This post has been a long time coming, as I previously announced I would start this series following my user group presentation back in June. There’s a myriad of reasons why I let it go so long, however the impending release of Professional Visual Studio 2008 has kicked me into action.

For the first of what will become an ongoing weekly series of debugging tips I’d like to start off with one of my favourite windows in the whole of Visual Studio - the Immediate Window. This useful window can be used during both debugging and at design-time. The window is displayed using the keyboard shortcut Ctrl+Alt+I, or by selecting it from the Debug->Windows menu. You can also type immed in the Command window and it will display and switch focus to the immediate window.

Quite often when you’re debugging an application, you’ll want to evaluate a simple expression either to test a bit of functionality or to remind yourself of how something works. This is one situation where the Immediate window comes in very handy. This window enables you to run expressions as you type them, as shown below.

To make life easier, the Immediate window supports IntelliSense, and you can use the arrow keys to track back through the history of previous commands executed.

The Immediate window also allows you to execute any Visual Studio command. To submit a command you must enter a greater than symbol > at the start of the line. There is an extremely large set of commands available; in fact almost any action that can be performed within Visual Studio is accessible as a command. Fortunately IntelliSense makes navigating this list of available commands a little more manageable.

Nick blogged last year about aliases, which are available under both the Command and Immediate windows. One of the more well-known aliases is “?”, which is a shortcut for the Debug.Print command that prints out the value of a variable. As long as you have the Immediate window open, this is generally quicker and more convenient than bringing up a watch window, or hovering over a variable and waiting for the data tip to display.

If you start to become really dependant on the Immediate window for your debugging, you should consider enabling the option to Redirect all Output window text to the Immediate window. This option can be enabled under  Tools->Options->Debugging. Although the option says it redirects all Output window text, it will actually only redirect the debug messages (e.g. Debug.Print).