到DELPHI7需要XE2代码 - 德尔福。 使用WinInet下载文件(Delphi - XE

注：我只希望使用WININET，不URLMON-urldownloadtofile。

好吧，我有以下的代码完全在XE2下载文件：

procedure DownloadFile(URL: string; Path: string);
const
  BLOCK_SIZE = 1024;
var
  InetHandle: Pointer;
  URLHandle: Pointer;
  FileHandle: Cardinal;
  BytesRead: Cardinal;
  DownloadBuffer: Pointer;
  Buffer: array [1 .. BLOCK_SIZE] of byte;
  BytesWritten: Cardinal;
begin
  InetHandle := InternetOpen(PWideChar(URL), 0, 0, 0, 0);
  URLHandle := InternetOpenUrl(InetHandle, PWideChar(URL), 0, 0, 0, 0);
  FileHandle := CreateFile(PWideChar(Path), GENERIC_WRITE, FILE_SHARE_WRITE, 0,
CREATE_NEW, FILE_ATTRIBUTE_NORMAL, 0);
  DownloadBuffer := @Buffer;
  repeat
    InternetReadFile(URLHandle, DownloadBuffer, BLOCK_SIZE, BytesRead);
    if not WriteFile(FileHandle, DownloadBuffer, BytesRead, BytesWritten, 0) or
  (BytesWritten <> BytesRead) then
      RaiseLastOSError;
  until BytesRead < BLOCK_SIZE;
  CloseHandle(FileHandle);
  InternetCloseHandle(URLHandle);
  InternetCloseHandle(InetHandle);
end;

上面的代码的学分去jachguate 。 他编辑我的代码来纠正它，我向他表示感谢。

现在，这个代码只是正常工作下德尔福XE2。 我尝试使用它的Delphi 7下，它不能正常工作。 这似乎存储相同的“行”或“字节序列”的文件过来，翻了几十倍。

以下是上面的代码，我attemted在Delphi 7使用的两种改革中 - 这两者都不工作正常。

procedure DownloadFile(URL: string; Path: string);
const
  BLOCK_SIZE = 1024;
var
  InetHandle: Pointer;
  URLHandle: Pointer;
  FileHandle: Cardinal;
  BytesRead: Cardinal;
  DownloadBuffer: Pointer;
  Buffer: array [1 .. BLOCK_SIZE] of byte;
  BytesWritten: Cardinal;
begin
  InetHandle := InternetOpen(PChar(URL), 0, 0, 0, 0);
  URLHandle := InternetOpenUrl(InetHandle, PChar(URL), 0, 0, 0, 0);
  FileHandle := CreateFile(PChar(Path), GENERIC_WRITE, FILE_SHARE_WRITE, 0,
CREATE_NEW, FILE_ATTRIBUTE_NORMAL, 0);
  DownloadBuffer := @Buffer;
  repeat
    InternetReadFile(URLHandle, DownloadBuffer, BLOCK_SIZE, BytesRead);
    if not WriteFile(FileHandle, DownloadBuffer, BytesRead, BytesWritten, 0) or
  (BytesWritten <> BytesRead) then
      RaiseLastOSError;
  until BytesRead < BLOCK_SIZE;
  CloseHandle(FileHandle);
  InternetCloseHandle(URLHandle);
  InternetCloseHandle(InetHandle);
end;

---

procedure DownloadFile(URL: string; Path: string);
const
  BLOCK_SIZE = 1024;
var
  InetHandle: Pointer;
  URLHandle: Pointer;
  FileHandle: Cardinal;
  BytesRead: Cardinal;
  DownloadBuffer: Pointer;
  Buffer: array [1 .. BLOCK_SIZE] of byte;
  BytesWritten: Cardinal;
begin
  InetHandle := InternetOpen(PAnsiChar(URL), 0, 0, 0, 0);
  URLHandle := InternetOpenUrl(InetHandle, PAnsiChar(URL), 0, 0, 0, 0);
  FileHandle := CreateFile(PAnsiChar(Path), GENERIC_WRITE, FILE_SHARE_WRITE, 0,
CREATE_NEW, FILE_ATTRIBUTE_NORMAL, 0);
  DownloadBuffer := @Buffer;
  repeat
    InternetReadFile(URLHandle, DownloadBuffer, BLOCK_SIZE, BytesRead);
    if not WriteFile(FileHandle, DownloadBuffer, BytesRead, BytesWritten, 0) or
  (BytesWritten <> BytesRead) then
      RaiseLastOSError;
  until BytesRead < BLOCK_SIZE;
  CloseHandle(FileHandle);
  InternetCloseHandle(URLHandle);
  InternetCloseHandle(InetHandle);
end;

只有编辑的东西是数据类型的转换。 例如，一个“PChar类型”被使用，例如，两个“PAnsiChar”被使用。

Answer 1:

你得到的垃圾文件，因为你需要取消引用指针DownloadBuffer使用^字符，所以解决您的方法只是将这段代码

WriteFile(FileHandle, DownloadBuffer, BytesRead, BytesWritten, 0)

这样

WriteFile(FileHandle, DownloadBuffer^, BytesRead, BytesWritten, 0)

顺便说一句，记得try..finally块添加到您的功能，以确保当异常发生时释放手柄。

文章来源: Delphi - XE2 code to Delphi7 needed. Using wininet to download a file