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Clean Coding in Xojo: Best Practices for Writing Maintainable Code

Clean coding is a vital aspect of software development that ensures code readability, maintainability, and scalability. In the context of Xojo, adhering to clean coding principles can significantly enhance the quality and longevity of your projects. In this blog post, we’ll explore key practices for clean coding in Xojo, including the advantages and disadvantages of these approaches, with detailed examples and explanations.

Why Clean Coding Matters

Before diving into the specific practices, it’s important to understand why clean coding matters:

1. Readability: Clean code is easier to read and understand, which is crucial when multiple developers are involved or when you revisit your code after some time. This reduces the cognitive load on developers, making it easier to grasp the code’s functionality quickly.

2. Maintainability: Code that follows clean coding principles is easier to maintain and update, reducing the risk of introducing bugs. Maintainable code allows for efficient troubleshooting and quick implementation of changes or new features.

3. Scalability: Clean code can be more easily extended with new features, facilitating the growth of your application. Well-structured code makes it easier to see where and how new functionality can be added without disrupting existing features.

Key Practices for Clean Coding in Xojo

1. Use Meaningful Names

Using meaningful and descriptive names for variables, methods, and classes is one of the simplest yet most powerful practices in clean coding. Avoid abbreviations and opt for clear, self-explanatory names. This practice helps other developers understand your code without needing extensive documentation.


// Bad
Var n As Integer
// Good
Var userCount As Integer

In the good example, userCount clearly indicates the purpose of the variable, making the code easier to understand at a glance.

2. Follow Consistent Coding and Naming Conventions

Consistent naming conventions make your codebase uniform and easier to navigate. Establish and follow conventions for variables, methods, properties, and classes.

Read more detailed about Coding and Naming Conventions in the Xojo Documentation

3. Keep Methods Short and Focused

Each method should perform a single, well-defined task. If a method is too long or performs multiple tasks, consider refactoring it into smaller, more focused methods. This makes the code more modular and easier to test and maintain.


// Bad
Sub ProcessUserData()
  ' Code to validate user input
  ' Code to save user data to the database
  ' Code to send a confirmation email
End Sub
// Good
Sub ProcessUserData()
End Sub

Sub ValidateUserInput()
  ' Validation logic
End Sub

Sub SaveUserData()
  ' Database saving logic
End Sub

Sub SendConfirmationEmail()
  ' Email sending logic
End Sub

By breaking down ProcessUserData into smaller methods, each method has a single responsibility, which makes the code easier to understand and maintain.

4. Comment Wisely

Comments should explain why something is done, not what is done. The code itself should be self-explanatory whenever possible. Over-commenting can clutter the code, while under-commenting can make it difficult to understand the rationale behind certain decisions.


// Bad
// Increment the user count by 1
userCount = userCount + 1
// Good
// Increment the user count to keep track of active users
userCount = userCount + 1

In the good example, the comment provides context for why the increment is necessary, which might not be immediately obvious from the code alone.

5. Use Constants and Enumerations

Avoid using magic numbers and strings. Instead, define constants and enumerations for values that have specific meanings. This makes your code more readable and easier to update.


// Bad
If statusCode = 200 Then
  ' Success logic
End If
// Good
Const kHTTP_SUCCESS As Integer = 200
If statusCode = kHTTP_SUCCESS Then
  ' Success logic
End If

Using kHTTP_SUCCESS instead of 200 makes the code more readable and the purpose of the value clearer.


Enumerations (enums) are a powerful way to represent a set of related constants. They make your code more readable and maintainable by grouping related values under a single type. This can be particularly useful for handling states, options, or categories in your application.


// Define an enumeration for user roles
Enum UserRole
End Enum

// Use the enumeration
Var currentUserRole As UserRole = UserRole.Admin

Select Case currentUserRole
Case UserRole.Admin
  ' Admin-specific logic
Case UserRole.Editor
  ' Editor-specific logic
Case UserRole.Viewer
  ' Viewer-specific logic
End Select

In this example, the UserRole enum defines three possible roles: Admin, Editor, and Viewer. Using an enum makes the code more readable and ensures that only valid roles are assigned to currentUserRole.

6. Handle Errors Gracefully

Implement proper error handling to ensure your application can gracefully recover from unexpected conditions. Use Try…Catch blocks and meaningful error messages. This practice improves the robustness and user experience of your application.


  ' Code that might throw an exception
Catch e As OutOfBoundsException
  // Log the error and inform the user
  System.DebugLog("Error: " + e.Message)
  MessageBox("An unexpected error occurred.")
End Try

By catching exceptions and providing informative error messages, you help users understand what went wrong and how to proceed, while also aiding in debugging and logging.

7. Refactor Regularly

Refactoring is the process of improving the structure of your code without changing its functionality. Regular refactoring helps keep your code clean and manageable. It involves restructuring your code to improve its internal structure while maintaining its external behavior.


Before refactoring:

Sub DoEverything()
  ' Lots of code here
End Sub

After refactoring:

Sub DoEverything()
End Sub

Sub PerformTaskA()
  ' Task A code
End Sub

Sub PerformTaskB()
  ' Task B code
End Sub

Sub PerformTaskC()
  ' Task C code
End Sub

By breaking down DoEverything into smaller tasks, the code becomes more modular and easier to maintain.

Advantages and Disadvantages of Clean Coding


  1. Improved Readability: Clean code is easier for other developers and yourself to read and understand, which is crucial for effective collaboration and maintenance.
  2. Easier Maintenance: Maintenance tasks are simplified with well- structured and well-documented code, reducing the time and effort required to update and debug the code.
  3. Fewer Bugs: Following clean coding principles reduces the risk of bugs by promoting clarity and simplicity in the code.
  4. Better Collaboration: Teams can work more efficiently together when the code is understandable and consistent, reducing misunderstandings and errors.
  5. Scalability: It’s easier to integrate new features when the code is well- structured, as the modular design allows for more straightforward extensions.


  1. Time Investment: Clean coding requires more time and effort, especially in naming, documentation, and refactoring. This can slow down initial development but pays off in the long run.
  2. Initial Learning Curve: Developers unfamiliar with clean coding principles need time to learn and apply them, which can temporarily decrease productivity.
  3. Over-Perfection: There’s a risk of spending too much time perfecting the code, which can impact overall productivity and delay project timelines.

Clean coding is not just a set of guidelines but a mindset that can significantly improve the quality of your software. By adopting clean coding practices in Xojo, you ensure that your codebase remains readable, maintainable, and scalable. Whether you are working on a small project or a large application, these principles will help you write better code and build more robust software.

Incorporating clean coding practices into your development workflow might require an initial investment of time and effort, but the benefits far outweigh the costs. Clean code leads to fewer bugs, easier maintenance, and a codebase that can grow and evolve with your project’s needs.

Happy coding!

Martin T. is a Xojo MVP and has been very involved in testing Android support.