How to know if a property is a type of List<MyClass>?

I have this in these classes.

public class MyClass:BaseClass
{ }

public class BaseClass
{ }

public class CollectionClass
{
public string SomeProperty {get; set;}

public List<MyClass> Collection {get; set;}
}


In my code I want to find out if the property in some object (e. g. CollectionClass) is a type of List<BaseClass> also I want to return true if the property is a type of List<MyClass>. The code below explains that.

CollectionClass

List<BaseClass>

List<MyClass>

public bool ContainsMyCollection(object obj)
{
foreach(var property in obj.GetType().GetProperties())
{
// Idk how to accomplish that
if(property isTypeof List<BaseClass>)
return true;
}
return false
}


List<MyClass>

List<BaseClass>

List<BaseClass> a = new List<MyClass>()

if(property.PropertyType == typeof(List<BaseClass>))

1 Answer
1

You need to check if you have a closed type of List<>. This can be done like so:

List<>

if(property.PropertyType.IsGenericType
&& property.PropertyType.GetGenericTypeDefinition() == typeof(List<>))


and then you have to check if the generic argument (the T part of List<T>) is assignable to your base type:

T

List<T>

if (typeof(BaseClass).IsAssignableFrom(property.PropertyType.GetGenericArguments()[0]))


Putting that together, you get this:

public bool ContainsMyCollection(object obj)
{
foreach(var property in obj.GetType().GetProperties())
{
// Idk how to accomplish that
if(property.PropertyType.IsGenericType
&& property.PropertyType.GetGenericTypeDefinition() == typeof(List<>)
&& typeof(BaseClass).IsAssignableFrom(property.PropertyType.GetGenericArguments()[0]))
{
return true;
}
}
return false;
}


Note that, as explained in the comments, List<MyClass> isn't derived from List<BaseClass>, even if MyClass is derived from BaseClass. So, for example, List<BaseClass> a = new List<MyClass>(); will fail. That falls outside the scope of your question, but I figured I'd give you the heads up in case you didn't already know.

List<MyClass>

List<BaseClass>

MyClass

BaseClass

List<BaseClass> a = new List<MyClass>();

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