In my latest instalment of the Debugging tip of the week, I’d like to introduce the debugging attributes. These handy attributes, found in the System.Diagnostics namespace, can be applied to your source code in order to control the way the debugger steps through it. Some of the debugging attributes can also be used to customise the data tips that appear when you hover over a variable in Break mode, or view it in a Watch window.

The first attribute we will cover is the DebuggerBrowsable attribute. This attribute takes a DebuggerBrowsableState enumeration value as a parameter that determines how the member is displayed in the variable tree. In the following code snippet, the field Orders in the Customer class is set to Collapsed:

using System.Diagnostics;

public class Customer
{
   [DebuggerBrowsable(DebuggerBrowsableState.Collapsed)]
   public List<Order> Orders;
}

Collapsed is the default DebuggerBrowsableState that you would normally see in Visual Studio. If you apply this to a member then it will be displayed, but not expanded by default, as shown below.

The following shows the same snippet with DebuggerBrowsable set to the RootHidden value. In this case the actual Orders item does not appear as a top-level entry in the data window, just the contents of the collection.

Finally, the Never value will hide the member completely from the data window. This can be quite useful if you want to hide your private properties. You can see the effect of this below, where the Orders member does not appear at all.

In .NET Framework 2.0, the DebuggerBrowsable attribute is only interpreted by the C# debugger and has no effect when it is applied to Visual Basic code. This limitation has been removed in newer versions of the .NET Framework.