多列不区分大小写的组 [英] Case insensitive group on multiple columns

问题描述

无论如何，有没有做类似的事情的LINQ2SQL查询:

Is there anyway to do a LINQ2SQL query doing something similar to this:

var result = source.GroupBy(a => new { a.Column1, a.Column2 });

或

var result = from s in source
             group s by new { s.Column1, s.Column2 } into c
             select new { Column1 = c.Key.Column1, Column2 = c.Key.Column2 };

但是忽略分组列内容的大小写吗?

but with ignoring the case of the contents of the grouped columns?

推荐答案

您可以将StringComparer.InvariantCultureIgnoreCase传递给GroupBy扩展方法.

You can pass StringComparer.InvariantCultureIgnoreCase to the GroupBy extension method.

var result = source.GroupBy(a => new { a.Column1, a.Column2 }, 
                StringComparer.InvariantCultureIgnoreCase);

或者您也可以按照 Hamlet Hakobyan 的建议在每个字段上使用ToUpperInvariant.我建议使用ToUpperInvariant或ToUpper而不是ToLower或ToLowerInvariant，因为它已针对程序比较进行了优化.

Or you can use ToUpperInvariant on each field as suggested by Hamlet Hakobyan on comment. I recommend ToUpperInvariant or ToUpper rather than ToLower or ToLowerInvariant because it is optimized for programmatic comparison purpose.

这篇关于多列不区分大小写的组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！