Indexers can't have void type
The return type of an indexer property cannot be void. An indexer must return a value.
The following sample generates CS0620:
class MyClass { public static void Main() { MyClass test = new MyClass(); System.Console.WriteLine(test[2]); } void this [int intI] { // CS0620, return type cannot be void get { // will need to return some value } } }