How do I check if a given value is a generic list?

 bool isList = o.GetType().IsGenericType 
                && o.GetType().GetGenericTypeDefinition() == typeof(IList<>));

using System.Collections;

if(value is IList && value.GetType().IsGenericType) {

}

For you guys that enjoy the use of extension methods:

public static bool IsGenericList(this object o)
{
    var oType = o.GetType();
    return (oType.IsGenericType && (oType.GetGenericTypeDefinition() == typeof(List<>)));
}

So, we could do:

if(o.IsGenericList())
{
 //...
}