Razor syntax - how to conditionally wrap some inner HTML

Question

In Razor, there\'s a curious rule about only allowing closed HTML within an if block.

See:

Razor doesn't understand unclosed ht

Answer 1

The following code is based on the answer of @JotaBe, but simplified and extendable:

public static class HtmlHelperExtensions
{
    public static IDisposable BeginTag(this HtmlHelper htmlHelper, string tagName, bool condition = true, object htmlAttributes = null)
    {
        return condition ? new DisposableTagBuilder(tagName, htmlHelper.ViewContext, htmlAttributes) : null;
    }
}

public class DisposableTagBuilder : TagBuilder, IDisposable
{
    protected readonly ViewContext viewContext;
    private bool disposed;

    public DisposableTagBuilder(string tagName, ViewContext viewContext, object htmlAttributes = null) : base(tagName)
    {
        this.viewContext = viewContext;

        if (htmlAttributes != null)
        {
            this.MergeAttributes(HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes));
        }

        this.Begin();
    }

    protected virtual void Begin()
    {
        this.viewContext.Writer.Write(this.ToString(TagRenderMode.StartTag));
    }

    protected virtual void End()
    {
        this.viewContext.Writer.Write(this.ToString(TagRenderMode.EndTag));
    }

    public void Dispose()
    {
        this.Dispose(true);
        GC.SuppressFinalize(this);
    }

    protected virtual void Dispose(bool disposing)
    {
        if (!this.disposed)
        {
            this.disposed = true;

            this.End();
        }
    }
}

This can be used the following way within Razor views:

@using (Html.BeginTag("div"))
{
    
This paragraph is rendered within a div
}

@using (Html.BeginTag("div", false))
{
    
This paragraph is rendered without the div
}

@using (Html.BeginTag("a", htmlAttributes: new { href = "#", @class = "button" }))
{
    And a lot more is possible!
}