👀 Views: 0 💬 Answers: 1 📅 Created: 2025-06-13

blazor .net6 httpclient exception-handling csharp

I've been working on this all day and I'm experiencing an intermittent `NullReferenceException` in a Blazor component that seems to occur during state management..... The scenario arises when I try to access a property of a model that is supposed to be populated after an async call to an API. Sometimes, the property is null, and my application crashes with the following stack trace: ``` NullReferenceException: Object reference not set to an instance of an object. at MyApp.Pages.MyComponent.OnInitializedAsync() in MyComponent.razor.cs:line 30 at Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync() ``` In my `OnInitializedAsync` method, I’m fetching data from an API and setting the component's state: ```csharp protected override async Task OnInitializedAsync() { var response = await HttpClient.GetAsync("/api/mydata"); if (response.IsSuccessStatusCode) { var data = await response.Content.ReadFromJsonAsync<MyDataModel>(); // Possible NullReferenceException when accessing data.Property MyProperty = data.Property; } } ``` I've checked the API response, and it appears to be valid JSON with all expected fields. However, during some page loads, `data` is null, which leads to the exception. I've added null checks, like so: ```csharp if (data != null) { MyProperty = data.Property; } else { // Log or handle the behavior } ``` Yet, the question continues intermittently. I've also ensured that the HTTP client is correctly injected and initialized in the program. Has anyone encountered this scenario or can suggest additional debugging steps to diagnose why the `data` object is sometimes null? Is there a best practice for handling API responses in Blazor when dealing with potential transient failures? This is happening in both development and production on Windows 11. I'm using Csharp latest in this project. I'd really appreciate any guidance on this. The stack includes Csharp and several other technologies. Cheers for any assistance!