Identifying a custom indexer using reflection in C#

You can also look for index parameters, using the the PropertyInfo.GetIndexParameters method, if it returns more than 0 items, it's an indexed property:

foreach (PropertyInfo pi in typeof(MyClass).GetProperties())
{
    if (pi.GetIndexParameters().Length > 0)
    {
       // Indexed property...
    }
}

Look for the DefaultMemberAttribute defined at type level.

(This used to be IndexerNameAttribute, but they seem to have dropped it)

    static void Main(string[] args) {

        foreach (System.Reflection.PropertyInfo propertyInfo in typeof(System.Collections.ArrayList).GetProperties()) {

            System.Reflection.ParameterInfo[] parameterInfos = propertyInfo.GetIndexParameters();
            // then is indexer property
            if (parameterInfos.Length > 0) {
                System.Console.WriteLine(propertyInfo.Name);
            }
        }


        System.Console.ReadKey();
    }