Here is code that will allow you to decorate your MVC Actions with attributes that will define your needed "preconditions". I often find the need to check for the existence of a parameter passed to a web page, such as an ID, and also often need to check if the ID is valid as well (e.g.: a valid primary key). These, I consider "preconditions".

Free reusable generic Directory Poller utility class for .NET (especially useful when FileSystemWatcher is insufficent).

You may not realize that System.IO.File.Move() doesn't support overwriting of an existing file. In fact, it will throw an IOException if a file with the same path as sourceDestFilename already exists. Here is a wrapper method that does...

Example of how to overload operators in C#

Attain concise, highly-readable Ruby-like date syntax with C# 3.0 Extension Methods and Fluent Interface design.

Example code illustrating how to build a Fluent Interface in C#.

Instead of using a different Assert method for each different type of assertion (e.g.: Assert.AreEqual() for equality comparison, or Assert.IsTrue() for boolean evaluation), the new Constraint-Based Assert Model introduced in NUnit 2.4 utilizes only one Assert method named Assert.That().

Six Free Custom .NET String Manipulation Functions / Methods for Everyday Use

Depending on your math background, .NET's rounding functionality may not work the way you expect! Check out the included code to implement an alternative (known as Common Rounding) in addition to .NET's built-in Math.Round() function.

This is the C# code for an ASP.NET required validator web control that requires a specified set of controls to be all populated, or all empty. It inherits from the RequiredFieldValidator ASP.NET class, so it essentially works the same way, it just treats the set of controls you specify as if they were one control (in the sense of requirement).