MVC3 ActionLink with images (but without MvcFutures)?

问题

I was wondering if anyone knows if it possible to use any of the "out of the box" ASP.NET MVC3 helpers to generate a "link button"...I currently use following:

<a class="button" title="My Action" href="@Url.Action("MyAction", "MyController", new { id = item.Id })">
    <img alt="My Action" src="@Url.Content("~/Content/Images/MyLinkImage.png")" />
</a>

I am trying to avoid using MvcFutures, but even if I was able to use them, I don't think there is a extension method it there that will accomplish this either. (I believe solution in this case would be to roll custom helper as seen here)

Finally, this post also has a good idea to handle this via CSS, but that is not what I am asking...

回答1:

I am using the following to generate action links:

using System;
using System.Linq.Expressions;
using System.Text;
using System.Web.Mvc;
using System.Web.Mvc.Html;
using System.Web.Routing;
using Fasterflect;

namespace StackOverflow.Mvc.Extensions
{
    public static class HtmlExtensions
    {
        #region ActionImage
        // href image link
        public static string ActionImage( this HtmlHelper helper, string href, string linkText, object htmlAttributes,
                                          string alternateText, string imageSrc, object imageAttributes )
        {
            var sb = new StringBuilder();
            const string format = "<a href=\"{0}\"{1}>{2}</a>";
            string image = helper.Image( imageSrc, alternateText, imageAttributes ).ToString();
            string content = string.IsNullOrWhiteSpace( linkText ) ? image : image + linkText;
            sb.AppendFormat( format, href, GetAttributeString( htmlAttributes ), content );
            return sb.ToString();
        }

        // controller/action image link
        public static string ActionImage( this HtmlHelper helper, string controller, string action, string linkText, object htmlAttributes,
                                          string alternateText, string imageSrc, object imageAttributes )
        {
            bool isDefaultAction = string.IsNullOrEmpty( action ) || action == "Index";
            string href = "/" + (controller ?? "Home") + (isDefaultAction ? string.Empty : "/" + action);
            return ActionImage( helper, href, linkText, htmlAttributes, alternateText, imageSrc, imageAttributes );
        }

        // T4MVC ActionResult image link
        public static string ActionImage( this HtmlHelper helper, ActionResult actionResult, string linkText, object htmlAttributes,
                                          string alternateText, string imageSrc, object imageAttributes )
        {
            var controller = (string) actionResult.GetPropertyValue( "Controller" );
            var action = (string) actionResult.GetPropertyValue( "Action" );
            return ActionImage( helper, controller, action, linkText, htmlAttributes, alternateText, imageSrc, imageAttributes );
        }       
        #endregion

        #region Helpers
        private static string GetAttributeString( object htmlAttributes )
        {
            if( htmlAttributes == null )
            {
                return string.Empty;
            }
            const string format = " {0}=\"{1}\"";
            var sb = new StringBuilder();
            htmlAttributes.GetType().Properties().ForEach( p => sb.AppendFormat( format, p.Name, p.Get( htmlAttributes ) ) );
            return sb.ToString();
        }       
        #endregion
    }
}

Note that the GetAttributeString method relies on the Fasterflect library to make reflection tasks easier, but you can replace that with regular reflection if you prefer not to take the additional dependency.

The Image helper extension used to be part of MvcContrib but appears to have been removed, most likely because the functionality is now built in to MVC. Regardless, I've included it below for completeness:

public static class ImageExtensions {
    public static MvcHtmlString Image(this HtmlHelper helper, string imageRelativeUrl, string alt, object htmlAttributes) {
        return Image(helper, imageRelativeUrl, alt, new RouteValueDictionary(htmlAttributes));
    }

    public static MvcHtmlString Image(this HtmlHelper helper, string imageRelativeUrl, string alt, IDictionary<string, object> htmlAttributes) {
        if (String.IsNullOrEmpty(imageRelativeUrl)) {
            throw new ArgumentException(MvcResources.Common_NullOrEmpty, "imageRelativeUrl");
        }

        string imageUrl = UrlHelper.GenerateContentUrl(imageRelativeUrl, helper.ViewContext.HttpContext);
        return MvcHtmlString.Create(Image(imageUrl, alt, htmlAttributes).ToString(TagRenderMode.SelfClosing));
    }

    public static TagBuilder Image(string imageUrl, string alt, IDictionary<string, object> htmlAttributes) {
        if (String.IsNullOrEmpty(imageUrl)) {
            throw new ArgumentException(MvcResources.Common_NullOrEmpty, "imageUrl");
        }

        TagBuilder imageTag = new TagBuilder("img");

        if (!String.IsNullOrEmpty(imageUrl)) {
            imageTag.MergeAttribute("src", imageUrl);
        }

        if (!String.IsNullOrEmpty(alt)) {
            imageTag.MergeAttribute("alt", alt);
        }

        imageTag.MergeAttributes(htmlAttributes, true);

        if (imageTag.Attributes.ContainsKey("alt") && !imageTag.Attributes.ContainsKey("title")) {
            imageTag.MergeAttribute("title", (imageTag.Attributes["alt"] ?? "").ToString());
        }
        return imageTag;
    }
}

回答2:

The snippet you have looks quite good. You should wrap it in a general-purpose html helper and call it a day. I'm sure there are other more interesting aspects to your application than nit picking about UI helpers :)

回答3:

Check at the bottom of this blog post for an example with HTML extension methods from Stephen Walther

来源：https://stackoverflow.com/questions/5111110/mvc3-actionlink-with-images-but-without-mvcfutures