我正在开发一个服务器端 Blazor 应用程序，它使用 EntityFramework-Core 创建数据库（代码优先）。我想在 EditForm 组件中使用其中一个模型，但每当我打开包含 EditForm 组件的页面时，它都会在 _Host.cshtml 上引发 NullReferenceException。其他页面工作完全正常！ Rider 屏幕截图中的错误 这是页面上给出的错误：
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 Routing
NullReferenceException: 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) …