Adding Dynamic Properties: ExpandoObject vs DynamicObject

TL;DR

This video demonstrates how to use dynamic objects (specifically, ExpandoObject and a custom DynamicObject) in C# to build and manipulate objects with dynamic properties, and showcases their application in parsing CSV files to JSON.

Transcript

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Key Insights

• 🔬 Dynamic properties in C#: The content discusses the struggle of working with dynamic properties in C# and how it is easy in JavaScript.
• 🔧 Expando Object: Expando object is a flexible and dynamic way to create objects with dynamic properties in C#. It provides an easy way to add properties and methods at runtime.
• 💡 Limitations of Expando Object: Expando object can crash if we try to access properties that have not been defined yet. To avoid this, it is recommended to cast the object as an IDictionary and then dynamically add properties.
• 🔀 Dynamic Object: Dynamic object is a base class in C# that allows us to create our own dynamic objects. By implementing IDictionary and overriding try get member and try set member methods, we can define our own dynamic behavior.
• 🛠️ Custom API with Dynamic Object: Using dynamic object allows us to create custom methods like add property, making the API more intuitive and useful.
• 💻 Example of Dynamic Object: The content demonstrates how to parse a CSV file and convert it into JSON using dynamic object, showing the practical application of working with dynamic properties.
• 😕 Issue with Dynamic Object: When using dynamic object, we need to handle serialization manually by creating a custom JSON converter, but it provides more control and flexibility in handling dynamic scenarios.

Questions & Answers

Q: How can dynamic objects be used to handle scenarios with properties that are unknown until runtime?

Dynamic objects, such as ExpandoObject and custom DynamicObject, can be used to handle scenarios with unknown property names and values at runtime. By using these objects, properties can be added dynamically, and methods can be added to the objects as well. This allows for the creation of objects that can be customized based on the specific requirements of the application or scenario.

Q: What are the limitations of using ExpandoObject for working with dynamic properties in C#?

While ExpandoObject provides flexibility for creating dynamic objects and adding properties at runtime, it has some limitations. One limitation is that if you try to read an object property that hasn't been defined, it will result in a runtime exception. Additionally, ExpandoObject does not provide a simple way to handle scenarios where property names and values are unknown, which can make it less suitable for certain dynamic scenarios.

Q: How can a custom DynamicObject be created in C#?

To create a custom DynamicObject in C#, a new class can be derived from the DynamicObject base class. This allows for custom implementation of methods that control how the dynamic object behaves. By overriding methods like TryGetMember and TrySetMember, the custom DynamicObject can handle dynamic operations, such as getting and setting property values, in a customized way.

Q: What advantages does a custom DynamicObject offer over ExpandoObject?

A custom DynamicObject provides more control and flexibility compared to ExpandoObject. With a custom DynamicObject, you can define your own methods and create a more tailored API for working with dynamic properties. Additionally, it allows for handling scenarios where property names and values are unknown, making it more suitable for complex dynamic scenarios, such as parsing CSV files.

Summary & Key Takeaways

• The video discusses the use of dynamic objects, specifically ExpandoObject and a custom DynamicObject, in C# for creating and manipulating objects with dynamic properties.

• The speaker demonstrates the limitations of using ExpandoObject and provides an alternative approach using a custom DynamicObject.

• The video showcases a real-world example of parsing a CSV file and converting it into a collection of dynamic objects, which are then serialized into JSON.

• The custom DynamicObject provides more flexibility and allows for the creation of a simpler API for handling dynamic scenarios.