I'm developing an server-side Blazor-application, which uses EntityFramework-Core to create the Database (code-first).I want to use one of the models in an EditForm-component, but it throws an NullReferenceException on the _Host.cshtml, whenever I open the page, containing the EditForm-component. Other pages are working completely fine!Error in Rider ScreenshotThis is the error given on the page:
An unhandled exception occurred while processing the request.NullReferenceException: Object reference not set to an instance of an object.WebApplication.Pages.Components.Customer.EditCustomer.<BuildRenderTree>b__0_4(RenderTreeBuilder __builder3)Stack Query Cookies Headers RoutingNullReferenceException: Object reference not set to an instance of an object.WebApplication.Pages.Components.Customer.EditCustomer.<BuildRenderTree>b__0_4(RenderTreeBuilder __builder3)Microsoft.AspNetCore.Components.CascadingValue<TValue>.Render(RenderTreeBuilder builder)Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment)Microsoft.AspNetCore.Components.RenderTree.Renderer.RenderInExistingBatch(RenderQueueEntry renderQueueEntry)Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.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.ComponentBase.StateHasChanged()Microsoft.AspNetCore.Components.ComponentBase.CallOnParametersSetAsync()Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.HandleException(Exception exception)Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToPendingTasks(Task task)Microsoft.AspNetCore.Components.Rendering.ComponentState.SetDirectParameters(ParameterView parameters)Microsoft.AspNetCore.Components.RenderTree.Renderer.RenderRootComponentAsync(int componentId, ParameterView initialParameters)Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.CreateInitialRenderAsync(Type componentType, ParameterView initialParameters)Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.RenderComponentAsync(Type componentType, ParameterView initialParameters)Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContext+<>c__11<TResult>+<<InvokeAsync>b__11_0>d.MoveNext()Microsoft.AspNetCore.Mvc.ViewFeatures.StaticComponentRenderer.PrerenderComponentAsync(ParameterView parameters, HttpContext httpContext, Type componentType)Microsoft.AspNetCore.Mvc.ViewFeatures.ComponentRenderer.PrerenderedServerComponentAsync(HttpContext context, ServerComponentInvocationSequence invocationId, Type type, ParameterView parametersCollection)Microsoft.AspNetCore.Mvc.ViewFeatures.ComponentRenderer.RenderComponentAsync(ViewContext viewContext, Type componentType, RenderMode renderMode, object parameters)Microsoft.AspNetCore.Mvc.TagHelpers.ComponentTagHelper.ProcessAsync(TagHelperContext context, TagHelperOutput output)Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner.<RunAsync>g__Awaited|0_0(Task task, TagHelperExecutionContext executionContext, int i, int count)WebApplication.Pages.Pages__Host.<ExecuteAsync>b__14_1() in _Host.cshtml<component type="typeof(App)" render-mode="ServerPrerendered"/>Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperExecutionContext.SetOutputContentAsync()WebApplication.Pages.Pages__Host.ExecuteAsync() in _Host.cshtml Layout = null;Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderPageCoreAsync(IRazorPage page, ViewContext context)Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderPageAsync(IRazorPage page, ViewContext context, bool invokeViewStarts)Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderAsync(ViewContext context)Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ViewContext viewContext, string contentType, Nullable<int> statusCode)Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ViewContext viewContext, string contentType, Nullable<int> statusCode)Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResultFilterAsync>g__Awaited|29_0<TFilter, TFilterAsync>(ResourceInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResultExecutedContextSealed context)Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext<TFilter, TFilterAsync>(ref State next, ref Scope scope, ref object state, ref bool isCompleted)Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeResultFilters()Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore.MigrationsEndPointMiddleware.Invoke(HttpContext context)Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)Show raw exception detailsThis is my EditCustomer-Razorcomponent:
@page "/customers/edit/"@page "/customers/edit/{CustomerId:int}"@using DataModels.Invoice@inject IToastService _toastService<AuthorizeView Context="authContext"><Authorized><h3>Edit Customer</h3><EditForm OnValidSubmit="@OnValid_Submit" Context="formContext" Model="@CurrentModel"><DataAnnotationsValidator/><ValidationSummary/><div class="form-group"><label for="CompanyName">Company Name:</label><input id="CompanyName" class="form-control" type="text"/></div><div class="form-row"><div class="form-group col-md-1"><label for="FormOfAddress">Form:</label><select id="FormOfAddress" class="form-control"><option value="1">Herr</option><option value="2">Frau</option><option value="3">Divers</option></select></div><div class="form-group col-md-3"><label for="PreName">Prename:</label><input id="PreName" class="form-control" type="text"/></div><div class="form-group col-md-3"><label for="SurName">Surname:</label><input id="SurName" class="form-control" type="text"/></div></div><div class="form-row"><div class="form-group col-md-3"><label for="Email">Email:</label><input id="Email" class="form-control" type="email"/></div><div class="form-group col-md-3"><label for="Telephone">Telephone:</label><input id="Telephone" class="form-control" type="tel"/></div></div><div class="form-row"><div class="form-group col-md-6"><label for="Address">Address:</label><input id="Address" @bind="CurrentModel.Address.StreetName" class="form-control" type="text"/></div><div class="form-group col-md-1"><label for="HouseNumber">Nr:</label><input id="HouseNumber" @bind="CurrentModel.Address.HouseNumber" class="form-control" type="text"/></div></div><div class="form-row"><div class="form-group col-md-2"><label for="ZipCode">Zip-Code:</label><input id="ZipCode" @bind="CurrentModel.Address.City.ZipCode" class="form-control" type="text"/></div><div class="form-group col-md-3"><label for="City">City:</label><input id="City" @bind="CurrentModel.Address.City.Name" class="form-control" type="text"/></div></div><div class="form-row"><div class="form-group col-md-3"><label for="UstId">Ust.Id.:</label><input id="UstId" class="form-control" type="text"/></div><div class="form-group col-md-3"><label for="CommercialRegisterNr">Commercial Register Nr.:</label><input id="CommercialRegisterNr" class="form-control" type="text"/></div></div><div class="form-group"><h4>Fields</h4><table class="table"><thead><tr><th>Key</th><th>Value</th><th>Action</th></tr></thead><tbody></tbody></table></div><button type="submit" class="btn btn-primary">Save Changes</button></EditForm></Authorized><NotAuthorized><NotPermitted/></NotAuthorized></AuthorizeView>C# code:
@code { [Parameter] public int? CustomerId { get; set; } private Customer CurrentModel { get; set; } = new(); private List<Tuple<string, string>> Fields { get; set; } private string TupleKey { get; set; } private string TupleValue { get; set; } protected override void OnInitialized() { Fields = new List<Tuple<string, string>>(); if (CustomerId is not null) { //Load from DbContext return; } CurrentModel = new Customer(); } private void OnValid_Submit(EditContext context) { Console.WriteLine("works."); }}This is my customer-model:
using System.Collections;using System.Collections.Generic;using System.ComponentModel.DataAnnotations;using System.ComponentModel.DataAnnotations.Schema;namespace DataModels.Invoice{ public class Customer { [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int Id { get; set; } public string CompanyName { get; set; } public ContactPerson ContactPerson { get; set; } public Address Address { get; set; } public string UstId { get; set; } public string CommercialRegisterNr { get; set; } public IEnumerable<CustomerInfoField>? AdditionalFields { get; set; } public IEnumerable<Invoice>? Invoices { get; set; } }}The page works when throwing in a "dummy"-class with only one or two properties in it with @bind.Would really appreciate your help since it's driving me crazy...