Classes with indexes

[peter]

Hello guys,

I have the following class...

class myclass
{
    private ubyte[] Array;
}

...and i want to create an instance of this class and access the array as follows:

myclass mc = new myclass();
mc[0] = 100;

I was complety sure i saw this in the newsgroup but i can´t remember where exactly.
How is this "thing" called?
In the .NET framework i see it in almost every library.

I hope you guys get the idea, please help.