Question

我有一个ASP.NET MVC站点地图提供程序的问题，它给我带来了很多麻烦。当服务器负载很重时，URL被错误地解决了。我刚刚升级到最新版本（3.1.0 RC），我希望这可以修复，但不幸的是它没有。

我尝试生成本地测试来验证这一点，但我无法复制服务器上的负载。因此，我将向您展示我对实时服务器进行的单元测试：

[TestMethod]
public void ForumTopic_Breadcrumb() {
    // Arrange
    var isValid = true;

    for (var i = 0; i < 100; i++) {
        try {
            // Send the request
            var request = Http.WebRequest("http://www.mysite.com/Forum/ViewTopic/38044"); // Http.WebRequest is a utility method to send a request to the server and retrieve the content (Note: now the question has been answered i have remove the reference to the actual site)

            // Parse the html document
            var document = new HtmlDocument(); // HTML Agility Pack
            document.LoadHtml(request.Data);

            // Get the required info
            var forumNode = document.DocumentNode.SelectSingleNode("//div[@id='breadcrumb']/a[@href='/Forum/ViewForum/1']");
            var topicNode = document.DocumentNode.SelectSingleNode("//div[@id='breadcrumb']/span");

            // Test if the info is valid
            if (forumNode == null || topicNode.InnerText != "Test Topic")
                throw new Exception();
        } catch {
            isValid = false;
            break;
        }
    }

    // Asset
    Assert.IsTrue(isValid);
}

此测试失败，因为显示错误的痕迹和/或标题。

我的ViewTopic操作方法中包含以下代码：

// Override the parent node title and url
SiteMap.CurrentNode.ParentNode.Title = topic.Forum.ForumName;
SiteMap.CurrentNode.ParentNode.Url = Url.GenerateUrl("ViewForum", new { id = topic.Forum.ForumID });

// Set the meta description
SiteMap.CurrentNode["MetaDescription"] = topic.Subject;

以及应用SiteMapTitle属性以将当前节点标题更改为主题的主题。

如果你能提供帮助，我真的很感激。感谢

Answer 1

我收到开发人员的回复说这是由于ASP.NET的限制。他希望通过完全隔离这个功能在版本4中删除它。在此之前，最好的解决方案是通过将其作为ViewData传递来覆盖标题。

编辑（以下是我提出的临时解决方案）：

创建以下SiteMapAttribute.cs文件：

public class SiteMapAttribute : ActionFilterAttribute {
    protected string TitlePropertyName { get; set; }
    protected string PageTitlePropertyName { get; set; }
    protected string MetaDescriptionPropertyName { get; set; }
    protected string MetaKeywordsPropertyName { get; set; }
    protected string ParentTitlePropertyName { get; set; }

    public SiteMapAttribute() {
    }

    public SiteMapAttribute(string titlePropertyName) {
        TitlePropertyName = titlePropertyName;
    }

    public SiteMapAttribute(string titlePropertyName, string pageTitlePropertyName, string metaDescriptionPropertyName, string metaKeywordsPropertyName)
        : this(titlePropertyName) {
        PageTitlePropertyName = pageTitlePropertyName;
        MetaDescriptionPropertyName = metaDescriptionPropertyName;
        MetaKeywordsPropertyName = metaKeywordsPropertyName;
    }

    public SiteMapAttribute(string titlePropertyName, string pageTitlePropertyName, string metaDescriptionPropertyName, string metaKeywordsPropertyName, string parentTitlePropertyName)
        : this(titlePropertyName, pageTitlePropertyName, metaDescriptionPropertyName, metaKeywordsPropertyName) {
        ParentTitlePropertyName = parentTitlePropertyName;
    }

    public override void OnActionExecuted(ActionExecutedContext filterContext) {
        if (filterContext.Result is ViewResult) {
            var result = (ViewResult)filterContext.Result;

            // Get the current node
            var currentNode = filterContext.Controller.GetCurrentSiteMapNode();

            // Make sure the node is found
            if (currentNode != null) {
                // Set the title and meta information (if applicable)
                if (!result.ViewData.ContainsKey("Title"))
                    result.ViewData["Title"] = Resolve(result, TitlePropertyName) ?? currentNode.Title;

                if (!result.ViewData.ContainsKey("PageTitle"))
                    result.ViewData["PageTitle"] = Resolve(result, PageTitlePropertyName) ?? (currentNode["PageTitle"] ?? currentNode.Title);

                if (!result.ViewData.ContainsKey("MetaDescription"))
                    result.ViewData["MetaDescription"] = Resolve(result, MetaDescriptionPropertyName) ?? currentNode["MetaDescription"];

                if (!result.ViewData.ContainsKey("MetaKeywords"))
                    result.ViewData["MetaKeywords"] = Resolve(result, MetaKeywordsPropertyName) ?? currentNode["MetaKeywords"];

                if (!result.ViewData.ContainsKey("ParentTitle"))
                    result.ViewData["ParentTitle"] = Resolve(result, ParentTitlePropertyName);
            }
        }
    }

    private string Resolve(ViewResult result, string propertyName) {
        if (string.IsNullOrEmpty(propertyName))
            return null;

        var target = ResolveTarget(result.ViewData.Model, propertyName);

        if (target == null)
            target = ResolveTarget(result.ViewData, propertyName);

        return target != null ? target.ToString() : null;
    }

    private object ResolveTarget(object target, string expression) {
        try {
            var parameter = Expression.Parameter(target.GetType(), "target");
            var lambdaExpression = DynamicExpression.ParseLambda(new[] { parameter }, null, "target." + expression);
            return lambdaExpression.Compile().DynamicInvoke(target);
        } catch {
            return null;
        }
    }
}

然后，您需要确保所有控制器都应用了此属性。在ASP.NET MVC 3中，这可以更简单，因为您可以将其注册为全局过滤器。

现在您需要修改您的母版页并说出如下内容：

<head>
    <title><%= ViewData["PageTitle"] %></title>
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
    <% if (ViewData["MetaDescription"] != null && !string.IsNullOrEmpty(ViewData["MetaDescription"].ToString())) { %>
        <meta name="Description" content="<%= ViewData["MetaDescription"] %>" />
    <% } %>
    <% if (ViewData["MetaKeywords"] != null && !string.IsNullOrEmpty(ViewData["MetaKeywords"].ToString())) { %>
        <meta name="Keywords" content="<%= ViewData["MetaKeywords"] %>" />
    <% } %>
</head>

现在要修补面包屑（SiteMapPath），我必须得到一点点hacky。首先，我创建了自己的帮手：

/// <summary>
/// MvcSiteMapHtmlHelper extension methods
/// </summary>
public static class SiteMapBreadcrumbExtensions {
    /// <summary>
    /// Source metadata
    /// </summary>
    private static Dictionary<string, object> SourceMetadata = new Dictionary<string, object> { { "HtmlHelper", typeof(SiteMapBreadcrumbExtensions).FullName } };

    /// <summary>
    /// Gets SiteMap path for the current request
    /// </summary>
    /// <param name="helper">MvcSiteMapHtmlHelper instance</param>
    /// <returns>SiteMap path for the current request</returns>
    public static MvcHtmlString SiteMapBreadcrumb(this MvcSiteMapHtmlHelper helper) {
        return SiteMapBreadcrumb(helper, null);
    }

    /// <summary>
    /// Gets SiteMap path for the current request
    /// </summary>
    /// <param name="helper">MvcSiteMapHtmlHelper instance</param>
    /// <param name="templateName">Name of the template.</param>
    /// <returns>SiteMap path for the current request</returns>
    public static MvcHtmlString SiteMapBreadcrumb(this MvcSiteMapHtmlHelper helper, string templateName) {
        var model = BuildModel(helper, helper.Provider.CurrentNode);

        return helper
            .CreateHtmlHelperForModel(model)
            .DisplayFor(m => model, templateName, new { Title = helper.HtmlHelper.ViewData["Title"], ParentTitle = helper.HtmlHelper.ViewData["ParentTitle"], ParentUrl = helper.HtmlHelper.ViewData["ParentUrl"] });
    }

    /// <summary>
    /// Builds the model.
    /// </summary>
    /// <param name="helper">The helper.</param>
    /// <param name="startingNode">The starting node.</param>
    /// <returns>The model.</returns>
    private static SiteMapPathHelperModel BuildModel(MvcSiteMapHtmlHelper helper, SiteMapNode startingNode) {
        // Build model
        var model = new SiteMapPathHelperModel();
        var node = startingNode;

        while (node != null) {
            var mvcNode = node as MvcSiteMapNode;

            // Check visibility
            var nodeVisible = true;

            if (mvcNode != null)
                nodeVisible = mvcNode.VisibilityProvider.IsVisible(node, HttpContext.Current, SourceMetadata);

            // Check ACL
            if (nodeVisible && node.IsAccessibleToUser(HttpContext.Current))
                model.Nodes.Add(SiteMapNodeModelMapper.MapToSiteMapNodeModel(node, mvcNode, SourceMetadata));

            node = node.ParentNode;
        }

        model.Nodes.Reverse();

        return model;
    }
}

这与内置的唯一区别在于它将ViewData传递给模板。最后我创建了2个DisplayTemplates：

SiteMapNodeModel.axcx：

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<MvcSiteMapProvider.Web.Html.Models.SiteMapNodeModel>" %>
<% if (Model.IsCurrentNode) { %>
    <span class="orange-text"><%= (ViewData["Title"] ?? Model.Title).ToString() %></span>
<% } else if ((bool)ViewData["IsParent"]) { %>
    <a href="<%= (ViewData["ParentUrl"] ?? Model.Url).ToString() %>"><%= (ViewData["ParentTitle"] ?? Model.Title).ToString() %></a>
<% } else { %>
    <a href="<%= Model.Url %>"><%= Model.Title %></a>
<% } %>

和SiteMapPathHelperModel.ascx：

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<MvcSiteMapProvider.Web.Html.Models.SiteMapPathHelperModel>" %>
<% for (var i = 0; i < Model.Nodes.Count(); i++) { %>
    <%= Html.DisplayFor(m => Model.Nodes[i], new { isParent = Model.Count() - 2 == i }) %>
    <% if (Model.Nodes[i] != Model.Last()) { %>
        &gt;
    <% } %>
<% } %>

您现在可以在视图中说出以下内容以显示被覆盖的痕迹：

<%= Html.MvcSiteMap().SiteMapBreadcrumb() %>

现在完成了这项工作，您只需要知道如何覆盖特定操作的元/面包屑信息。最简单的方法是覆盖特定操作的SiteMapAttribute，例如

[SiteMap("Subject", "Subject", "Subject", "", "Forum.ForumName")]
public ActionResult ViewTopic(int id, [DefaultValue(1)] int page) {
}

这将相应地设置标题，页面标题，元信息和父标题。如果你希望标题绑定到比单个属性更复杂的东西，你可以在action方法中设置这个，如下所示：

ViewData["Title"] = "My Title - " + DateTime.UtcNow.ToShortDateString();

希望这有帮助。

ASP.NET MVC站点地图提供程序在重负载下中断

1 个答案:

ASP.NET MVC站点地​​图提供程序在重负载下中断

1 个答案:

ASP.NET MVC站点地图提供程序在重负载下中断