查找实现具有特定T类型的某个通用接口的所有类型 [英] Find all types implementing a certain generic interface with specific T type

问题描述

我有几个继承自抽象类BrowsingGoal 的类。其中一些实现了一个名为 ICanHandleIntent< TPageIntent>的接口。其中TPageIntent：PageIntent 。

给出一个具体的例子：

  public class Authenticate：BrowsingGoal ，ICanHandleIntent< AuthenticationNeededIntent> 
 {
 ... 
} 
  

现在我想使用 AuthenticationNeededIntent 扫描实现 ICanHandleIntent 的所有类型的CurrentDomain程序集。这是我迄今为止的，但它似乎没有发现任何东西：

 受保护的BrowsingGoal FindNextGoal（PageIntent意图）
 {
 //找到实现ICanHandleIntent< specific PageIntent>的目标
 var goalHandler = AppDomain.CurrentDomain 
 .GetAssemblies（）
 .SelectMany（assembly => assembly.GetTypes（））
 .FirstOrDefault（t => t.IsAssignableFrom （typeof（BrowsingGoal）））&& 
 t.GetInterfaces（）。Any（x => 
 x.IsGenericType&& 
 x.IsAssignableFrom（typeof（ICanHandleIntent< >））&& 
 x.GetGenericTypeDefinition（）== intent.GetType（）））; 
 
 if（goalHandler！= null）
返回Activators.CreateInstance（goalHandler）作为BrowsingGoal; 
} 
  

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<这个条件是不正确的：

  x.IsAssignableFrom（typeof （ICanHandleIntent<>））
  

实现通用接口实例的类型不能从通用接口定义本身，其中 ICanHandleIntent<> 表示。

您需要的是

  x.GetGenericTypeDefinition（）== typeof（ICanHandleIntent<>）
  

检查类型参数也是错误的。它应该是

  x.GetGenericArguments（）[0] == intent.GetType（）
  
 $ b $ p $因为你正在寻找类型参数，即在通用名称后面的三角括号中的类型。
 
I have several classes inheriting from abstract class BrowsingGoal. Some of these implement an interface called ICanHandleIntent<TPageIntent> where TPageIntent: PageIntent. 

To give a concrete example:
public class Authenticate : BrowsingGoal, ICanHandleIntent<AuthenticationNeededIntent>
{
    ...
}
Now I would like to scan the CurrentDomain's assemblies for all types implementing the ICanHandleIntent with the AuthenticationNeededIntent. This is what I have so far but it doesn't seem to find anything:
protected BrowsingGoal FindNextGoal(PageIntent intent)
{
    // Find a goal that implements an ICanHandleIntent<specific PageIntent>
    var goalHandler = AppDomain.CurrentDomain
        .GetAssemblies()
        .SelectMany(assembly => assembly.GetTypes())
        .FirstOrDefault(t => t.IsAssignableFrom((typeof (BrowsingGoal))) &&
                                t.GetInterfaces().Any(x =>
                                    x.IsGenericType &&
                                    x.IsAssignableFrom(typeof (ICanHandleIntent<>)) &&
                                    x.GetGenericTypeDefinition() == intent.GetType()));

    if (goalHandler != null)
        return Activator.CreateInstance(goalHandler) as BrowsingGoal;
}
Some help would be very appreciated!
解决方案
This condition is incorrect:
x.IsAssignableFrom(typeof(ICanHandleIntent<>))
a type implementing an instance of a generic interface is not assignable from the generic interface definition itself, which ICanHandleIntent<> represents.

What you want instead is
x.GetGenericTypeDefinition() == typeof(ICanHandleIntent<>)
The check for the type parameter is also wrong. It should be
x.GetGenericArguments()[0] == intent.GetType()
because you are looking for the type argument, i.e. the type in triangular brackets following the generic name.

                        
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