.net - Custom html helpers: Create helper with "using" statement support

Question

I'm writing my first asp.net mvc application and I have a question about custom Html helpers:

For making a form, you can use:

<% using (Html.BeginForm()) {%>
   *stuff here*
<% } %>

I would like to do something similar with a custom HTML helper. In other words, I want to change:

Html.BeginTr();
Html.Td(day.Description);
Html.EndTr();

into:

using Html.BeginTr(){
    Html.Td(day.Description);
}

Is this possible?

question from:https://stackoverflow.com/questions/676746/custom-html-helpers-create-helper-with-using-statement-support

Answer 1

Here is a possible reusable implementation in c# :

class DisposableHelper : IDisposable
{
    private Action end;

    // When the object is created, write "begin" function
    public DisposableHelper(Action begin, Action end)
    {
        this.end = end;
        begin();
    }

    // When the object is disposed (end of using block), write "end" function
    public void Dispose()
    {
        end();
    }
}

public static class DisposableExtensions
{
    public static IDisposable DisposableTr(this HtmlHelper htmlHelper)
    {
        return new DisposableHelper(
            () => htmlHelper.BeginTr(),
            () => htmlHelper.EndTr()
        );
    }
}

In this case, BeginTr and EndTr directly write in the response stream. If you use extension methods that return a string, you'll have to output them using :

htmlHelper.ViewContext.HttpContext.Response.Write(s)