[Mono-list] A question about interfaces

Rodolfo Campero rodolfocampero@hotmail.com
Sat, 07 Feb 2004 02:44:48 +0000

Hello all,

I have a question about interfaces. I tried to compile the following 

namespace InterfaceTests {
	interface ITop {
		int Count { get; }

	interface ILeft: ITop {}

	interface IRight: ITop {}

	interface IBottom: ILeft, IRight {}

	class Test {
		public static void Main () {}

		public void Testing (IBottom test) {
			int a = test.Count;

but I got a CS0122 error:

	interfaces.cs(16) error CS0122: `InterfaceTests.IBottom.Count' is 
inaccessible due to its protection level
	Compilation failed: 1 error(s), 0 warnings

I wonder why IBottom.Count is inaccessible, given the fact that neither 
ILeft nor IRight hide this property.

I've read the documentation, and in ECMA-334 C# Language Specification, 
section 20.1.2: Base interfaces, there is a similar example involving 
IControl, ITextBox, IListBox and IComboBox, and the example states:
"the IComboBox interface above inherits members SetText and SetItems as well 
as Paint." In the example, Paint is defined in the basic interface 
And then in 20.2, "The members of an interface are the members inherited 
from the base interfaces and the members declared by the interface itself."
>From 20.4.2: "When a class implements multiple interfaces that have the same 
base interface, there can be only one implementation of the base interface."

Apparently the property Count in my example shouldn't be hidden in the 
interface IBottom, yet I'm getting an error. Is this a bug in mcs or am I 
missing something?


Rodolfo Campero

PS: BTW, is this the right list to ask this kind of questions, or would 
mono-devel-list be more appropriate?

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