Difficulty with Custom Model Binding in ASP.NET Core 6 for Complex Types
I'm experimenting with I'm maintaining legacy code that I'm stuck on something that should probably be simple. I'm sure I'm missing something obvious here, but I'm working with an scenario with custom model binding in an ASP.NET Core 6 application. I have a complex type that consists of several nested objects, and I want to implement a custom model binder for it. However, I'm getting a `400 Bad Request` response when trying to bind the model. Here's a simplified version of my model: ```csharp public class Order { public int OrderId { get; set; } public Customer Customer { get; set; } } public class Customer { public string Name { get; set; } public Address ShippingAddress { get; set; } } public class Address { public string Street { get; set; } public string City { get; set; } } ``` I've implemented a custom model binder like this: ```csharp public class OrderModelBinder : IModelBinder { public async Task BindModelAsync(ModelBindingContext bindingContext) { // Binding logic here // Binding the Order object and its nested properties } } ``` In the controller, I'm trying to use the binder as follows: ```csharp [HttpPost] public async Task<IActionResult> CreateOrder([ModelBinder(BinderType = typeof(OrderModelBinder))] Order order) { // Process order } ``` When I post the JSON object like this: ```json { "OrderId": 1, "Customer": { "Name": "John Doe", "ShippingAddress": { "Street": "123 Elm St", "City": "Somewhere" } } } ``` I get a `400 Bad Request` behavior without any clear indication of what went wrong. I've tried debugging the `BindModelAsync` method, but it seems like the binding context isn't even hitting my custom binder. I've ensured that the model binder is registered in the `Startup.cs`: ```csharp services.AddControllers(options => { options.ModelBinderProviders.Insert(0, new OrderModelBinderProvider()); }); ``` Could there be something I'm missing in my setup, or is there a specific way to format the JSON that the model binder expects? Any insights on how to resolve this would be greatly appreciated. This is part of a larger web app I'm building. What am I doing wrong? This issue appeared after updating to C# LTS. Could someone point me to the right documentation? I'm working in a Linux environment. Thanks in advance! My team is using C# for this service. Thanks in advance!