The answer below was written back in 2010. In C# 6 (released in 2015) you can write read-only automatically-implemented properties:
// This can only be assigned to in a constructor
public int Foo { get; }
You’re absolutely right. Properly read-only automatically implemented properties are currently impossible. Making the setter private isn’t the same thing, regardless of what some books and MSDN might say 🙂
If I ruled the world, this would not be the case. When I see some of the language designers at NDC 2010 in June (please come along!) I intend to try to persuade, bribe, cajole and generally make a nuisance of myself until they agree. It’s just one wafer-thin feature, after all.
Looking at that MSDN article, the text itself doesn’t say that it creates a read-only automatic property. It creates an immutable type using an automatic property, and that’s correct. The only problematic bits are the comments saying
// Read-only properties.
… which are definitely wrong. The framework agrees with us:
var prop = typeof(Contact).GetProperty("Name");
Console.WriteLine(prop.CanWrite); // Prints True