read(TestOpen.test2[i].test2[1], len);
    testStream.Read(TestOpen.test2[i].test3, sizeof(TestOpen.test2[i].test3));  end;  FreeAndNil(testStream);
  Edit1.Text := TestOpen.test1;
  edit4.Text := inttostr(j);
  for i := 0 to StringGrid1.RowCount - 1 do
  begin
    StringGrid1.Cells[1, i + 1] := '';
    StringGrid1.Cells[2, i + 1] := '';
    StringGrid1.Cells[3, i + 1] := '';
  end;
  for i := Low(TestOpen.test2) to High(TestOpen.test2) do
  begin
    StringGrid1.Cells[1, i + 1] := TestOpen.test2[i].test1;
    StringGrid1.Cells[2, i + 1] := TestOpen.test2[i].test2;
    StringGrid1.Cells[3, i + 1] := FormatFloat('0.00', TestOpen.test2[i].test3);
  end;
end;

Answer 2

string 是不定長的, 所以, 寫沒問題, 讀的時候, 無法确認有多長, 修改如下就可:
  TestRec = record
    test1: string[255];
    test2: string[255];
    test3: single[255];
  end;
  TestRecord = record
    test1: string[255];
    test2: array of TestRec;
  end;

Answer 3

TestRec = record
    test1: string[255];
    test2: string[255];
    test3: single[255];
  end;
  TestRecord = record
    test1: string[255];
    test2: array of TestRec;
  end;

Answer 4

俺覚得：如果只是读和写,
用TFileStream不如用Textfile更簡易。