How to Display a List Property in a Nested Object in C# MAUI

Learn how to effectively display a `List` property from a nested object in your MAUI application using MVVM pattern. This guide includes step-by-step instructions and code snippets to resolve common binding errors.
---

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: How to display List property In nested object c# MAUI

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Display a List Property in a Nested Object in C# MAUI

Building applications in .NET MAUI (Multi-platform App UI) with MVVM (Model-View-ViewModel) architecture can sometimes lead to binding errors, especially when dealing with nested objects. One common issue developers face is displaying properties from a list within nested objects in the UI.

In this guide, we will explore how to correctly bind a property from a list in a nested object using C# . We'll address an example scenario and walk through the solution to help you troubleshoot similar binding issues in your own MAUI applications.

The Problem

You are building an application in MAUI C# , and you've structured your View, ViewModel, and Model as follows:

View: Contains a CollectionView intended to display items from a list property.

ViewModel: Contains an instance of the TestModel, which includes the list property.

Model: Defines the structure of nested objects, including a List<Toto>, which has the property Plop that you want to display.

However, you encounter an error stating that the property "Plop" could not be found, even though it exists in the Toto model.

The Binding Error

The error message indicates that the binding is attempting to find the Plop property on the TestViewModel, which does not contain any such property. To resolve this, you need to ensure that the CollectionView is properly set up to recognize items of type Toto.

The Solution

Here’s how to fix the binding error and successfully display the Plop property:

Step 1: Add XML Namespace for Models

First, you'll need to introduce an XML namespace (xmlns) for your model classes in your XAML file. This allows the XAML parser to recognize the Toto type.

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

Step 2: Specify Data Type in DataTemplate

Next, you need to tell the CollectionView about the data type it will be working with. Modify your DataTemplate to specify that it draws from the Toto class.

Change your DataTemplate declaration to include the x:DataType property:

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

Updated XAML Example

After applying the suggested changes, your XAML should look like this:

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

Step 3: Check Your ViewModel and Model

Make sure your ViewModel and Models are set up properly, as they are crucial for the data-binding process. If the API call correctly populates the Toto list within TestModel, then your UI should display the Plop property without errors.

Final Thoughts

By following the steps outlined above, you should be able to resolve the binding error and display properties from nested objects seamlessly. This approach will enhance your ability to work with complex data structures in C# MAUI while adhering to the MVVM design pattern.

If you have questions or run into issues during implementation, feel free to leave a comment below! Happy coding!