使用 Unity 改变构造函数注入的字符串参数

Question

我的目标是改变字符串参数：

Container
 .RegisterInstance<string>("us", @"\\ad1\accounting$\Xml\qb_us.xml")
 .RegisterInstance<string>("intl", @"\\ad1\accounting$\Xml\qb_intl.xml");

driver = Container.Resolve<LoaderDriver>(args[1]); // "us" or "intl"

这会导致：

Resolution of the dependency failed, type = "QuickBooksService.LoaderDriver", name = "intl".
Exception occurred while: while resolving.
Exception is: InvalidOperationException - The type String cannot be constructed. You must configure the container to supply this value.
-----------------------------------------------
At the time of the exception, the container was:

  Resolving QuickBooksService.LoaderDriver,intl
  Resolving parameter "reader" of constructor QuickBooksService.LoaderDriver(QuickBooksService.LoaderInputReader reader, QuickBooksService.ILoader[] loaders)
    Resolving QuickBooksService.LoaderInputReader,(none)
    Resolving parameter "inputFile" of constructor QuickBooksService.LoaderInputReader(System.String inputFile, AccountingBackupWeb.Models.AccountingBackup.Company company, Qu
ickBooksService.eTargets targets)
      Resolving System.String,(none)

这显然是错误的，但这是我可以让它工作的唯一方法：

if (args[1] == "us")
    Container
        .RegisterType<LoaderInputReader>(
            new InjectionConstructor(
                @"\\ad1\accounting$\Xml\qb_us.xml",
                new ResolvedParameter<Company>(),
                new ResolvedParameter<eTargets>()
            )
        )
    ;
else if (args[1] == "intl")
    Container
        .RegisterType<LoaderInputReader>(
            new InjectionConstructor(
                @"\\ad1\accounting$\Xml\qb_intl.xml",
                new ResolvedParameter<Company>(),
                new ResolvedParameter<eTargets>()
            )
        )
    ;
else
    throw new Exception("invalid company");

driver = Container.Resolve<LoaderDriver>();

Answer 1

像这样的东西应该可以工作：

container
    .RegisterType<LoaderInputReader>(
        "us",
        new InjectionConstructor(
            @"\\ad1\accounting$\Xml\qb_us.xml",
            new ResolvedParameter<Company>(),
            new ResolvedParameter<eTargets>()));
container
    .RegisterType<LoaderInputReader>(
        "intl",
        new InjectionConstructor(
            @"\\ad1\accounting$\Xml\qb_intl.xml",
            new ResolvedParameter<Company>(),
            new ResolvedParameter<eTargets>()));

这为 LoaderInputReader 的每个注册命名。现在你可以这样解决：

var us = container.Resolve<LoaderInputReader>("us");
var intl = container.Resolve<LoaderInputReader>("intl");

Answer 2

也许你可以改变

driver = Container.Resolve<LoaderDriver>(args[1]); // "us" or "intl"

这

driver = Container.Resolve<LoaderDriver>(Container.Resolve<string>(args[1]))

利用了 解决带有名称的重载，在您的情况下，名称来自您的参数。