CODEWITHSUNDEEP
asp.net-mvc
psj01
psj01

Reputation: 3245

Why does Html.BeginForm needs to be wrapped inside curly braces?

Why does begin form needs to be wrapped inside curly braces like this:

@{Html.BeginForm();}
    // some other stuff....
    <input type="submit" name="Submit" />
@{ Html.EndForm();}

Vs. if I just want a label I can simply do :

@Html.Label("Hi")

When I tried @Html.BeginForm() with out the curly braces I simply get

System.Web.Mvc.Html.MvcForm

printed on the screen.

Upvotes: 1

Views: 613

Answers (3)

Guicb
Guicb

Reputation: 61

The @Html.BeginForm Writes an opening tag to the response, and the @Html.Label it's a method that returns an HTML label element and dont need to open and close braces.

You dont need to use Begin and End.

You could use like that:

@using (Html.BeginForm())
  {
     // some other stuff....
     <input type="submit" name="Submit" />
  }

The braces of @using will do the Html.EndForm for you.

Upvotes: 1

Tetsuya Yamamoto
Tetsuya Yamamoto

Reputation: 24957

Here is an explanation from remarks section of BeginForm reference (emphasis mine):

The BeginForm method renders a form that will be handled by a controller action method.

You can use this method in a using block. In that case, the method renders the closing </form> tag at the end of the using block.

If you call @Html.BeginForm() method without code block or using block, it treated as standard Razor expression (HTML encoded) and implicitly calls ToString() method, hence the type name System.Web.Mvc.Html.MvcForm will shown instead of opening <form> tag.

When BeginForm used inside using block, it renders both opening <form> and closing </form> tag in HTML output, hence this using block:

@using (Html.BeginForm())
{
    <input type="submit" name="Submit" />
}

will transformed to HTML output like this:

<form>
    <input type="submit" name="Submit" />
</form>

Note that Html.BeginForm returns IDisposable object which automatically calls Html.EndForm() on disposal, hence no need to use Html.EndForm() after using block.

Second, @Html.Label(...) helper not requires code block because it derived from System.Web.Mvc.HtmlHelper namespace that returns MvcHtmlString, which renders both <label> and </label> tag simultaneously.

As a side note, if you trying to use @Html.EndForm() outside code block (wrapped with @{ ... }), this exception will thrown because Html.EndForm is a void method which Write(void) turns into compile-time error:

The best overloaded method match for 'System.Web.WebPages.WebPageExecutingBase.Write(System.Web.WebPages.HelperResult)' has some invalid arguments.

Additional reference:

Razor Syntax Quick Reference

Upvotes: 2

RickL
RickL

Reputation: 3393

Razor compound @using - in C#, a using statement is used to ensure an object is disposed. In Razor, the same mechanism is used to create HTML Helpers that contain additional content.

Here is a good Razor syntax reference article that goes into more detail, including the syntax for @using (Html.BeginForm())

Upvotes: 2

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