Question

I have defined a partial class with a property like this:

public partial class Item{    
    public string this[string key]
    {
        get
        {
            if (Fields == null) return null;
            if (!Fields.ContainsKey(key))
            {
                var prop = GetType().GetProperty(key);

                if (prop == null) return null;

                return prop.GetValue(this, null) as string;
            }

            object value = Fields[key];

            return value as string;
        }
        set
        {
            var property = GetType().GetProperty(key);
            if (property == null)
            {
                Fields[key] = value;
            }
            else
            {
                property.SetValue(this, value, null);
            }
        }
    }
}

So that i can do:

 myItem["key"];

and get the content of the Fields dictionary. But when i build i get:

“member names cannot be the same as their enclosing type”

Why?

Answer 1

Indexers automatically have a default name of Item – which is the name of your containing class. As far as the CLR is concerned, an indexer is just a property with parameters, and you can’t declare a property, method etc with the same name as the containing class.

One option is to rename your class so it’s not called Item. Another would be to change the name of the “property” used for the indexer, via [IndexerNameAttribute].

Shorter example of brokenness:

class Item
{
    public int this[int x] { get { return 0; } }
}

Fixed by change of name:

class Wibble
{
    public int this[int x] { get { return 0; } }
}

Or by attribute:

using System.Runtime.CompilerServices;

class Item
{
    [IndexerName("Bob")]
    public int this[int x] { get { return 0; } }
}