C# + Revit: Lesson 7 - Global Variables!

Summary

This video tutorial covers the creation and management of global variables in a Revit API add-in project. It introduces the concept of a `Globals` class to store commonly used properties like UI applications and assembly data, making them accessible throughout the project. The video demonstrates how to use Revit's `idling` event to safely retrieve information, such as the `UIApplication`, and explains best practices for organizing code using regions to improve readability. With clear code examples and practical tips, this tutorial helps streamline development and enhances project structure in Revit add-ins.

Takeaways

• 😀 The 'Globals' class stores global properties that need to be accessed throughout the project, such as UI-controlled application, assembly info, version, and username.
• 😀 C# does not have true global variables, but a static class can be used to mimic global variables and provide global access within the project.
• 😀 The 'Idling' event in Revit is used to safely access the 'UIControlledApplication' object once it is available, solving issues where it is not immediately accessible during startup.
• 😀 The 'UIControlledApplication' object is assigned in the 'Idling' event method after Revit has fully initialized, providing access to essential UI elements.
• 😀 The 'Globals' class can also store Revit-specific metadata such as assembly version, add-in version, and Revit version, which can be accessed throughout the project.
• 😀 Using the 'Idling' event ensures that Revit has fully loaded before accessing objects like 'UIControlledApplication', preventing errors in early execution.
• 😀 The 'Globals' class facilitates global access to important project data, allowing consistent management of variables like the Revit username and assembly information.
• 😀 The 'Idling' event is registered in the 'Initialize' method and unsubscribed in the 'Shutdown' method to prevent continuous firing of the event.
• 😀 Code organization is improved with the use of '#region' to group related parts of the code, such as global registration or ribbon setup, making the code more readable and manageable.
• 😀 Using '#region' allows sections of the code to be expanded or collapsed, improving the overall structure and making it easier to focus on relevant parts of the project.

Q & A

What is the purpose of using global variables in a Revit API add-in?

Global variables allow you to store commonly used data such as application-level properties and user-specific details, making them accessible across your entire project. This prevents unnecessary passing of objects and simplifies the workflow.

Why does the script use an idling event in Revit API?

The idling event is used to wait until the Revit application is fully loaded and ready, allowing you to safely access certain objects like `UIControlledApplication` that might not be immediately available after startup.

How does the script handle ambiguity when referencing the `Assembly` class in Revit API?

To avoid ambiguity between the `Assembly` class in Revit API and `System.Reflection.Assembly`, the script explicitly uses the `System.Reflection.Assembly` namespace to ensure the correct class is referenced.

What is the role of the `Globals` class in the provided code?

The `Globals` class is used to store global variables that represent key application-wide data, such as the Revit UI-controlled application, user details, assembly information, and version numbers.

How does the script register the global variables for later use?

The script registers global variables by calling a method within the `Globals` class, which assigns values like the UI-controlled application and user-specific data. This is done during the application's startup phase to ensure that the necessary properties are set up and available.

What is the significance of using `#region` and `#endregion` in the code?

Using `#region` and `#endregion` allows the developer to group sections of the code together, making it easier to collapse and expand parts of the code. This improves code organization, making it cleaner and easier to focus on specific sections of the project.

Why does the tutorial suggest unsubscribing from the idling event after registering the UI application?

Unsubscribing from the idling event after the necessary data has been captured prevents unnecessary event handling, thus conserving system resources and avoiding potential performance issues.

How does the script ensure that the Revit API add-in works for different user environments?

By using global variables to store user-specific details such as the Revit username and Windows username, the script ensures that the add-in works across different user environments, making it adaptable to various setups.

What benefit does the `OnIdling` method provide in terms of code execution?

The `OnIdling` method allows the code to execute when Revit is idle, ensuring that the necessary objects, such as the UI-controlled application, are fully loaded and ready for use before the add-in interacts with them.

How can organizing the code into regions improve collaboration with other developers?

Organizing code into regions makes it easier for multiple developers to work on different parts of the project without confusion. It enhances readability and allows team members to focus on specific sections of the code, improving collaboration and efficiency.