What is the difference between Html Hidden and Html HiddenFor

Question

I can find a good definition for Html HiddenFor on MSDN but the only thing I can find on Html Hidden is related to problems it has   Can someone give me a good definition and an example

User · Answer

Every method in HtmlHelper class has a twin with For suffix   Html Hidden takes a string as an argument that you must provide but Html HiddenFor takes an Expression that if you view is a strongly typed view you can benefit from this and feed that method a lambda expression like this   o  gt o SomeProperty    instead of  SomeProperty  in the case of using Html Hidden method

User · Answer

Html Hidden and Html HiddenFor used to generate name-value pairs which waited by action method in controller   Sample Usage       using  Html BeginForm  RemoveFromCart    Cart                           Html Hidden  ProductId   line Product ProductID                       Html HiddenFor x   gt  x ReturnUrl                       lt input class  btn btn-sm btn-warning                             type  submit  value  Remove    gt                      If your action method wait for  ProductId  you have to generate this name in form via using  Html Hidden or Html HiddenFor  For the case it is not possible to generate this name with strongly typed model you simple write this name with a string thats  ProductId    public ViewResult RemoveFromCart int productId  string returnUrl         If I had written Html HiddenFor x    line Product ProductID   the helper would render a hidden field with the name  line Product ProductID        The name of the field would not match the names of the parameters for the   RemoveFromCart  action method which waiting the name of  ProductId   This would prevent the default model binders from working  so the MVC Framework would not be able to call the method    Adam Freeman  Apress - Pro ASP Net MVC 5

User · Answer

Most of the MVC helper methods have a XXXFor variant   They are intended to be used in conjunction with a concrete model class    The idea is to allow the helper to derive the appropriate  name  attribute for the form-input control based on the property you specify in the lambda   This means that you get to eliminate  magic strings  that you would otherwise have to employ to correlate the model properties with your views   For example   Html Hidden  Name    Value     Will result in    lt input id  Name  name  Name  type  hidden  value  Value  gt    In your controller  you might have an action like    HttpPost  public ActionResult MyAction MyModel model         And a model like   public class MyModel        public string Name   get  set        The raw Html Hidden we used above will get correlated to the Name property in the model   However  it s somewhat distasteful that the value  Name  for the property must be specified using a string   Name     If you rename the Name property on the Model  your code will break and the error will be somewhat difficult to figure out     On the other hand  if you use HiddenFor  you get protected from that   Html HiddenFor x   gt  x Name   Value      Now  if you rename the Name property  you will get an explicit runtime error indicating that the property can t be found   In addition  you get other benefits of static analysis  such as getting a drop-down of the members after typing x

User · Answer

Html Hidden  name    value   creates a hidden tag with name    name  and value    value    Html HiddenFor x    x nameProp  creates a hidden tag with a name    nameProp  and value   x nameProp   At face value these appear to do similar things  with one just more convenient than the other   But its actual value is for model binding   When MVC tries to associate the html to the model  it needs to have the name of the property  and for Html Hidden  we chose  name   and not  nameProp   and thus the binding wouldn t work   You d have to have a custom binding object  or get the values from the form data   If you are redisplaying the page  you d have to set the model to the values again   So you can use Html Hidden  but if you get the name wrong  or if you change the property name in the model  the auto binding will fail when you submit the form   But by using a type checked expression  you ll get code completion  and when you change the property name  you will get a compile time error   And then you are guaranteed to have the correct name in the form   One of the better features of MVC

User · Answer

The Html Hidden creates a hidden input but you have to specify the name and all the attributes you want to give that field and value  The Html HiddenFor creates a hidden input for the object that you pass to it  they look like this   Html Hidden  yourProperty  model yourProperty    Html HiddenFor m   gt  m yourProperty    In this case the output is the same

[c#] What is the difference between Html.Hidden and Html.HiddenFor

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