InvalidOperationException: EditForm requires either a Model parameter, or an EditContext parameter ... - Caused by Using a Poco in different assembly that has public fields instead of auto-properties

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All,

SSR page with EditForm. The EditForm binds to a Model (of type to a type ClientSearchCriteria2) which is a type defined in another assembly referenced by the project, I get the following run-time exception below. The Exception is caused because the Model class has only public fields, instead of properties.

1. Why is binding to public fields not supported? We have simple pocos with public fields
2. The exception is totally misleading. Fix the exception message to be more context specific.

Code

<EditForm Enhance Model="ClientCriteria" OnValidSubmit="OnClientSearchAsync" FormName="client-search-form">

[SupplyParameterFromForm(FormName = "client-search-form")] public ClientSearchCriteria2 ClientCriteria { get; set; } = new();

ClientSearchCriteria2 is a poco with public fields (NOT using properties).

The Exception, that is misleading:

InvalidOperationException: EditForm requires either a Model parameter, or an EditContext parameter, please provide one of these.
Microsoft.AspNetCore.Components.Forms.EditForm.OnParametersSet()
Microsoft.AspNetCore.Components.ComponentBase.CallOnParametersSetAsync()
Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()
Microsoft.AspNetCore.Components.HtmlRendering.Infrastructure.StaticHtmlRenderer.HandleException(Exception exception)
Microsoft.AspNetCore.Components.RenderTree.Renderer.HandleExceptionViaErrorBoundary(Exception error, ComponentState errorSourceOrNull)
Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToPendingTasksWithErrorHandling(Task task, ComponentState owningComponentState)
Microsoft.AspNetCore.Components.Rendering.ComponentState.SupplyCombinedParameters(ParameterView directAndCascadingParameters)
Microsoft.AspNetCore.Components.Rendering.ComponentState.SetDirectParameters(ParameterView parameters)
Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InitializeNewComponentFrame(ref DiffContext diffContext, int frameIndex)
Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InitializeNewSubtree(ref DiffContext diffContext, int frameIndex)
Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InsertNewFrame(ref DiffContext diffContext, int newFrameIndex)
Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForRange(ref DiffContext diffContext, int oldStartIndex, int oldEndIndexExcl, int newStartIndex, int newEndIndexExcl)
Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.ComputeDiff(Renderer renderer, RenderBatchBuilder batchBuilder, int componentId, ArrayRange oldTree, ArrayRange newTree)
Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, out Exception renderFragmentException)
Microsoft.AspNetCore.Components.RenderTree.Renderer.RenderInExistingBatch(RenderQueueEntry renderQueueEntry)
Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()
Microsoft.AspNetCore.Components.HtmlRendering.Infrastructure.StaticHtmlRenderer.HandleException(Exception exception)
Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()
Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessPendingRender()
Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToRenderQueue(int componentId, RenderFragment renderFragment)
Microsoft.AspNetCore.Components.RenderHandle.Render(RenderFragment renderFragment)
Microsoft.AspNetCore.Components.ComponentBase.StateHasChanged()
Microsoft.AspNetCore.Components.ComponentBase.CallOnParametersSetAsync()
Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()
Microsoft.AspNetCore.Components.HtmlRendering.Infrastructure.StaticHtmlRenderer.HandleException(Exception exception)
Microsoft.AspNetCore.Components.RenderTree.Renderer.HandleExceptionViaErrorBoundary(Exception error, ComponentState errorSourceOrNull)
Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToPendingTasksWithErrorHandling(Task task, ComponentState owningComponentState)
Microsoft.AspNetCore.Components.Rendering.ComponentState.SupplyCombinedParameters(ParameterView directAndCascadingParameters)
Microsoft.AspNetCore.Components.Rendering.ComponentState.SetDirectParameters(ParameterView parameters)
Microsoft.AspNetCore.Components.RenderTree.Renderer.RenderRootComponentAsync(int componentId, ParameterView initialParameters)
Microsoft.AspNetCore.Components.HtmlRendering.Infrastructure.StaticHtmlRenderer.BeginRenderingComponent(IComponent component, ParameterView initialParameters)
Microsoft.AspNetCore.Components.HtmlRendering.Infrastructure.StaticHtmlRenderer.BeginRenderingComponent(Type componentType, ParameterView initialParameters)
Microsoft.AspNetCore.Components.Endpoints.EndpointHtmlRenderer.RenderEndpointComponent(HttpContext httpContext, Type rootComponentType, ParameterView parameters, bool waitForQuiescence)
System.Threading.Tasks.ValueTask.get_Result()
Microsoft.AspNetCore.Components.Endpoints.RazorComponentEndpointInvoker.RenderComponentCore(HttpContext context)
Microsoft.AspNetCore.Components.Endpoints.RazorComponentEndpointInvoker.RenderComponentCore(HttpContext context)
Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContext+<>c+<b__10_0>d.MoveNext()
Microsoft.AspNetCore.Localization.RequestLocalizationMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Antiforgery.Internal.AntiforgeryMiddleware.InvokeAwaited(HttpContext context)
Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.SystemWebAdapters.PreBufferRequestStreamMiddleware.InvokeAsync(HttpContext context)
Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

Describe the solution you'd like

See description.

Additional context

No response

[javiercn]

@htmlsplash thanks for contacting us.

It's very likely that there is an error submitting your form and since you are initializing it in the property initializer it's being set to null after binding. The correct way to initialize form fields is to do so inside OnInitialized(Async). For example:

protected override void OnInitialized() => ClientCriteria ??= new();

[htmlsplash]

@javiercn Okay, that fixed the null reference issue (although, the error message really doesn't help correct the problem especially since in lots of samples for interactive server pages initializes the field/property inline like in my case).
Just FYI: The null reference exception also goes away when I use Poco with auto properties with the code I posted here.

What about support for databinding to public fields on the Pocos?

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