System.Diagnostics.DebuggerBrowsable attribute

This attribute can be applied to fields or properties of an object, to determine how they are displayed in the Visual Studio debugger windows.The constructor has a single parameter, of type DebuggerBrowsableState. this is an enum with three values: Never, Collapsed and RootHidden. The "default" for objects without this attribute is to be shown as Collapsed.

As an example, an object I've contrived that looks like this:

would be displayed in the debugger like this:

We can hide properties and fields from the debugger by decorating them with the attribute, initialised with "Never" - note the usage on a private field, which enforces the concept of encapsulation; a principle that from now on I'll be calling ASYPIP (Avoid showing your privates in public) 

This object is displayed like this:

The last value of DebuggerBrowsableState is RootHidden - this does not show the property or field itself, but shows its child elements as direct descendants of the object. So, an object decorated like this...

... will be displayed like this:

.