MVC ActionLink从当前url添加所有(可选)参数

Question

非常有名的ActionLink:

 <%: Html.ActionLink("Back to List", "Index")%>

现在,此链接位于我的详细信息视图中.索引视图是搜索页面.其URL如下所示:

http://localhost:50152/2011-2012/Instelling/Details/76?gemeente=Dendermonde&postcode=92**&gebruikerscode=VVKSO114421&dossiernr=114421%20&organisatie=CLB

如你所见,相当多的参数.显然我想在返回索引页面时保留所有这些参数,所以我需要将它们添加到ActionLink.

现在,我已经厌倦了手动操作,它可以1,但不适用于6.这应该会更容易.

问题:如何将当前URL的所有参数都返回ActionLink为可选RouteValues.

我一直在寻找Request.QueryString.它必须是那样的东西.我在考虑编写一些静态方法Global.asax来完成工作,但还没有运气.也许有一种简单的方法可以做到这一点我不知道？

编辑:这是我想出的(哪个有效)

在global.asax中:

    public static RouteValueDictionary optionalParamters(NameValueCollection c) {
        RouteValueDictionary r = new RouteValueDictionary();
        foreach (string s in c.AllKeys) {
            r.Add(s, c[s]);
        }
        return r;
    }

Details.aspx:

    <%: Html.ActionLink("Back to List", "Index", MVC2_NASTEST.MvcApplication.optionalParamters(Request.QueryString))%>

我最好把这段代码放在哪里？不是Global.asax我猜...

编辑2:

using System;
using System.Web.Mvc;

namespace MVC2_NASTEST.Helpers {
    public static class ActionLinkwParamsExtensions {
        public static MvcHtmlString CustomLink(this HtmlHelper helper, string linktext) {
            //here u can use helper to get View context and then routvalue dictionary
            var routevals = helper.ViewContext.RouteData.Values;
            //here u can do whatever u want with route values
            return null;
        }

    }
}


<%@ Import Namespace="MVC2_NASTEST.Helpers" %>
...
<%: Html.ActionLinkwParams("Index") %>

Answer 1

这就是我最终修复它的方式,我很自豪,因为它工作得很好而且非常干燥.

视图中的调用:

    <%: Html.ActionLinkwParams("Back to List", "Index")%>

但是有了重载,它可以是普通ActionLink所采用的任何东西.

帮助者:

帮助程序从URL中获取不在路径中的所有参数.例如:这个网址:

http://localhost:50152/2011-2012/myController/Details/77?postalCode=9***&org=CLB

因此它将采用postalCode和Org并将其放在新的ActionLink中.通过过载,可以添加其他参数,并且可以删除现有URL中的参数.

using System;
using System.Web.Mvc;
using System.Web.Routing;
using System.Collections.Specialized;
using System.Collections.Generic;

namespace MVC2_NASTEST.Helpers {
    public static class ActionLinkwParamsExtensions {
        public static MvcHtmlString ActionLinkwParams(this HtmlHelper helper, string linktext, string action, string controller, object extraRVs, object htmlAttributes) {

            NameValueCollection c = helper.ViewContext.RequestContext.HttpContext.Request.QueryString;

            RouteValueDictionary r = new RouteValueDictionary();
            foreach (string s in c.AllKeys) {
                r.Add(s, c[s]);
            }

            RouteValueDictionary htmlAtts = new RouteValueDictionary(htmlAttributes);

            RouteValueDictionary extra = new RouteValueDictionary(extraRVs);

            RouteValueDictionary m = Merge(r, extra);

            return System.Web.Mvc.Html.LinkExtensions.ActionLink(helper, linktext, action, controller, m, htmlAtts);
        }

        public static MvcHtmlString ActionLinkwParams(this HtmlHelper helper, string linktext, string action) {
            return ActionLinkwParams(helper, linktext, action, null, null, null);
        }

        public static MvcHtmlString ActionLinkwParams(this HtmlHelper helper, string linktext, string action, string controller) {
            return ActionLinkwParams(helper, linktext, action, controller, null, null);
        }

        public static MvcHtmlString ActionLinkwParams(this HtmlHelper helper, string linktext, string action, object extraRVs) {
            return ActionLinkwParams(helper, linktext, action, null, extraRVs, null);
        }

        public static MvcHtmlString ActionLinkwParams(this HtmlHelper helper, string linktext, string action, string controller, object extraRVs) {
            return ActionLinkwParams(helper, linktext, action, controller, extraRVs, null);
        }

        public static MvcHtmlString ActionLinkwParams(this HtmlHelper helper, string linktext, string action, object extraRVs, object htmlAttributes) {
            return ActionLinkwParams(helper, linktext, action, null, extraRVs, htmlAttributes);
        }




        static RouteValueDictionary Merge(this RouteValueDictionary original, RouteValueDictionary @new) {

            // Create a new dictionary containing implicit and auto-generated values
            RouteValueDictionary merged = new RouteValueDictionary(original);

            foreach (var f in @new) {
                if (merged.ContainsKey(f.Key)) {
                    merged[f.Key] = f.Value;
                } else {
                    merged.Add(f.Key, f.Value);
                }
            }

            return merged;

        }
    }

}

在使用重载的视图中:

 <%: Html.ActionLinkwParams("Back to List", "Index","myController", new {testValue = "This is a test", postalCode=String.Empty}, new{ @class="test"})%>

在URL我有paramters postalCode有一些价值.我的代码在URL中获取所有这些,通过将其设置为string.Empty,我从列表中删除此参数.

评论或想法欢迎优化它.

Answer 2

为Request.QueryString 创建一个ToRouteValueDictionary()扩展方法,以便按原样使用Html.ActionLink并简化视图标记:

<%: Html.ActionLink("Back to List", "Index", Request.QueryString.ToRouteValueDictionary())%>

您的扩展方法可能如下所示:

using System.Web.Routing;
using System.Collections.Specialized;

namespace MyProject.Extensions
{
    public static class CollectionExtensions
    {
        public static RouteValueDictionary ToRouteValueDictionary(this NameValueCollection collection)
        {
            var routeValueDictionary = new RouteValueDictionary();
            foreach (var key in collection.AllKeys)
            {
                routeValueDictionary.Add(key, collection[key]);
            }
            return routeValueDictionary;
        }
    }
}

要在视图中使用扩展方法,请参阅此问题和答案:如何在ASP.NET MVC视图中使用扩展方法？

这比接受的答案更简单,代码少得多.

Answer 3

这是ViewContext的扩展方法,它根据请求路由值和查询字符串创建RouteValueDictionary.

using System.Collections.Specialized;
using System.ComponentModel;
using System.Linq;
using System.Web.Mvc;
using System.Web.Routing;

namespace MyMvcApplication.Utilities
{
    public static class ViewContextExtensions
    {
        /// <summary>
        /// Builds a RouteValueDictionary that combines the request route values, the querystring parameters,
        /// and the passed newRouteValues. Values from newRouteValues override request route values and querystring
        /// parameters having the same key.
        /// </summary>
        public static RouteValueDictionary GetCombinedRouteValues(this ViewContext viewContext, object newRouteValues)
        {
            RouteValueDictionary combinedRouteValues = new RouteValueDictionary(viewContext.RouteData.Values);

            NameValueCollection queryString = viewContext.RequestContext.HttpContext.Request.QueryString;
            foreach (string key in queryString.AllKeys.Where(key => key != null))
                combinedRouteValues[key] = queryString[key];

            if (newRouteValues != null)
            {
                foreach (PropertyDescriptor descriptor in TypeDescriptor.GetProperties(newRouteValues))
                    combinedRouteValues[descriptor.Name] = descriptor.GetValue(newRouteValues);
            }


            return combinedRouteValues;
        }
    }
}

您可以将创建的RouteValueDictionary传递给Html.ActionLink或Url.Action

@Html.ActionLink("5", "Index", "Product",
    ViewContext.GetCombinedRouteValues(new { Page = 5 }),
    new Dictionary<string, object> { { "class", "page-link" } })

如果请求URL中不存在Page参数,则会将其添加到生成的URL中.如果确实存在,则其值将更改为5.

本文对我的解决方案有更详细的解释.