Often, I've found myself writing code to display or format lists, collections, or arrays. Most frequently, this is as simple as displaying a comma separated list, for example: item-1, item-2, item-3. Occasionally, the requirements are a bit more complex. This article describes a class (EnumerableExt) that can reduce the complexity of this task. The class is implemented as a set of extension methods (Append, BuildString, Write) to the IEnumerable interface.