Check if the typeof(object) in a List is a reference type

Question

Hello,

this seems odd to me:

if(customerList.Count > 0)
{
   if(typeof(customerList[0]).IsReferenceType)
   {
      // do what I want
   }
}

How would you do it?

Answer 1

bool isReferenceType = !(customerList[0] is ValueType);

EDIT

Or are you looking for something like:

bool listIsOfReferenceTypeObjects = !myList.GetType().GetGenericArguments()[0].IsValueType;

Answer 2

1. To determine whether the first item in a list is an object of a reference type:

   bool isReferenceType = !(customerList[0] is ValueType);
   

2. To determine whether a list is a List<T> for some T that is a reference type:

   var listType = customerList.GetType();
   if (!listType.IsGeneric || listType.GetGenericTypeDefinition() != typeof(List<>))
       // It’s not a List<T>
       return null;
   return !listType.GetGenericArguments()[0].IsValueType;
   

Answer 3

You are probably trying to determine the actual type of the generic parameter of a generic collection. Like determining at runtime what is a T of a particular List<T>. Do this:

Type collectionType = typeof(customerList);
Type parameterType = collectionType.GetGenericArguments()[0];
bool isReference = !parameterType.IsValueType;

Answer 4

ok that worked and I get no exception, when the customerList is empty.

Type collectionType = customerList.GetType();
   Type parameterType = collectionType.GetGenericArguments()[0];
   bool isReference = !parameterType.IsValueType;

@Adesit you get a point because your sample was right except the first line :P