ASP.NET Core MVC: ModelState Not Validating Nested Models Correctly
I'm prototyping a solution and I'm reviewing some code and I've been banging my head against this for hours. Hey everyone, I'm running into an issue that's driving me crazy. I'm working with an scenario with model validation in my ASP.NET Core MVC application. I have a parent model that contains a nested model, and when I submit the form, the `ModelState.IsValid` always returns false, but I need to figure out why. Here's the structure of my models: ```csharp public class ParentModel { public string Name { get; set; } public ChildModel Child { get; set; } } public class ChildModel { [Required] public string Age { get; set; } } ``` And in my view, I am using a form that looks something like this: ```html <form asp-action="Submit"> <input asp-for="Name" /> <input asp-for="Child.Age" /> <button type="submit">Submit</button> </form> ``` When I submit the form without entering any values, I expect to see validation errors. However, the errors don't seem to bind properly to the child model. I have tried adding the `[Bind]` attribute to the action method to ensure the nested model gets bound, like this: ```csharp [HttpPost] public IActionResult Submit([Bind(nameof(ParentModel.Name), nameof(ParentModel.Child))] ParentModel model) { if (!ModelState.IsValid) { // Log ModelState errors return View(model); } // Process the valid model return RedirectToAction("Success"); } ``` Despite these changes, the `ModelState` still doesn't indicate which specific part of the model is invalid. I also checked the generated HTML and the names appear correct: `Name` for the parent and `Child.Age` for the child model. Could this be related to how nested models are being validated in ASP.NET Core 5.0? Any insights or suggestions on how to properly validate nested models in this scenario would be greatly appreciated! For context: I'm using Csharp on Linux. Thanks in advance! Thanks in advance! I'm on macOS using the latest version of Csharp. Any examples would be super helpful. I'm on Ubuntu 22.04 using the latest version of Csharp.