Mastering Code Metrics in Visual Studio: A Comprehensive Guide for C# Developers

Code quality is the foundation of any successful software project. Without consistent quality, applications become harder to maintain, more prone to bugs, and less efficient over time. This is where code metrics come into play. By providing measurable insights into your code’s structure, complexity, and maintainability, code metrics serve as a compass to guide developers toward cleaner, more efficient codebases.

Visual Studio makes analyzing code quality straightforward with its built-in code metrics tool. Whether you’re working on a small project or managing an enterprise-level application, understanding and applying these metrics can significantly enhance your development process. In this blog, we’ll delve into the essentials of code metrics, their importance, and how to use them effectively in Visual Studio to improve your code quality and maintainability.

What Are Code Metrics?

Code Metrics are quantitative measurements that provide insights into the quality and maintainability of your codebase. They help identify areas of potential improvement by measuring various attributes such as cyclomatic complexity, maintainability index, and inheritance depth. Visual Studio includes a built-in Code Metrics tool to assist developers in analyzing and improving their code.

Some of the key metrics measured include:

1. Maintainability Index
2. Cyclomatic Complexity
3. Depth of Inheritance
4. Class Coupling
5. Lines of Code (LOC)

Let’s break these down one by one with practical code examples.

How to Calculate Code Metrices in Visual Studio

• Navigate to the Analyze menu in the top toolbar.

1. Maintainability Index

The Maintainability Index is a measure of how maintainable the code is. It is calculated based on factors like cyclomatic complexity, lines of code, and code density. The maintainability index is expressed as a value between 0 and 100:

• 0–19: Poor maintainability (difficult to maintain)
• 20–39: Moderate maintainability
• 40–100: High maintainability

Here is an example of poorly maintainable code:

public static double Calculate(int x, int y, CalculationType type)
{
    double result = 0;

    // Deeply nested conditional statements
    if (type == CalculationType.Add)
    {
        if (x > 0)
        {
            if (y > 0)
            {
                result = x + y;
            }
            else
            {
                result = x - Math.Abs(y);
            }
        }
        else
        {
            if (y > 0)
            {
                result = Math.Abs(x) + y;
            }
            else
            {
                result = -Math.Abs(x + y);
            }
        }
    }
    else if (type == CalculationType.Subtract)
    {
        if (x > y)
        {
            result = x - y;
        }
        else
        {
            result = y - x;
        }
    }
    else if (type == CalculationType.Multiply)
    {
        result = 0;
        for (int i = 0; i < Math.Abs(y); i++)
        {
            result += x;
        }
        if (y < 0)
        {
            result = -result;
        }
    }
    else if (type == CalculationType.Divide)
    {
        if (y == 0)
        {
            throw new DivideByZeroException("Cannot divide by zero");
        }
        result = x / y;
    }
    else
    {
        throw new ArgumentException("Invalid calculation type");
    }

    // Redundant loop to increase complexity
    for (int i = 0; i < 100; i++)
    {
        result += i;
    }

    return result;
}

Now let’s calculate the code metrices for the above code.

Although the Maintainability Index for the above method is 48, which does not fall under the ‘Poor Maintainability’ category, we can further improve this code to achieve a higher index.

 public static double Calculate(int x, int y, CalculationType type)
 {
     return type switch
     {
         CalculationType.Add => x + y,
         CalculationType.Subtract => x - y,
         CalculationType.Multiply => x * y,
         CalculationType.Divide => x / y,
         _ => throw new ArgumentException("invalid calculation type")
     };
 }

Let’s again calculate the code metrices for the improved method:

As you can see, the Maintainability Index has now increased to 86, indicating that the code’s maintainability is very high.

2. Cyclomatic Complexity

Cyclomatic Complexity measures the number of independent paths through a function or method. The more branching and decision-making statements (e.g., if, switch, for, etc.) in a function, the higher its cyclomatic complexity.

Consider the below code to demonstrate Cyclomatic Complexity Index:

public void ProcessData(int value)
{
    if (value > 0)
    {
        if (value < 10)
        {
            Console.WriteLine("Value is between 1 and 9.");
        }
        else if (value < 20)
        {
            Console.WriteLine("Value is between 10 and 19.");
        }
        else
        {
            Console.WriteLine("Value is 20 or more.");
        }
    }
    else
    {
        Console.WriteLine("Value is 0 or negative.");
    }
}

Let’s calculate the code metrices for the above method:

In this method, multiple nested if-else statements increase the cyclomatic complexity, making the code harder to manage. Let’s refactor the method as below and re-calculate the code metrices.

public void ProcessData(int value)
{
    string message = value switch
    {
        < 0 => "Value is 0 or negative.",
        < 10 => "Value is between 1 and 9.",
        < 20 => "Value is between 10 and 19.",
        _ => "Value is 20 or more."
    };

    Console.WriteLine(message);
}

By utilizing a switch expression, the refactored method reduces cyclomatic complexity, enhancing readability and maintainability.

3. Depth of Inheritance

The Depth of Inheritance quantifies the maximum number of successive parent classes a given class inherits from, starting from the root of the hierarchy. In object-oriented design, Depth of Inheritance is a crucial metric that reflects both the complexity and potential reusability of code.

class Animal
{

}

class Pet : Animal
{
}

class Cat : Pet
{

}

In this example, the Cat class has an inheritance depth of 2. Understanding and monitoring the Depth of Inheritance in your codebase can help maintain a balance between leveraging inheritance for code reuse and managing complexity for maintainability.

4. Class Coupling

Class Coupling, also known as Coupling Between Objects (CBO), is a crucial metric in Visual Studio’s code analysis toolkit. It quantifies the number of unique classes that a single class depends upon, providing insight into the interdependencies within your codebase.

• Maintainability: High class coupling indicates a design with numerous interdependencies, making the code more challenging to maintain and modify. Changes in one class can have cascading effects on others, increasing the risk of introducing defects.
• Reusability: Classes with lower coupling are more modular and easier to reuse across different projects or modules, as they have fewer external dependencies.

class Cat 
{
    public Color Color { get; set; } = new();
    public Breed Breed { get; set; } = new();
}

class Color
{
    public string General { get; set; } = string.Empty;
    public string? Body { get; set; }
    public string? Face { get; set; }
    public string? Legs { get; set; }
    public string? Tail { get; set; }
 
}

class Breed
{
    public string CommonName { get; set; } = string.Empty;
    public string? Description { get; set; }
}

Here, the Cat class is coupled with Color and Breed. To reduce coupling, interfaces can be introduced.

5. Lines of Code (LOC)

Lines of Code (LOC) is a measure of the size of a method or class.

Types of LOC Metrics:

1. Lines of Source Code: This metric counts all lines in the source files, including blank lines, comments, and code. It offers a general overview of the project’s size.
2. Lines of Executable Code: This metric counts only the lines that contain executable statements, excluding comments and whitespace. It provides a more accurate representation of the code that contributes to the application’s functionality.

Best Practices:

• Maintain Readability: While LOC is a useful indicator, it’s essential to balance code length with readability. Ensure that methods and classes are concise but not at the expense of clarity.
• Refactor Large Methods: Large methods can be challenging to maintain and understand. Consider breaking them into smaller, more manageable functions to enhance readability and reduce complexity.
• Use LOC in Context: LOC should be considered alongside other metrics, such as Cyclomatic Complexity and Maintainability Index, to gain a comprehensive understanding of code quality.

Visual Studio’s Code Metrics feature is an invaluable tool for improving the quality and maintainability of your codebase. By regularly analyzing metrics like the Maintainability Index, Cyclomatic Complexity, and Class Coupling, you can identify problem areas, reduce technical debt, and create more efficient, maintainable software.

Incorporate code metrics analysis into your workflow and leverage these insights to build better, cleaner, and more maintainable applications.

See you in the next post. Happy coding!