[英]Finding out if a type implements a generic interface
Let's say I have a type, MyType. 假设我有一个类型MyType。 I want to do the following:
我想做以下事情:
It seems like the way to do this is GetInterface(), but that only lets you search by a specific name. 看起来这样做的方法是GetInterface(),但这只允许您按特定名称进行搜索。 Is there a way to search for "all interfaces that are of the form IList" (If possible it woudl also be useful if it worked if the interface was a subinterface of IList.)
有没有办法搜索“IList形式的所有接口”(如果可能的话,如果接口是IList的子接口,它也会有用。)
Related: How to determine if a type implements a specific generic interface type 相关: 如何确定类型是否实现特定的通用接口类型
// this conditional is necessary if myType can be an interface,
// because an interface doesn't implement itself: for example,
// typeof (IList<int>).GetInterfaces () does not contain IList<int>!
if (myType.IsInterface && myType.IsGenericType &&
myType.GetGenericTypeDefinition () == typeof (IList<>))
return myType.GetGenericArguments ()[0] ;
foreach (var i in myType.GetInterfaces ())
if (i.IsGenericType && i.GetGenericTypeDefinition () == typeof (IList<>))
return i.GetGenericArguments ()[0] ;
Edit: Even if myType
implements IDerivedFromList<>
but not directly IList<>
, IList<>
will show up in the array returned by GetInterfaces()
. 编辑:即使
myType
实现IDerivedFromList<>
但不直接IList<>
IList<>
将通过返回的数组中显示GetInterfaces()
Update: added a check for the edge case where myType
is the generic interface in question. 更新:添加了对边缘情况的检查,其中
myType
是有问题的通用接口。
Using reflection (and some LINQ) you can easily do this: 使用反射(和一些LINQ),您可以轻松地执行此操作:
public static IEnumerable<Type> GetIListTypeParameters(Type type)
{
// Query.
return
from interfaceType in type.GetInterfaces()
where interfaceType.IsGenericType
let baseInterface = interfaceType.GetGenericTypeDefinition()
where baseInterface == typeof(IList<>)
select interfaceType.GetGenericArguments().First();
}
First, you are getting the interfaces on the type and filtering out only for those that are a generic type. 首先,您将获取该类型的接口,并仅过滤掉那些通用类型的接口。
Then, you get the generic type definition for those interface types, and see if it is the same as IList<>
. 然后,您将获得这些接口类型的泛型类型定义,并查看它是否与
IList<>
相同。
From there, it's a simple matter of getting the generic arguments for the original interface. 从那里,获得原始接口的泛型参数是一件简单的事情。
Remember, a type can have multiple IList<T>
implementations, which is why the IEnumerable<Type>
is returned. 请记住,类型可以有多个
IList<T>
实现,这就是返回IEnumerable<Type>
原因。
public static bool Implements<I>(this Type type) where I : class
{
if (!typeof(I).IsInterface)
{
throw new ArgumentException("Only interfaces can be 'implemented'.");
}
return typeof(I).IsAssignableFrom(type);
}
As a helper method extension 作为辅助方法的扩展
public static bool Implements<I>(this Type type, I @interface) where I : class
{
if(((@interface as Type)==null) || !(@interface as Type).IsInterface)
throw new ArgumentException("Only interfaces can be 'implemented'.");
return (@interface as Type).IsAssignableFrom(type);
}
example usage: 示例用法:
var testObject = new Dictionary<int, object>();
result = testObject.GetType().Implements(typeof(IDictionary<int, object>)); // true!
Using Anton Tykhyy's proposal, here is a small Extension Method to check if some type implements a generic interface with one given generic type parameters: 使用Anton Tykhyy的提议,这里有一个小的扩展方法来检查某个类型是否使用一个给定的泛型类型参数实现泛型接口:
public static class ExtensionMethods
{
/// <summary>
/// Checks if a type has a generic interface.
/// For example
/// mytype.HasGenericInterface(typeof(IList<>), typeof(int))
/// will return TRUE if mytype implements IList<int>
/// </summary>
public static bool HasGenericInterface(this Type type, Type interf, Type typeparameter)
{
foreach (Type i in type.GetInterfaces())
if (i.IsGenericType && i.GetGenericTypeDefinition() == interf)
if (i.GetGenericArguments()[0] == typeparameter)
return true;
return false;
}
}
If i understand your question correctly, this is what you are trying to do. 如果我理解你的问题,这就是你想要做的。 If not, please explain further.
如果没有,请进一步解释。
public class MyType : ISomeInterface
{
}
MyType o = new MyType();
if(o is ISomeInterface)
{
}
edit: if you change your question, please add the fact that you edited..because now my answer looks like it doesn't belong. 编辑:如果你改变了你的问题,请添加你编辑的事实。因为现在我的回答看起来不属于你。
In that case, here is a very large LINQ 在这种情况下,这是一个非常大的LINQ
var item = typeof(MyType).GetInterfaces()
.Where(x => x.IsGenericType && x.GetGenericTypeDefinition() == typeof(IList<>))
.Select(t => t.GetGenericArguments().First())
.FirstOrDefault();
if( item != null )
//it has a type
Type[] typeArray2 = c.GetInterfaces();
for (int num2 = 0; num2 < typeArray2.Length; num2++)
{
if (this == typeArray2[num2])
{
return true;
}
}
-- http://www.hanselman.com/blog/DoesATypeImplementAnInterface.aspx - http://www.hanselman.com/blog/DoesATypeImplementAnInterface.aspx
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