C#泛型方法并从xml返回在方法中创建的参数化类型的对象
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原文地址: http://stackoverflow.com/questions/919169/
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C# Generics methods and returning a object of a parameterized type created in the method from xml
提问by theringostarrs
I have a method where I would like to return an object instance of parameterized type T ie. Foo<T>.
我有一个方法，我想返回一个参数化类型 T 的对象实例，即。Foo<T>.
The type T is instantiated within the method using GetType(), from a string element in an XML file. Since neither the class or method knows about it before it is created, I cant parameterize either.
类型 T 在方法中使用GetType(), 从 XML 文件中的字符串元素实例化。由于在创建之前类或方法都不知道它，我也不能参数化。
Is there a way I can return an object of type Foo<T>from the non-generic method?
有没有办法可以Foo<T>从非泛型方法返回类型对象？
EDIT: That is a method signature such as:
编辑：这是一个方法签名，例如：
public Foo<T> getFooFromXml(string name) {
where the type is created inside, and the method and class are both non-generic?
类型是在里面创建的，方法和类都是非泛型的？
采纳答案by Josh
In response to your edit:
回应您的编辑：
That method signature isn't valid anyway. You need to know T at compile time in order to return Foo from a method. Consider my suggestion in the comments on my last answer where you would have a separate interface IFoo that Foo implements.
无论如何，该方法签名是无效的。您需要在编译时知道 T 才能从方法中返回 Foo。考虑我在上一个答案的评论中的建议，您将拥有一个单独的接口 IFoo Foo 实现。
class Foo<T> : IFoo {
public T DoSomething() {
...
}
object IFoo.DoSomething() {
return DoSomething();
}
}
interface IFoo {
object DoSomething();
}
回答by Josh
Yeah, basically you have to get the open generic type and create a closed generic type.
是的，基本上你必须获得开放的泛型类型并创建一个封闭的泛型类型。
Type openType = typeof(Foo<>);
Type closedType = openType.MakeGenericType(typeof(string));
return Activator.CreateInstance(closedType); // returns a new Foo<string>
EDIT: Note that I used typeof(Foo<>) above, I intentionally left the angle brackets empty.
编辑：请注意，我在上面使用了 typeof(Foo<>)，我故意将尖括号留空。
