LINQ to Entities 无法识别方法 \'System.String ToShortDateString()\' 方法答案

【问题标题】：LINQ to Entities does not recognize the method 'System.String ToShortDateString()' methodLINQ to Entities 无法识别方法 \'System.String ToShortDateString()\' 方法
【发布时间】：2022-10-07 14:08:04
【问题描述】：

在我的 asp.net MVC 应用程序中，查看模型我创建了一个属性类型string 来显示date。

但在模型中，该属性存储为DateTime，因此在我的查询中，我通过将日期时间转换为ToShortDateString 来分配它。

因为存储的值是与表中的日期时间。(example2022-10-06 11:32:48.917)

但在视图中，我只想显示日期。

运行此查询时出现此错误

LINQ to Entities does not recognize the method \'System.String ToShortDateString()\' method, 
and this method cannot be translated into a store expression.\'

只想知道如何只将日期传递给这种查询的视图。

这是我当前的代码。

var TaskMain = (from t in db.TaskMain
                join service in db.Services on t.Service_Id equals service.Id
                join category in db.ServiceCategory on service.Service_Category_Id equals category.Id
                join branch in db.Branch on t.Current_Branch_Id equals branch.Id
                join emp in db.Employee on t.Task_Assigned_Emp_Id equals emp.Id
                where t.Id == id
                select new TaskDetails
                {
                  Id = t.Id,
                  Note = t.Note,
                  Current_Step= t.Task_Step_Id,
                  Service_Category = category.Service_Category_Name,
                  Service_End_Date = t.Service_End_Date.ToShortDateString(),
                  Service_Price = t.Service_Price,
                  Service_Start_Date = t.CreatedDate.ToShortDateString(),
                  Task_Created_Branch = branch.BranchName,
                  Service_Name = service.Service_NameEng
                }).ToList();

标签： c# asp.net asp.net-mvc entity-framework linq

【解决方案1】：

ToShortDateString() 不是数据库识别的东西。因此，您需要使用.AsEnumerable()（或.ToList()）将转换带到客户端。试试这个代码。

var TaskMain = (from t in db.TaskMain
                join service in db.Services on t.Service_Id equals service.Id
                join category in db.ServiceCategory on service.Service_Category_Id equals category.Id
                join branch in db.Branch on t.Current_Branch_Id equals branch.Id
                join emp in db.Employee on t.Task_Assigned_Emp_Id equals emp.Id
                where t.Id == id
                select new
                {
                  Id = t.Id,
                  Note = t.Note,
                  Current_Step= t.Task_Step_Id,
                  Service_Category_Name = category.Service_Category_Name,
                  Service_End_Date = t.Service_End_Date,
                  Service_Price = t.Service_Price,
                  CreatedDate = t.CreatedDate,
                  BranchName = branch.BranchName,
                  Service_NameEng = service.Service_NameEng
                }).AsEnumerable()
                .Select(s => new TaskDetails
                {
                  Id = t.Id,
                  Note = t.Note,
                  Current_Step= t.Task_Step_Id,
                  Service_Category = category.Service_Category_Name,
                  Service_End_Date = t.Service_End_Date.ToShortDateString(),
                  Service_Price = t.Service_Price,
                  Service_Start_Date = t.CreatedDate.ToShortDateString(),
                  Task_Created_Branch = branch.BranchName,
                  Service_Name = service.Service_NameEng
                }).ToList();

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