MVC 4 - Return error message from Controller - Show in View

Question

I am doing a C  project using Razor in VS2010  MVC 4   I need to return an error message from Controller to View and show it to the user  What I have tried   CONTROLLER     HttpPost   public ActionResult form edit FormModels model                   model error msg   model update content model                  ModelState AddModelError  error    adfdghdghgdhgdhdgda        ViewBag error   TempData  error        return RedirectToAction  Form edit    Form          VIEW    model mvc cs Models FormModels  using ctrlr   mvc cs Controllers FormController    using  Html BeginForm  form edit    Form   FormMethod Post               lt table gt           lt tr gt           lt td gt                  Html ValidationSummary  error                   Html ValidationMessage  error                  lt  td gt           lt  tr gt       lt tr gt           lt th gt               Html DisplayNameFor model   gt  model content name               Html DropDownListFor x   gt  x selectedvalue  new SelectList Model Countries  Model dd value  Model dd text    -- Select Product--             lt  th gt       lt  tr gt   lt  table gt    lt table gt       lt tr gt           lt td gt               lt input  type  submit  value  Submit    gt           lt  td gt       lt  tr gt   lt  table gt      Please help me to achieve this

User · Answer

Thanks for all the replies   I was able to solve this by doing the following   CONTROLLER    HttpPost         public ActionResult form edit FormModels model      model error msg   model update content model     return RedirectToAction  Form edit    Form   model      public ActionResult form edit FormModels model  string searchString string id      string test   model selectedvalue    var bal   new FormModels      bal Countries   bal get contentdetails searchString     bal selectedvalue   id    bal dd text    content name     bal dd value    content id      test   model error msg    ViewBag head    Heading      if  model error msg    null          ModelState AddModelError  error msg   test          model error msg         return View bal          VIEW    using  Html BeginForm  form edit    Form   FormMethod Post        lt table gt       lt tr gt         lt td gt           ViewBag error          Html ValidationMessage  error msg          lt  td gt       lt  tr gt       lt tr gt         lt th gt           Html DisplayNameFor model   gt  model content name           Html DropDownListFor x   gt  x selectedvalue  new SelectList Model Countries  Model dd value  Model dd text    -- Select Product--          lt  th gt       lt  tr gt     lt  table gt

User · Answer

The Return View model  returns you error because you don t fill the model with the values in your post method and the model data for the dropdown is empty  Please provide the Get method to explain further how to manage displaying the error  In order to the error to be shown you should use this    HttpPost  public ActionResult form edit FormModels model                 if ModelState IsValid               --- operations        return Redirect  OtherAction    SomeController                here you can use a little trick      fill the model property that holds the information for the dropdown with the data         you haven t provided the get method but it should look something like this    model Countries       some data goes here     model dd value       some other data     model dd text       other data      ModelState AddModelError      adfdghdghgdhgdhdgda       return View model       and then in the view just use     model mvc cs Models FormModels  using ctrlr   mvc cs Controllers FormController    using  Html BeginForm  form edit    Form   FormMethod Post           lt table gt       lt tr gt       lt td gt              Html ValidationSummary true                    lt  td gt       lt  tr gt   lt tr gt       lt th gt           Html DisplayNameFor model   gt  model content name           Html DropDownListFor x   gt  x selectedvalue  new SelectList Model Countries  Model dd value  Model dd text    -- Select Product--         lt  th gt   lt  tr gt   lt  table gt    lt table gt   lt tr gt       lt td gt           lt input  type  submit  value  Submit    gt       lt  td gt   lt  tr gt   lt  table gt      This should work okay   If you just use RedirectToAction it will redirect you to the get method --  you will have no error but the view will be just reloaded and no error would be shown   other way around is that you can pass the error not by ModelState AddError  but with ViewData  error   like this    HttpPost  public ActionResult form edit FormModels model                 TempData  error      someErrorMessage      return RedirectToAction  form Post    Form        HttpGet  public ActionResult form edit         do stuff here ----     ViewData  error     TempData  error        return View        model mvc cs Models FormModels  using ctrlr   mvc cs Controllers FormController    using  Html BeginForm  form edit    Form   FormMethod Post           lt table gt       lt tr gt       lt td gt              lt div gt  ViewData  error   lt  div gt                    lt  td gt       lt  tr gt   lt tr gt       lt th gt           Html DisplayNameFor model   gt  model content name           Html DropDownListFor x   gt  x selectedvalue  new SelectList Model Countries  Model dd value  Model dd text    -- Select Product--         lt  th gt   lt  tr gt   lt  table gt    lt table gt   lt tr gt       lt td gt           lt input  type  submit  value  Submit    gt       lt  td gt   lt  tr gt   lt  table gt

User · Answer

You can add this to your  Layout cshtml    using MyProj ViewModels           if  TempData  UserMessage      null                var message    MessageViewModel TempData  UserMessage             lt div class  alert  message CssClassName  role  alert  gt               lt button type  button  class  close  data-dismiss  alert  aria-label  Close  gt                   lt span aria-hidden  true  gt  amp times  lt  span gt               lt  button gt               lt strong gt  message Title lt  strong gt               message Message          lt  div gt          Then if you want to throw an error message in your controller       TempData  UserMessage     new MessageViewModel     CssClassName    alert-danger  alert-dismissible   Title    Error   Message    This is an error message       MessageViewModel cs   public class MessageViewModel               public string CssClassName   get  set            public string Title   get  set            public string Message   get  set            Note  Using Bootstrap 4 classes

User · Answer

If you want to do a redirect  you can either   ViewBag Error    error message     or  TempData  Error      error message

[asp.net-mvc-4] MVC 4 - Return error message from Controller - Show in View

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