Question

我有这个问题。

  levelnumber = (from b in bv.baLevels
                 where b.ba_Level_Code == ("0" + SqlFunctions.StringConvert((double)cl.Level_Num.Value)) && b.isActive == 1
                 select (b.ba_Level_Code + " - " + b.ba_Level_Desc)).FirstOrDefault(),

我的问题是b.ba_Level_Code是字符串。

cl.Level_Num是Int。

baLevels表我有这个ba_Level_code值有008

但是cl是BaCodeLibrary表，这个cl.Level_Num有8个

如果我使用硬编码值进行查询

 levelnumber = (from b in bv.baLevels
                where b.ba_Level_Code == "008" && b.isActive == 1
                select (b.ba_Level_Code + " - " + b.ba_Level_Desc)).FirstOrDefault(),

如何显示008？ cl.Level_Num我得到了8.我需要将该值更改为008。

由于

Answer 1

我无法在LINQ to Enties中看到这样做的好方法。假设您无法修改ba_Level_Code列的数据类型，我认为您最好的选择是向该表添加持久性computed column，对其进行索引，并在查询中使用该列。

例如，如果您定义了一列

ba_Level_Code_Int as (case when isnumeric(ba_Level_Code)= 1 then cast(ba_Level_Code as int) end) persisted

那么你的LINQ查询可能是

levelnumber = (from b in bv.baLevels   
               where b.ba_Level_Code_Int == cl.Level_Num.Value && b.isActive == 1   
               select (b.ba_Level_Code + " - " + b.ba_Level_Desc)).FirstOrDefault();

Answer 2

您可以使用string.Format指定将`cl.Level_Num'转换为具有最小位数的字符串：

string.Format("{0:D3}", cl.Level_Num.Value) // would ouput "008" value 8

因此：

levelnumber = (from b in bv.baLevels
               where b.ba_Level_Code == string.Format("{0:D3}", cl.Level_Num.Value) && b.isActive == 1
               select (b.ba_Level_Code + " - " + b.ba_Level_Desc)).FirstOrDefault()

Linq中的字符（字符串）编号与数字比较

2 个答案: