Default Warning levels for Code Analysis

If you have not used Code Analysis tools in Visual Studio 2012, you are missing out on tools that would help you write a better code.  If you run code analysis on your solution, you will be given a report that analyses the following metrics in your code.

Maintainability Index – Calculates an index value between 0 and 100 that represents the relative ease of maintaining the code. A high value means better maintainability. The calculation is based on the Halstead Volume, Cyclomatic Complexity and Lines of Code. Color coded ratings can be used to quickly identify trouble spots in your code. A green rating is between 20 and 100 and indicates that the code has good maintainability. A yellow rating is between 10 and 19 and indicates that the code is moderately maintainable. A red rating is a rating between 0 and 9 and indicates low maintainability.

Cyclomatic Complexity – Measures the structural complexity of the code. It is created by calculating the number of different code paths in the flow of the program such as if blocks, switch cases, and do, while, foreach and for loops then adding 1 to the total. A program that has complex control flow will require more unit tests to achieve good code coverage and will be less maintainable.

Depth of Inheritance – Indicates the number of class definitions that extend to the root of the class hierarchy. The deeper the hierarchy the more difficult it might be to understand where particular methods and fields are defined or/and redefined. At the class level the number is created by calculating the number of types that are above the type in the inheritance tree starting from 0 and excludes interfaces. At the namespace and project level the calculation consists of the highest Depth of Inheritance calculation of all of the types within the namespace or project.

Class Coupling – Measures the coupling to unique classes through parameters, local variables, return types, method calls, generic or template instantiations, base classes, interface implementations, fields that are defined on external types, and attribute decoration. The calculation excludes primitive and built-in types such as int32, string and object. Good software design dictates that types and methods should have high cohesion and low coupling. High coupling indicates a design that is difficult to reuse and maintain because of its many interdependencies on other types.

Lines of Code – Indicates the approximate number of lines in the code. The count is based on the IL code and is therefore not the exact number of lines in the source code file. The calculation excludes white space, comments, braces and the declarations of members, types and namespaces. A very high count might indicate that a type or method is trying to do too much work and should be split up. It might also indicate that the type or method might be difficult to maintain.

If you are wondering what values trigger warnings, here are warning values for the measurements:

Depth of Inheritance: Threshold: Warning at above 5 levels deep
Cyclomatic Complexity: Threshold: Warning at above 25
Maintainability Index: Threshold: Warning at below 20
Class Coupling: Threshold: Warning at above 80 for class and above 30 for a method

Here is how Maintainability index is computed.

All this information is taken from MSDN.  Read more by following these links:


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