Delphi 使用 Stream reader 的奇怪问题

Question

所以我有一个二进制文件，我正在读取一个 2 字节的字值，该值是一个 Int16 = 43140，但是每当我在 Delphi 中读取它时，它 returns 为 43104，我写了代码在 C# 中读取它只是为了测试它读取正确它只是在 Delphi 中它读取不正确，看起来 0 和 4 由于某种原因正在移动位置。

  TMyHeader= packed record
     Value1       :String[20];
     Value2       :Word; // Is 43140 but reading as 43104
     Value3       :Word;
     Value4       :Word; // Is 43140 but reading as 43104
  end;

FileRead (fhandle, header, sizeof(MyHeader));

Answer 1

您的代码没有使用 Stream reader，而且读取文件的问题完全不可能。这是使用 TFileStream 成功读取和写入记录而不以任何方式更改值的示例。（很明显，您必须首先更改 TestFile 常量以指向系统上有效的可写位置。）

program Project1;

{$APPTYPE CONSOLE}

uses
  SysUtils, Classes;

type
  TMyHeader = packed record
    Value1: String[20];
    Value2: Word;
    Value3: Word;
    Value4: Word;
  end;

var
  MyHeader: TMyHeader;
  Stream: TFileStream;

const
  TestFile = 'E:\TempFiles\Testheader.bin';

begin
  // Initialize the record
  MyHeader.Value1 := 'Testing One Two';
  MyHeader.Value2 := 43140;
  MyHeader.Value3 := 12345;
  MyHeader.Value4 := 43140;

  // Show what it contains. The `[]` brackets are to clearly delimit Value1
  WriteLn(Format('Before write: [%s] %d %d %d', 
                  [MyHeader.Value1, MyHeader.Value2, MyHeader.Value3, MyHeader.Value4]));

  // Write it to the stream.
  Stream := TFileStream.Create(TestFile, fmCreate, fmShareDenyNone);
  try
    Stream.Write(MyHeader, SizeOf(TMyHeader));
  finally
    Stream.Free;
  end;

  // Clear the contents of MyHeader before reading back, and show the empty values
  FillChar(MyHeader, SizeOf(TMyHeader), 0);
  WriteLn(Format('Before read: [%s] %d %d %d', 
                 [MyHeader.Value1, MyHeader.Value2, MyHeader.Value3, MyHeader.Value4]));
  Stream := TFileStream.Create(TestFile, fmOpenRead, fmShareDenyNone);
  try
    Stream.Read(MyHeader, SizeOf(TMyHeader));
  finally
    Stream.Free;
  end;
  // Output what we've read back in to verify it is correct
  WriteLn(Format('After read: [%s] %d %d %d', 
                 [MyHeader.Value1, MyHeader.Value2, MyHeader.Value3, MyHeader.Value4]));
  Readln;
end.

Delphi 使用 Stream reader 的奇怪问题

Curious issue in Delphi using Stream reader

delphi

delphi-2007