.net - “检查”功能在 Inno Setup 中多次执行

Question

我是 Inno Setup 脚本的新手，我正在尝试使用以下代码作为先决条件安装 .NET framework 3.5。 Check函数执行多次。有人可以帮我理解为什么吗？

注意:以下代码中的所有其他部分( Setup 、 Icons 等)都有正确的内容。

[Files]
Source: "Frameworks\dotnetfx35setup.exe"; DestDir: {tmp}; Flags: deleteafterinstall; \
    BeforeInstall: Install35Framework; Check: Framework35IsNotInstalled

[Code]
function IsDotNetDetected(version: string; service: Cardinal): boolean;
begin
  Result := { ... };
end;

function Framework35IsNotInstalled: Boolean;
begin
  if IsDotNetDetected('v3.5', 1) then
  begin
    MsgBox('Framework35IsNotInstalled: FALSE ', mbConfirmation, MB_YESNO);
    Result := False;
  end else begin
    MsgBox('Framework35IsNotInstalled: TRUE ', mbConfirmation, MB_YESNO);
    Result := True;
  end;
end; 

procedure Install35Framework;
begin
  { ... }
end;

Answer 1

报价Check parameter documentation :

Setup might call each check function several times, even if there's only one entry that uses the check function. If your function performs a lengthy piece of code, you can optimize it by performing the code only once and 'caching' the result in a global variable.

所以行为是按设计的。

由于您的代码非常简单，我什至认为它不需要任何优化。完全没问题，如果它运行几次。

如果不是，您可以像这样优化它:

var
  Framework35IsNotInstalledCalled: Boolean; 
  Framework35IsNotInstalledResult: Boolean;

function Framework35IsNotInstalled: Boolean;
begin
  if not Framework35IsNotInstalledCalled then
  begin
    Framework35IsNotInstalledResult := IsDotNetDetected('v3.5', 1);
    Framework35IsNotInstalledCalled := True;
  end;

  Result := Framework35IsNotInstalledResult;
end;