JQuery Tooltips with MVC3 and CSS 3.0 (Part 2)

by Admin 25. March 2012 02:56

So in my previous post I explained all of the steps required to create a simple but effective CSS 3 JQuery tooltip implementation.  This was a good start, I had all I needed to fulfill my requirement of a consistent tooltip in my application.  But I needed it to be a little easier to use throughout the application.  A custom Html Helper Extension to the rescue. Creating an HTML Helper is a pretty straight forward task this one, however, needed a bit of special sauce to make it work the way I wanted.

First I wanted to make sure I could bind it to my model, in case in the future I wanted to default it to the [Display] property on the model.  Second I wanted to be able to use the @<text></text> syntax for the contents of the tooltip.  It made sense to work backwards I wanted the control to work like this: 

@Html.InfoTooltipFor(model => model.ToolTipTitle,
			<b>Scott Guthrie</b> – 
			<a href="http://weblogs.asp.net/scottgu/">
				ScottGu's Blog
			</a> One of the best resources for all things Microsoft Web
			<b>Scott Hanselman</b> – 
				<a href="http://www.hanselman.com/blog/">
					Scott Hanselman's Computer Zen
				</a> Another great resource very current and very informative.
			<b>ASP.NET</b> – 
				<a href="http://www.asp.net/mvc">
				</a> The mother of all things ASP.NET MVC


Seemed simple enough so at first I create the Helper as follows:


public static MvcHtmlString InfoTooltipFor<TModel, TValue>(
    this HtmlHelper<TModel> html, 
    Expression<Func<TModel, TValue>> expression, 
    string tooltip)


Nope that won't work... 


And once I thought about it makes sense that a string won't work.  It isn't anything remotely like a string it contains functions, delegates and properties. I know this type of implementation exists I have seen it in other controls.  So how is it done?  After an exhaustive google search I found this article by Phil Haack.  It was close to what I needed, so, after some trial and error I came up with this:

public static MvcHtmlString InfoTooltipFor<TModel, TValue>(this HtmlHelper<TModel> html, 
		Expression<Func<TModel, TValue>> expression, 
		Func<object, HelperResult> tooltip)
	//Get the Model metadata
	ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);
	string htmlFieldName = ExpressionHelper.GetExpressionText(expression);
	string tooltipId = metadata.PropertyName ? ? htmlFieldName.Split('.').Last();

	if (String.IsNullOrEmpty(tooltipId))
		return MvcHtmlString.Empty;
	//creates the span tag for the image
	TagBuilder spanTag = new TagBuilder("span");
	spanTag.MergeAttribute("class", "tooltipItem");
	spanTag.MergeAttribute("id", tooltipId);
	spanTag.MergeAttribute("data-tooltip", "tt" + tooltipId);

	TagBuilder imgTag = new TagBuilder("img");
	imgTag.MergeAttributes(new RouteValueDictionary(
			@class = "infoimage",
			src = UrlHelper.GenerateContentUrl("~/Content/info.png", html.ViewContext.HttpContext),
			alt = "info"
	spanTag.InnerHtml = imgTag.ToString(TagRenderMode.Normal);

	//creates the tooltip contents
	TagBuilder tooltipTag = new TagBuilder("div");
	tooltipTag.MergeAttribute("class", "hidden");
	tooltipTag.MergeAttribute("id", "tt" + tooltipId);
	tooltipTag.MergeAttribute("name", "tt" + tooltipId);
	tooltipTag.MergeAttribute("data-tooltip", "tt" + tooltipId);
	tooltipTag.InnerHtml = tooltip(null).ToString();

	return MvcHtmlString.Create(spanTag.ToString(TagRenderMode.Normal) + tooltipTag.ToString(TagRenderMode.Normal));

The key is Func<object, HelperResult> this allows templated items to be passed into helper method.  This was exactly what I needed and poof like magic it worked.  MVC is awesome, creating a control like that in standard ASP.NET would have been a major pain. 

The entire solution is in the attached zip...

EasyTooltips.zip (2.46 mb)

Tags: , , , ,

AJAX | css | jquery | MVC3

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