The Moth

Dotnet projects have at least two configurations: Debug and Release. Part of the configuration is the definition of two compilation constants: DEBUG and TRACE. For Debug configurations, both constants are on; for Release, only TRACE is on. I always turn TRACE off as well, and I advice you to do the same (however, that is not the point of this blog entry).

You can tweak these in your project properties (they are represented by checkboxes) and you can also add your own in the textbox offered or you can define them in code (#define or #const, depending on your language of choice). An example of why you would add a compilation constant is for cross platform development, as detailed before.

For conditional compilation you use #if. In C#, the code that does not apply gets greyed out. This is really sweet and somehow I thought it was added to the VB2005 IDE, but unfortunaly I realised recently it wasn't :-(
Go vote for it (maybe it will make the Orcas release).

In VS2005 we find a few additional conditional compilation symbols that are not in VS.NET 2003 (applicable or not, based on what project type you chose and what language you are developing in):
DEBUG
TRACE
CODE_ANALYSIS
PocketPC
WindowsCE
Smartphone
TARGET
CONFIG
VBC_VER
_MyType

I'll let you figure out what each one is used for and the potential values they can have ;-)