Rendering html code using TagBuilder and ASP.NET MVC 4 (with Razor engine)

Question

I would like to render li items using TagBuilder.

My function

public static string RenderListTag(this HtmlHelper helper, string labelText, string action, string controller, bool isAdmin, string listCssClass = "")
        {
            string value = string.Empty;

            TagBuilder li = new TagBuilder("li");
            TagBuilder anchor = new TagBuilder("a");
            UrlHelper urlHelper = new UrlHelper(HttpContext.Current.Request.RequestContext);

            if (string.IsNullOrEmpty(action) || string.IsNullOrEmpty(controller))
            {
                anchor.MergeAttribute("href", "#");
            }
            else
            {
                anchor.MergeAttribute("href", urlHelper.Action(action, controller, new
                {
                    area = isAdmin ? "Admin" : ""
                }));
            }

            anchor.SetInnerText(labelText);

            if (action.IsEqualWith(helper.ViewContext.RouteData.Values["action"].ToString()))
            {
                li.MergeAttribute("class", "active");
            }

            if (!string.IsNullOrEmpty(listCssClass))
            {
                li.MergeAttribute("class", listCssClass);
            }

            li.SetInnerText(anchor.ToString(TagRenderMode.Normal));

            return li.ToString(TagRenderMode.Normal);
        }

When I call using the following code:

@Html.RenderListTag("Home", "Index", "Contents", false)
@Html.RenderListTag("About", "About", "Home", false)
@Html.RenderListTag("Contact", "Contact", "Home", false)
@Html.RenderListTag("Show toolbar", "", "", false, "options no-display")
@Html.RenderListTag("CMS", "Index", "Home", true)

The results is printed as text NOT html tag.

<li class="active">&lt;a href=&quot;/Contents&quot;&gt;Home&lt;/a&gt;</li> <li>&lt;a href=&quot;/Home/About&quot;&gt;About&lt;/a&gt;</li> <li>&lt;a href=&quot;/Home/Contact&quot;&gt;Contact&lt;/a&gt;</li> <li class="options no-display">&lt;a href=&quot;#&quot;&gt;Show toolbar&lt;/a&gt;</li> <li class="active">&lt;a href=&quot;/Admin/Home&quot;&gt;CMS&lt;/a&gt;</li> 

I want to print the HTML tag not text.

Where is my mistake ?

Answer 1

You must return a MvcHtmlString from method

public static MvcHtmlString RenderListTag(this HtmlHelper helper, string labelText, string action, string controller, bool isAdmin, string listCssClass = "")
{
    string value = string.Empty;

    TagBuilder li = new TagBuilder("li");
    TagBuilder anchor = new TagBuilder("a");
    UrlHelper urlHelper = new UrlHelper(HttpContext.Current.Request.RequestContext);

    if (string.IsNullOrEmpty(action) || string.IsNullOrEmpty(controller))
    {
        anchor.MergeAttribute("href", "#");
    }
    else
    {
        anchor.MergeAttribute("href", urlHelper.Action(action, controller, new
        {
            area = isAdmin ? "Admin" : ""
        }));
    }

    anchor.SetInnerText(labelText);

    if (action.IsEqualWith(helper.ViewContext.RouteData.Values["action"].ToString()))
    {
        li.MergeAttribute("class", "active");
    }

    if (!string.IsNullOrEmpty(listCssClass))
    {
        li.MergeAttribute("class", listCssClass);
    }

    li.SetInnerText(anchor.ToString(TagRenderMode.Normal));

    return new MvcHtmlString(li.ToString(TagRenderMode.Normal));
}

Answer 2

I found my mistake :)

I used

li.SetInnerText(anchor.ToString(TagRenderMode.Normal));

The correct way is

li.InnerHtml = anchor.ToString(TagRenderMode.Normal);

I changed type of my function from string to MvcHtmlString like:

public static MvcHtmlString RenderListTag(this HtmlHelper helper, string labelText, string action, string controller, bool isAdmin, string listCssClass = "")

And the return of function is:

return MvcHtmlString.Create(li.ToString());

Now, works.