Earlier this year I blogged on how to use the WPF Tree View to view multiple levels. Since then I have had many requests to do the same in WPF. Luckily, the code is almost identical. Here is a blog post on using the WPF Tree View that has multiple levels.
In previous blog posts I have discussed how to use XML files to store data in your applications. I showed you how to read those XML files from your project and get XML from a WCF service. One of the problems with reading XML files is when elements or attributes are missing. If you try to read that missing data, then a null value is returned. This can cause a problem if you are trying to load that data into an object and a null is read. This blog post will show you how to create extension methods to detect null values and return valid values to load into your object.