如何使用 Inno Setup 安装程序检查硬盘中是否有可用空间来安装应用程序

Question

我已经构建了一个安装程序来使用 Inno Setup 安装应用程序。但是我想显示一条错误消息，表明驱动器或路径中没有足够的空间，如果没有可用空间，我将在其中安装应用程序。

默认情况下，当硬盘或所选路径中没有可用空间时，我会内置 Inno 显示消息的功能。但它显示是和否按钮继续或取消。在这里，我想用 OK 按钮显示错误消息，当用户单击 OK 按钮时，它应该停止安装。请帮助我解决这个问题。我找不到任何方法来这样做。

Answer 1

要确定特定文件夹（在您的情况下为所选目录）的驱动器上的可用空间，您可以调用GetSpaceOnDisk或GetSpaceOnDisk64函数。它们之间的区别在于第一个能够以字节和兆字节为单位返回空间信息。后者仅以字节为单位返回此信息。对于以下示例，我选择了第一个提到的函数，因此您可以通过修改单个布尔参数来决定要以哪个单位进行操作：

[Code]
procedure ExitProcess(uExitCode: UINT);
  external 'ExitProcess@kernel32.dll stdcall';

function IsEnoughFreeSpace(const Path: string; MinSpace: Cardinal): Boolean;
var
  FreeSpace, TotalSpace: Cardinal;
begin
  // the second parameter set to True means that the function operates with
  // megabyte units; if you set it to False, it will operate with bytes; by
  // the chosen units you must reflect the value of the MinSpace paremeter
  if GetSpaceOnDisk(Path, True, FreeSpace, TotalSpace) then
    Result := FreeSpace >= MinSpace
  else
    RaiseException('Failed to check free space.');
end;

function NextButtonClick(CurPageID: Integer): Boolean;
begin
  Result := True;

  if CurPageID = wpSelectDir then
  begin
    // the second parameter in this function call is the expected min. space in
    // units specified by the commented parameter above; in this example we are
    // checking if there's at least 1 MB of free space on drive of the selected
    // directory; we need to extract a drive portion of the selected directory,
    // because it's probable that the directory won't exist yet when we check
    if not IsEnoughFreeSpace(ExtractFileDrive(WizardDirValue), 1) then
    begin
      MsgBox('There is not enough space on drive of the selected directory. ' +
        'Setup will now exit.', mbCriticalError, MB_OK);
      // in this input parameter you can pass your own exit code which can have
      // some meaningful value indicating that the setup process exited because
      // of the not enough space reason
      ExitProcess(666);
    end;
  end;
end;