StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

POASP.NET MVC - Html.Textbox() throws "Object reference not set to an instance of an object"
text
Body
copied!<p>I've encountered a strange issue....when I use <code>UpdateModel()</code> or <code>TryUpdateModel()</code>, everything works fine. When I try binding myself (e.g. <code>MyObject.FirstName = collection["FirstName"]</code>), I get a <code>"Object reference not set to an instance of an object"</code> error.</p> <p>It's a little hard to explain, so I'll present the code:</p> <pre><code> [HandleError] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Create(FormCollection collection) { try { Model.Event evnt = new Redline.RedlineTimeAttack.Model.Event(); //When this is uncommented everything works fine. //TryUpdateModel<Model.Event>(evnt); //this will eventually lead to problems evnt.Description = collection["Description"]; evnt.EndDate = enddate; evnt.EventName = collection["EventName"]; evnt.IsActive = collection["IsActive"].Contains("true"); evnt.StartDate = startdate; evnt.TrackId = trackId; evnt.WebContent = collection["WebContent"]; if (!evnt.IsValid) { foreach (var error in evnt.GetRuleViolations()) { ModelState.AddModelError(error.PropertyName, error.ErrorMessage); } } //If there are no validation issues then no problem, redirecttoaction //works properly if (ModelState.IsValid) { model.Events.InsertOnSubmit(evnt); model.SubmitChanges(); ViewData["ControlMode"] = "Edit"; return RedirectToAction("Edit"); } else //returning to View so that user can correct issues causes a null reference error in the view (bombs at first Html.Textbox("ControlName")) { ViewData["Tracks"] = GetTracks(); return View("Create", evnt); } } </code></pre> <p>Here's the stack trace:</p> <pre><code>System.NullReferenceException was unhandled by user code Message="Object reference not set to an instance of an object." Source="System.Web.Mvc" StackTrace: at System.Web.Mvc.HtmlHelper.GetModelStateValue(String key, Type destinationType) at System.Web.Mvc.Html.InputExtensions.InputHelper(HtmlHelper htmlHelper, InputType inputType, String name, Object value, Boolean useViewData, Boolean isChecked, Boolean setId, Boolean isExplicitValue, IDictionary`2 htmlAttributes) at System.Web.Mvc.Html.InputExtensions.TextBox(HtmlHelper htmlHelper, String name, Object value, IDictionary`2 htmlAttributes) at System.Web.Mvc.Html.InputExtensions.TextBox(HtmlHelper htmlHelper, String name) at ASP.views_event_create_aspx.__RenderContent2(HtmlTextWriter __w, Control parameterContainer) in d:\TFSProjects\Redline Time Attack\Main\Source\Redline.RedlineTimeAttack.Web\Views\Event\Create.aspx:line 18 at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at System.Web.UI.Control.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at ASP.views_shared_site_master.__Render__control1(HtmlTextWriter __w, Control parameterContainer) in d:\TFSProjects\Redline Time Attack\Main\Source\Redline.RedlineTimeAttack.Web\Views\Shared\Site.Master:line 29 at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at System.Web.UI.Control.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at System.Web.UI.Page.Render(HtmlTextWriter writer) at System.Web.Mvc.ViewPage.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) InnerException: </code></pre>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload