Pass parameter to controller from Html ActionLink MVC 4

Question

In this line    Html ActionLink  Reply    BlogReplyCommentAdd    Blog            new   blogPostId   blogPostId  replyblogPostmodel   Model           captchaValid   Model AddNewComment DisplayCaptcha      I get the following runtime error on blogPostId      The parameters dictionary contains a null entry for parameter    blogPostId  of non-nullable type  System Int32  for method    System Web Mvc ActionResult BlogReplyCommentAdd Int32    Nop Web Models Blogs BlogPostModel  Boolean   in    Nop Web Controllers BlogController   An optional parameter must be a   reference type  a nullable type  or be declared as an optional   parameter  Parameter name  parameters   I have already assign a value for this on top such as                           var blogPostId   Model Id                     My Controller    public ActionResult BlogReplyCommentAdd int blogPostId  BlogPostModel model  bool captchaValid           Am I doing something wrong  Please give me an example

User · Answer

You can pass values by using the below     Html ActionLink  About    About    Home  new   name   ViewBag Name    htmlAttributes null     Controller    public ActionResult About string name                        ViewBag Message    Your application description page                ViewBag NameTransfer   name              return View                And the URL looks like   http   localhost 50297 Home About name My 20Name 20is 20Vijay

User · Answer

I have to pass two parameters like       Controller Action Param1Value Param2Value   This way    Html ActionLink      linkText      actionName      controllerName      routeValues  new           Param1Name  Param1Value           Param2Name   Param2Value             htmlAttributes  null     will generate this url      Controller Action Param1Value Param2Name Param2Value   I used a workaround method by merging parameter two in parameter one and I get what I wanted    Html ActionLink      linkText      actionName      controllerName      routeValues  new           Param1Name   Param1Value   Param2Value                     htmlAttributes  null     And I get         Controller Action Param1Value Param2Value

User · Answer

You are using a wrong overload of the Html ActionLink helper  What you think is routeValues is actually htmlAttributes  Just look at the generated HTML  you will see that this anchor s href property doesn t look as you expect it to look   Here s what you are using    Html ActionLink       Reply                                                       linkText      BlogReplyCommentAdd                                         actionName      Blog                                                        routeValues     new                                                          htmlAttributes         blogPostId   blogPostId           replyblogPostmodel   Model           captchaValid   Model AddNewComment DisplayCaptcha            and here s what you should use    Html ActionLink       Reply                                                       linkText      BlogReplyCommentAdd                                         actionName      Blog                                                        controllerName     new                                                          routeValues         blogPostId   blogPostId           replyblogPostmodel   Model           captchaValid   Model AddNewComment DisplayCaptcha             null                                                         htmlAttributes     Also there s another very serious issue with your code  The following routeValue   replyblogPostmodel   Model   You cannot possibly pass complex objects like this in an ActionLink  So get rid of it and also remove the BlogPostModel parameter from your controller action  You should use the blogPostId parameter to retrieve the model from wherever this model is persisted  or if you prefer from wherever you retrieved the model in the GET action   public ActionResult BlogReplyCommentAdd int blogPostId  bool captchaValid        BlogPostModel model   repository Get blogPostId               As far as your initial problem is concerned with the wrong overload I would recommend you writing your helpers using named parameters    Html ActionLink      linkText   Reply       actionName   BlogReplyCommentAdd       controllerName   Blog       routeValues  new           blogPostId   blogPostId           captchaValid   Model AddNewComment DisplayCaptcha            htmlAttributes  null     Now not only that your code is more readable but you will never have confusion between the gazillions of overloads that Microsoft made for those helpers

User · Answer

The problem must be with the value Model Id which is null  You can confirm by assigning a value  e g                   var blogPostId   1                 If the error disappers  then u need to make sure that your model Id has a value before passing it to the view

[razor] Pass parameter to controller from @Html.ActionLink MVC 4

Examples related to razor

Examples related to asp.net-mvc-4