Determine if a property is a kind of array by reflection

Question

How can I determine if a property is a kind of array.

Example:

public bool IsPropertyAnArray(PropertyInfo property)
{
    // return true if type is I         


        

Answer 1

    public static bool IsGenericEnumerable(Type type)
    {
        return type.IsGenericType && 
            type.GetInterfaces().Any(
            ti => (ti == typeof (IEnumerable<>) || ti.Name == "IEnumerable"));
    }

    public static bool IsEnumerable(Type type)
    {
        return IsGenericEnumerable(type) || type.IsArray;
    }

Answer 2

You appear to be asking two different questions: whether a type is an array (e.g. string[]) or any collection type.

For the former, simply check property.PropertyType.IsArray.

For the latter, you have to decide what is the minimum criteria you want a type to conform to. For example, you could check for the non-generic IEnumerable by using typeof(IEnumerable).IsAssignableFrom(property.PropertyType). You can also use this for generic interfaces if you know the actual type of T, e.g. typeof(IEnumerable<int>).IsAssignableFrom(property.PropertyType).

Checking for the generic IEnumerable<T> or any other generic interface without knowing the value of T can be done by checking if property.PropertyType.GetInterface(typeof(IEnumerable<>).FullName) is not null. Note that I didn't specify any type for T in that code. You can do the same for IList<T> or any other type you're interested in.

For example you could use the following if you want to check for the generic IEnumerable<T>:

public bool IsPropertyACollection(PropertyInfo property) 
{ 
    return property.PropertyType.GetInterface(typeof(IEnumerable<>).FullName) != null;
} 

Arrays also implement IEnumerable, so they will also return true from that method.

Answer 3

Excluding String class as it qualifies as a collection because it implements IEnumerable<char>.

public bool IsPropertyACollection(this PropertyInfo property)
{
    return (!typeof(String).Equals(property.PropertyType) && 
        typeof(IEnumerable).IsAssignableFrom(property.PropertyType));
}

Answer 4

If you want to know if the property is an array, it's actually very easy:

property.PropertyType.IsArray;

edit

If you want to know if it's a type that implements IEnumerable, as do all "collection types", it's not very complicated either:

return property.PropertyType.GetInterface("IEnumerable") != null;

Answer 5

For me the following is not working,

return property.PropertyType.GetInterface(typeof(ICollection<>).FullName) != null;

Following was working,

typeof(ICollection<>).IsAssignableFrom(property.PropertyType.GetGenericTypeDefinition())

This is shortcut way to check ICollection<IInterface>orICollection<BaseClassInTree>

var property = request as PropertyInfo;

property.PropertyType.IsGenericType && (typeof(ICollection<>).IsAssignableFrom(property.PropertyType.GetGenericTypeDefinition())) && typeof().IsAssignableFrom(property.PropertyType.GenericTypeArguments[0])