Train Wreck Pattern / Cascade Method Pattern In C#

To figure out the above troubles, we are going to use cascade or train wreck pattern. This improves readability of a code because it avoids repeated references to the instance. So, we can call multiple methods to be called on the same object. This concept was first introduced in Smalltalk programming language.

Here, I have made couple of changes in the code. I have removed all properties, created a couple of methods like Service, Operator etc. and each one returns instance of class itself except DoRecharge() method.
Now we can call DoRecharge method in the following way:
If you look at the above code closely, the beauty of the code is that individual method returns this, so we can invoke each method without making a new line. This is the correct way to use Cascade pattern or method cascading. This pattern is a very useful if object has a very lengthy expression value because it removes the need of using temporary variable or need to either list the expression repeatedly

So, using such pattern we can remove verbosity from code. Now, after looking at the above code, some of you might be thinking that we have been writing such code a million times particularly when we are writing LINQ query.
That’s absolutely right. This pattern particularly applied in fluent interfaces. An interface is said to be fluent if it returns itself from one or more its method. This allow users to chain calls together. A fluent interface is an implementation of an object oriented API that aims to provide more readable code. All the LINQ queries including above and others use this concept.

We can also achieve the same thing using lambda: