也许这个(?):

<%= 
  Request.Url.GetLeftPart(UriPartial.Authority) + 
  Url.Action("Action1", "Controller2", new {param1="bla", param2="blabla" })
%>

<%= Url.Action("About", "Home", null, Request.Url.Scheme) %>
<%= Url.RouteUrl("Default", new { Action = "About" }, Request.Url.Scheme) %>

点击这里获取更多信息，但基本上不需要扩展方法。它已经存在了，只是不是以非常直观的方式。

Url.Action("Action", null, null, Request.Url.Scheme);

我不确定是否有一个内置的方法来做到这一点，但你可以滚动你自己的HtmlHelper方法。

如下所示

namespace System.Web.Mvc
{
    public static class HtmlExtensions
    {
        public static string AbsoluteAction(this HtmlHelper html, string actionUrl)
        {
            Uri requestUrl = html.ViewContext.HttpContext.Request.Url;

            string absoluteAction = string.Format("{0}://{1}{2}",
                                                  requestUrl.Scheme,
                                                  requestUrl.Authority,
                                                  actionUrl);

            return absoluteAction;
        }
    }
}

然后这样叫它

<%= Html.AbsoluteAction(Url.Action("Dashboard", "Account"))%> »

HTHs, 查尔斯

带参数的完整答案是:

var url = Url.Action("ActionName", "ControllerName", new { id = "arg_value" }, Request.Url.Scheme);

那会产生一个绝对url

相同的结果，但稍微干净一点(没有字符串连接/格式化):

public static Uri GetBaseUrl(this UrlHelper url)
{
    Uri contextUri = new Uri(url.RequestContext.HttpContext.Request.Url, url.RequestContext.HttpContext.Request.RawUrl);
    UriBuilder realmUri = new UriBuilder(contextUri) { Path = url.RequestContext.HttpContext.Request.ApplicationPath, Query = null, Fragment = null };
    return realmUri.Uri;
}

public static string ActionAbsolute(this UrlHelper url, string actionName, string controllerName)
{
    return new Uri(GetBaseUrl(url), url.Action(actionName, controllerName)).AbsoluteUri;
}