asp.net-mvc-3 – 方法“OrderBy”必须在方法“跳过”异常之前调
发布时间:2020-12-15 20:22:26 所属栏目:asp.Net 来源:网络整理
导读:我试图使用MvcjQgrid实现jQgrid,我得到这个异常. System.NotSupportedException was unhandled by user code Message=The method 'Skip' is only supported for sorted input in LINQ to Entities. The method 'OrderBy' must be called before the method '
我试图使用MvcjQgrid实现jQgrid,我得到这个异常.
System.NotSupportedException was unhandled by user code Message=The method 'Skip' is only supported for sorted input in LINQ to Entities. The method 'OrderBy' must be called before the method 'Skip'. 虽然OrdeyBy在Skip方法之前使用为什么会生成异常?怎么解决? 我在控制器中遇到了异常: public ActionResult GridDataBasic(GridSettings gridSettings) { var jobdescription = sm.GetJobDescription(gridSettings); var totalJobDescription = sm.CountJobDescription(gridSettings); var jsonData = new { total = totalJobDescription / gridSettings.PageSize + 1,page = gridSettings.PageIndex,records = totalJobDescription,rows = ( from j in jobdescription select new { id = j.JobDescriptionID,cell = new[] { j.JobDescriptionID.ToString(),j.JobTitle,j.JobType.JobTypeName,j.JobPriority.JobPriorityName,j.JobType.Rate.ToString(),j.CreationDate.ToShortDateString(),j.JobDeadline.ToShortDateString(),} }).ToArray() }; return Json(jsonData,JsonRequestBehavior.AllowGet); } GetJobDescription方法和CountJobDescription方法 public int CountJobDescription(GridSettings gridSettings) { var jobdescription = _dataContext.JobDescriptions.AsQueryable(); if (gridSettings.IsSearch) { jobdescription = gridSettings.Where.rules.Aggregate(jobdescription,FilterJobDescription); } return jobdescription.Count(); } public IQueryable<JobDescription> GetJobDescription(GridSettings gridSettings) { var jobdescription = orderJobDescription(_dataContext.JobDescriptions.AsQueryable(),gridSettings.SortColumn,gridSettings.SortOrder); if (gridSettings.IsSearch) { jobdescription = gridSettings.Where.rules.Aggregate(jobdescription,FilterJobDescription); } return jobdescription.Skip((gridSettings.PageIndex - 1) * gridSettings.PageSize).Take(gridSettings.PageSize); } 最后FilterJobDescription和OrderJobDescription private static IQueryable<JobDescription> FilterJobDescription(IQueryable<JobDescription> jobdescriptions,Rule rule) { if (rule.field == "JobDescriptionID") { int result; if (!int.TryParse(rule.data,out result)) return jobdescriptions; return jobdescriptions.Where(j => j.JobDescriptionID == Convert.ToInt32(rule.data)); } // Similar Statements return jobdescriptions; } private IQueryable<JobDescription> orderJobDescription(IQueryable<JobDescription> jobdescriptions,string sortColumn,string sortOrder) { if (sortColumn == "JobDescriptionID") return (sortOrder == "desc") ? jobdescriptions.OrderByDescending(j => j.JobDescriptionID) : jobdescriptions.OrderBy(j => j.JobDescriptionID); return jobdescriptions; } 解决方法
异常意味着如果您应用“跳过”,则您总是需要排序输入,也就是在用户不点击列进行排序的情况下.我可以想象,在用户甚至可以点击列标题之前首次打开网格视图时,没有指定排序列.为了抓住这种情况,我建议在没有给出其他排序条件时定义一些你想要的默认排序,例如:
switch (sortColumn) { case "JobDescriptionID": return (sortOrder == "desc") ? jobdescriptions.OrderByDescending(j => j.JobDescriptionID) : jobdescriptions.OrderBy(j => j.JobDescriptionID); case "JobDescriptionTitle": return (sortOrder == "desc") ? jobdescriptions.OrderByDescending(j => j.JobDescriptionTitle) : jobdescriptions.OrderBy(j => j.JobDescriptionTitle); // etc. default: return jobdescriptions.OrderBy(j => j.JobDescriptionID); } 编辑 关于您的后续问题根据您的评论:您不能在LINQ to Entities查询中使用ToString().而下一个问题是您无法在查询中创建一个字符串数组.我建议从数据库中加载其原始类型的数据,然后将其转换为内存中的字符串(和字符串数组): rows = (from j in jobdescription select new { JobDescriptionID = j.JobDescriptionID,JobTitle = j.JobTitle,JobTypeName = j.JobType.JobTypeName,JobPriorityName = j.JobPriority.JobPriorityName,Rate = j.JobType.Rate,CreationDate = j.CreationDate,JobDeadline = j.JobDeadline }) .AsEnumerable() // DB query runs here,the rest is in memory .Select(a => new { id = a.JobDescriptionID,cell = new[] { a.JobDescriptionID.ToString(),a.JobTitle,a.JobTypeName,a.JobPriorityName,a.Rate.ToString(),a.CreationDate.ToShortDateString(),a.JobDeadline.ToShortDateString() } }) .ToArray() (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |
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