Breakpoints don't work when debugging a dll in ArcMap

Has this ever happened to you? It's really annoying, because one moment is working, the next one it's not. After doing some searching, it turns out there's an ArcMap configuration file -ArcMap.exe.config- that you need to modify. Just change the version from 2.0 to 4.0 and voila!

http://social.msdn.microsoft.com/Forums/en/vsdebug/thread/22d4c3d3-bf77-40ed-8b1b-64223019f3f1

ArcMap 10: Definition query not working on a layer with joins

It seems this was a defect on previous versions of ArcMap, but I recently came across it in ArcMap 10. I am not an ArcMap 10 expert, but I am pretty sure I set it up correctly.

A possible workaround is doing this in a different order: creating a definition query and then setting up the joins. This may work for most scenarios, except when the definition query is dependent on the joined data.

Calculatin Minimum/Maximum Latitude and Longitude

This is actually pretty simple. Just create a new field and then calculate it using this code:

dim pGeom as IGeometry
set pGeom = [shape]

and set the field value to:

Output = pGeom.Envelope.XMin

More info here