如何获得最大数量？ [英] How to get the biggest number?

问题描述

如何获得最大的数字？

i我试图从我的数据库中的一个字段中获取最大数字，但这很奇怪，因为我使用这个简单的代码

How get the biggest number?
i am trying to get the biggest number from a field in my database but is it strange because i use this simple code

amenitiesExcel = dc.Hotel_Meals_TBLs.Select(Convert.ToInt32(a => a.CodeNumber)).Max();

当我编译查询时，我收到此错误：

and when i compile the query i receive this error:

Error   370 The type arguments for method 'System.Linq.Queryable.Select<TSource,TResult>(System.Linq.IQueryable<TSource>, System.Linq.Expressions.Expression<System.Func<TSource,TResult>>)' cannot be inferred from the usage. Try specifying the type arguments explicitly.

...数据库中的字段CodeNumber是Nvarchar数据类型，然后只填充数字，我需要存储最大的在这个领域的数字，你有任何想法或建议如何在这种情况下获得最大的数字



非常感谢你的支持。



干杯

...the field "CodeNumber" in the database is a Nvarchar Datatype then is filled only with number and i need to store the biggest number in this field ,do you have any idea or suggestion how i can get the biggest number in this case

Thanks so much for the support.

Cheers

推荐答案

你应该试试这个：

You should try this:

amenitiesExcel = dc.Hotel_Meals_TBLs.Max(a => Convert.ToInt32(a.CodeNumber));

或

or

amenitiesExcel = dc.Hotel_Meals_TBLs.Max(a => int.Parse(a.CodeNumber));

您不需要转换为int。只需更改您的查询，如下所示

You don''t need to Convert to int. Just change your Query like below

amenitiesExcel = dc.Hotel_Meals_TBLs.Max(a => a.CodeNumber);

希望这有帮助

Hope this helps

试试这个

Try this

int amenitiesExcel = 0;
amenitiesExcel = dc.Hotel_Meals_TBLs.Max(a => (int?)a.CodeNumber)?? 0;

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