Coding获取站点中被任何用户标记为I like it的项

最近，我做了一个在SharePoint2010中查询出所有被任何用户tag为I like it的content。在开发的过程中遇到两个问题：第一个是用户权限的提升，虽然模拟了SharePoint\system账号，但是创建的SocialTagManager对象的IsSocialAdmin属性始终是false.只有在User Profile Service Application中将当前用户设置为Administrator才查询出了所有数据。但是其他用户登录，不可能给其开放Administrator的权限。因此，要查询出所有的I Like it，还是必须从提升权限下手。遇到的第二个问题就是，如果查询出一个Uri被tag为I like it多少次？

后来，经过研究前辈们的提升权限的方法。总算发现了怎么把当前上下文提升为管理员账号。并查询出一个Uri被tag为 I like it的次数。 我将实现的方法Share出来，希望对跟我遇到同样问题的朋友们能有所帮助。

下面的代码是关于如何将当前上下文临时提升为管理员权限,注意HttpContext.Current必须在RunWithElevatedPrivileges的委托方法里面设置为NULL。

SPSecurity.RunWithElevatedPrivileges(delegate
        {
            System.Web.HttpContext tempCtx = System.Web.HttpContext.Current;
            //emulate a system account 
            using (SPSite site = new SPSite(SPContext.Current.Web.Site.Url, SPContext.Current.Web.Site.SystemAccount.UserToken))
            {
            //remove current user's context
                System.Web.HttpContext.Current = null;
            }
        }

　　

而对于第二个问题（查询I like it个数的），使用SocialTagManager.GetTerms()方法，传入要查询的Url，方法会返回所有给url上标记的SocialTerm。使用Linq找到I like it的SocialTerm。它有一个Count的属性，这个属性在MSDN上没有描述它的用途。通过测试，我发现它就是当前I like it被标记的个数。如果用户上下文没有提升到System Account的权限，那么找出来的值就始终是1或者0.

下面是所有的相关的代码：

 public partial class SocialTaggedUrlListsWebPartUserControl : UserControl
    {
        /// <summary>
        /// Get or set a value that specifies the maximum number of the results
        /// </summary>
        public int Maxinum
        {
            get;
            set;
        }

        /// <summary>
        /// Get or set a value that specifes the SocialTag Name which is used to search url.
        /// </summary>
        public string SocialTagName
        {
            get;
            set;
        }

        private class TaggedItem
        {
            public TaggedItem(string title, string url, string iconUrl, int tagPeopleNum)
            {
                this.Title = title;
                this.Url = url;
                this.IconUrl = iconUrl;
                this.TagPeopleNum = tagPeopleNum;
            }

            /// <summary>
            /// Get or set the Title property of TaggedItem object
            /// </summary>
            public String Title
            {
                get;
                set;
            }

            /// <summary>
            /// Get or set the Url property of TaggedItem object
            /// </summary>
            public string Url
            {
                get;
                set;
            }

            /// <summary>
            /// Get or set the  IconUrl property
            /// </summary>
            public string IconUrl
            {
                get;
                set;
            }

            /// <summary>
            /// Get or set the TagPeopleNum property ,which is used to specify the number of poeple who tagged the url with the specified SocialTag.
            /// </summary>
            public int TagPeopleNum
            {
                get;
                set;
            }
        }

        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected override void Render(HtmlTextWriter writer)
        {
            base.Render(writer);
            SPSecurity.RunWithElevatedPrivileges(delegate
            {
                System.Web.HttpContext tempCtx = System.Web.HttpContext.Current;
                try
                {
                    //emulate a system account 
                    using (SPSite site = new SPSite(SPContext.Current.Web.Site.Url, SPContext.Current.Web.Site.SystemAccount.UserToken))
                    {
                        string rootUrl = SPContext.Current.Site.Url;

                        //remove current user's context
                        System.Web.HttpContext.Current = null;

                        SPServiceContext serverContext = SPServiceContext.GetContext(site);
                        SocialTagManager socialTagManager = new SocialTagManager(serverContext);
                        //get a term named 'I like it'
                        TaxonomySession taxonomySession = new TaxonomySession(site);
                        Term term = taxonomySession.GetTerms(SocialTagName, true).First();
                        if (term != null)
                        {
                            //get an array of all urls owned by any user with the specified Term, and the scope is current site.
                            SocialUrl[] socialUrls = FilterUrl(socialTagManager.GetAllUrls(term), rootUrl);
                            if (socialUrls.Length == 0)
                            {
                                writer.Write("There are no available items tagged with \"" + this.SocialTagName + "\"");
                                return;
                            }
                            using (SPWeb web = site.OpenWeb())
                            {
                                IList<TaggedItem> taggedItems = BuilderTaggedItem(web, socialTagManager, socialUrls, rootUrl);

                                if (taggedItems.Count == 0)
                                {
                                    return;
                                }
                                //sort list by the Count property

                                writer.Write("<style>#topResultsTab td{ ");
                                writer.Write("     height:32px; ");
                                writer.Write("     border-bottom:1px dashed rgb(220,220,220); ");
                                writer.Write("} </style>");

                                writer.Write("      <div class='item link-item' style='padding-left: 5px; border-bottom: 1px rgb(235,235,235) dashed;padding-right: 5px;'>");

                                writer.Write("<table id=\"topResultsTab\" style=\"100%\">");


                                foreach (TaggedItem taggedItem in taggedItems)
                                {
                                    writer.Write("<tr>");

                                    writer.Write("<td style='18px; vertical-align: bottom; position: relative;'>");
                                    writer.Write(string.Format("<img src='{0}' width='16px' height='16px'/> ", GlobalVariables.SYS_IMG_RELATIVE_PATH + taggedItem.IconUrl));
                                    writer.Write("</td>");

                                    writer.Write("<td  style='font-weight: bold;font-size: 14px; vertical-align: bottom; position: relative;'> ");
                                    writer.Write(string.Format("<a style='font-size: 14px' href='{0}' >{1}</a>", taggedItem.Url, taggedItem.Title));
                                    writer.Write("</td>");

                                    writer.Write("<td style='100px;vertical-align: bottom;color:#666;  position: relative; text-align: left;'>");
                                    writer.Write(string.Format("<img src='{0}allusr.gif' alt='People' width='16px' height='16px' style='vertical-align: bottom;position: relative; '/>", GlobalVariables.SYS_IMG_RELATIVE_PATH));
                                    writer.Write(string.Format("<span >Tagged by <a href='javascript:;' class='people' msItemUrl='{0}'> {1} </a></span>", taggedItem.Url, taggedItem.TagPeopleNum));
                                    writer.Write("</td>");

                                    writer.Write("</tr>");
                                }
                            }
                        }
                        else
                        {
                            writer.Write("There are no available items tagged with \"" + this.SocialTagName + "\"");
                        }
                        writer.Write("</table>");
                        writer.Write("</div>");
                    }
                }
                catch (Exception ex)
                {
                    writer.Write(ex.Message);
                }
                finally
                {
                    System.Web.HttpContext.Current = tempCtx;
                }
            });
        }



        private SocialUrl[] FilterUrl(SocialUrl[] socialUrls, string filterUrl)
        {
            IList<SocialUrl> filteredUrls = new List<SocialUrl>();
            int index = 0;
            for (int i = 0; i < socialUrls.Length; i++)
            {
                if (socialUrls[i].Url.AbsoluteUri.StartsWith(filterUrl))
                {
                    filteredUrls.Add(socialUrls[i]);
                    index++;
                }
            }
            return filteredUrls.ToArray();
        }


        private IList<TaggedItem> BuilderTaggedItem(SPWeb web, SocialTagManager socialTagManager, SocialUrl[] socialUrls, string rootUrl)
        {
            //retrieve the number of terms associated with a specified url by the specified tag name .
            IList<object> socialTagList = new List<object>();
            for (int i = 0; i < socialUrls.Length; i++)
            {
                IList<SocialTerm> list = socialTagManager.GetTerms(socialUrls[i].Url, 100).Where(v => v.Term.Name.Equals(SocialTagName, StringComparison.CurrentCultureIgnoreCase)).ToList();
                socialTagList.Add(new { Url = socialUrls[i], Count = list.Count > 0 ? list[0].Count : 0, ModefiedData = socialUrls[i].LastModifiedTime });
            }

            socialTagList = socialTagList.OrderByDescending(v => v.GetType().GetProperty("Count").GetValue(v, null)).ToList();

            IList<TaggedItem> taggedItems = new List<TaggedItem>();

            for (int i = 0; i < socialTagList.Count; i++)
            {
                TaggedItem taggedItem = null;
                object obj = null;
                string icon = string.Empty;
                SocialUrl socialUrl = socialTagList[i].GetType().GetProperty("Url").GetValue(socialTagList[i], null) as SocialUrl;
                int pepleNum = Convert.ToInt32(socialTagList[i].GetType().GetProperty("Count").GetValue(socialTagList[i], null));
 　　　　　　　　  SPWeb correctWeb= GetWeb(web, socialUrl.Url.AbsoluteUri);

                　　 try
                　 　{
                     obj = correctWeb.GetObject(socialUrl.Url.AbsoluteUri);
                　 　}
                　　 catch
                　　 {
                    　　 continue;
                　 　}

                if (obj is SPListItem)
                {
                    SPListItem spListItem = obj as SPListItem;
                    icon = Microsoft.SharePoint.Utilities.SPUtility.MapToIcon(web, socialUrl.Title, spListItem.ProgId);
                    taggedItem = new TaggedItem(spListItem.Title, socialUrl.Url.AbsoluteUri, icon, pepleNum);
                }
                else if (obj is SPFile)
                {
                    SPFile spFile = obj as SPFile;
                    taggedItem = new TaggedItem(socialUrl.Title, socialUrl.Url.AbsoluteUri, spFile.IconUrl, pepleNum);
                }
                else if (obj is SPFolder)
                {
                    SPFolder spFolder = obj as SPFolder;
                    　　string title = string.IsNullOrEmpty(spFolder.Name) ? socialUrl.Title : spFolder.Name;

                    　　if ((socialUrl.Url.AbsoluteUri.EndsWith("/") ? socialUrl.Url.AbsoluteUri.Remove(socialUrl.Url.AbsoluteUri.Length - 1, 1) : socialUrl.Url.AbsoluteUri)
                        .Equals(
                        correctWeb.Url.EndsWith("/") ? correctWeb.Url.Remove(correctWeb.Url.Length - 1, 1) : correctWeb.Url))
                    　　{
                        　　title = string.IsNullOrEmpty(correctWeb.Title) ? "" : (correctWeb.Title+"-") + title;
                    　　}

                    　　icon = Microsoft.SharePoint.Utilities.SPUtility.MapToIcon(web, string.Empty, spFolder.ProgID);
                    　　taggedItem = new TaggedItem(title, socialUrl.Url.AbsoluteUri, "FOLDER.GIF", pepleNum);
                }
                else
                {
                    taggedItem = new TaggedItem(socialUrl.Title, socialUrl.Url.AbsoluteUri, string.Empty, pepleNum);

                }
                if (string.IsNullOrEmpty(taggedItem.IconUrl))
                {
                    taggedItem.IconUrl = "icgen.gif";
                }
                taggedItems.Add(taggedItem);
                if (taggedItems.Count >= this.Maxinum)
                {
                    break;
                }
            }
            return taggedItems;
        }

    }