LINQ to Entities无法识别方法'System.DateTime Parse（System.String）'方法，并且此方法无法转换为存储表达式。 [英] LINQ to Entities does not recognize the method 'System.DateTime Parse(System.String)' method, and this method cannot be translated into a store expression.

问题描述

嗨

我得到一个错误说：



LINQ to Entities无法识别方法'System.DateTime Parse（System。 String）'方法，这个方法无法翻译成商店表达式。



这是我各自的代码

Hi
im getting an error saying :

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

this is my respective code

Quote：

DateTime currenteDate = DateTime.Now.Date;

DateTime EndDate = DateTime.Now.Date .AddDays（3）;

ViewBag.TopRecenteFiles = db.Files.Where（y => DateTime.Parse（y.DueDate）> = currenteDate&& DateTime.Parse（y。 DueDate）< = EndDate& y.UserID == user.ID）。ToList（）。Take（7）;

DateTime currenteDate = DateTime.Now.Date;
DateTime EndDate = DateTime.Now.Date.AddDays(3);
ViewBag.TopRecenteFiles = db.Files.Where(y => DateTime.Parse(y.DueDate) >= currenteDate && DateTime.Parse(y.DueDate) <= EndDate && y.UserID == user.ID).ToList().Take(7);

所以任何人都可以帮助我



提前感谢

so can any one help me out

thanks in advance

推荐答案

好吧，这看起来非常简单：

Well, that seems pretty straightforward:

// Note the changes from your code here
DateTime currentDate = DateTime.Today;
DateTime endDate = currentDate.AddDays(3);
DateTime dueDate = db.Files.Where(y => (y.DueDate >= currentDate) && (y.DueDate <= endDate) && (y.UserID == user.ID)).ToList().Take(7);

但是，如果我怀疑的话，File对象的DueDate属性不是DateTime而是字符串（由您编写的代码建议），我担心您无法在单个Linq表达式中执行此操作。你将不得不诉诸一个普通的旧foreach循环。类似于：

However, if, like I suspect, the DueDate property of the File object is not a DateTime but a string (as suggested by the code you wrote), I'm afraid you won't be able to do it in a single Linq expression. You will have to resort to a plain old foreach loop. Something like:

DateTime currentDate = DateTime.Today;
DateTime endDate = currentDate.AddDays(3);
List<File> files = new List<File>();
foreach (File file in db.Files) {
   DateTime dueDate = DateTime.Parse(file.DueDate);
   if ((dueDate >= currentDate) && (dueDate <= endDate) && (file.UserId == user.ID)) {
      files.Add(file);
   }
}
// Here you have you File collection.
files = files.Take(7);

结论：当你有DateTime值时，使用DateTime类型，而不是字符串。

Conclusion: when you have DateTime values, use the DateTime type, not the string one.

这篇关于LINQ to Entities无法识别方法'System.DateTime Parse（System.String）'方法，并且此方法无法转换为存储表达式。的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！