sharepoint 查找 Loginuser在item 中的权限

                    using (SPSite site = new SPSite(approver.ParentTask.WFContext.Web.Site.ID))
                    {
                        using (SPWeb currentWeb = site.OpenWeb(approver.ParentTask.WFContext.Web.ID))
                        {
                               SPList currentlist = currentWeb.Lists[this.ListID];

                                SPListItem superItem = currentlist.Items.GetItemById(this.ItemID);
                                                                      
                                       SPRoleAssignmentCollection raCollection = superItem.RoleAssignments;
                                        SPRoleDefinitionBindingCollection roleDefinitionCollect = new SPRoleDefinitionBindingCollection();
                                        for (int i = 0; i < raCollection.Count;i++ )
                                        {
                                            if (raCollection[i].Member.LoginName == userID)// 判断用户是否与指定用户一样。
                                            {
                                                roleDefinitionCollect = raCollection[i].RoleDefinitionBindings;
                                                break;
                                            }
                                        }

 

                                         if (roleDefinitionCollect != null && roleDefinitionCollect.Count > 0)
                                        {
                                            foreach (SPRoleDefinition useritemrole in roleDefinitionCollect)
                                            {
                                               //循环输出权限  如 读取 查看，设计，参与者         

                                             }
                                        }
                                        }
                    }