Resolving JSON.NET Deserialization Issues for Complex Classes in C#

Learn how to effectively deserialize complex JSON objects in C# using JSON.NET by handling lists of nested classes accurately.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: JSON.NET deserialization of class containing a list of classes

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Resolving JSON.NET Deserialization Issues for Complex Classes in C#

Deserializing JSON into complex objects in C# using JSON.NET can sometimes lead to unexpected behaviors, especially when dealing with nested classes or lists. One common issue developers encounter is when desired properties return unexpected default values, like 0 for numeric types. This guide will break down the problem you've faced, specifically with a class called MyDoc that contains lists of MyLine and MyPolyline classes. We will explore how to fix the deserialization issue with your MyPoint2d and MyPolyline classes.

The Problem

Suppose you have a class structure designed to represent geometric shapes (lines and polylines) that utilize AutoCad's Point2d class. Upon deserializing the JSON into your MyDoc object, you observe that while the MyLine entities seem to deserialize correctly, the points within the MyPolyline are returning default values (0) for their X and Y coordinates. This indicates that something is off in how properties in your classes are mapped to the JSON structure.

The JSON structure you are dealing with looks something like this:

[[See Video to Reveal this Text or Code Snippet]]

Analyzing the deserialization issue

The problem arises because the MyPoint2d class is not being populated correctly during deserialization. The fields might not align with the expected JSON structure due to missing or incorrectly defined JsonProperty attributes.

The Solution

The solution involves ensuring that the property names in your classes correspond accurately to the structure of your JSON. You can streamline your classes by removing the explicit JsonProperty attributes when the property names are identical to the JSON keys. Here’s how to modify your classes:

Updated Class Definitions

MyPoint2d Class:

Keep the properties X and Y as they are without the need for [JsonProperty] attributes since they match the JSON keys.

[[See Video to Reveal this Text or Code Snippet]]

MyPolyline Class:

Ensure the list of points directly corresponds to the JSON by keeping the property name as Points.

[[See Video to Reveal this Text or Code Snippet]]

MyLine Class:

Similar to MyPolyline, make sure the properties are appropriately aligned.

[[See Video to Reveal this Text or Code Snippet]]

MyDoc Class:

Ensure the collections for lines and polylines are correctly defined.

[[See Video to Reveal this Text or Code Snippet]]

Deserialization Code

After you have adjusted your class definitions, you can deserialize your JSON file content as follows:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By aligning your class definitions with the JSON structure and ensuring the property names map correctly, you can facilitate a smoother deserialization process with JSON.NET. Removing unnecessary JsonProperty attributes when property names match the JSON keys simplifies your classes and can help avoid issues like those inadvertently causing the deserialized points to register as zero.

Now that you have a clearer understanding of the deserialization process for complex classes, you should find it easier to handle similar issues in the future. Happy coding!