HTMLHelper.Beginform query

I'm learning about HTMLHelpers in ASP.NET MVC.

To render the form HTML tag you would write something like

<% using(Html.BeginForm("HandleForm", "Home")) {%>
    <!--Form content goes here-->
<% } %>

or

<% Html.BeginForm(); %>
… Form Contents …
<% Html.EndForm(); %>

To render the a checkbox you would use

<%= Html.CheckBox("bookType") %>

What I would like to know 开发者_如何学运维is is why we need to use <% when we use BeginForm whereas we need to use <%= when we use other HTMLHelper methods

Cheers,

Html.CheckBox returns a string of HTML containing an <input> tag.
You need to print this string to the page by writing <%= ... %>.

Html.BeginForm prints the HTML inside the method (by calling Response.Write), and doesn't return HTML. (instead, it returns an IDisposable, so that you can use it in a using block)
Since you aren't printing its return value, you put it in a <% ... %> block, which executes code without printing its results.

<% %> wraps a code block

<%="string" %> is equivalent to <% Response.Write("string") %>

and in ASP.NET MVC 3 you can automatically HtmlEncode with <%: "<htmlTag>" %>

You can definitely write <%=Html.BeginForm() %> but you will also need to write <%=Html.EndForm() %>. Wrapping Html.BeginForm() within a using block will just render the closing </form> tag for you.

Because <%= means "Print this for me", pretty much the same as doing:

<% Response.Write("content"); %>

When <% means that you have a code-block that might do more than just print the value you have nested in it.