如何在linq中创建具有多个条件的orselect [英] how to create orselect with multi condition in linq

问题描述

嗨
我想要选择数据女巫，例如sensor =sen或Area =aa

i写下这段代码：

Hi I want select data witch for example sensor="sen" or Area="aa"
i write this code:

var listsegment2 = from ls1 in SMDB.SegmentInfos
where (ls1.Area == area || string.IsNullOrEmpty(area)) && (ls1.Sensor == sen||string.IsNullOrEmpty(sen)) && (ls1.System == sys || string.IsNullOrEmpty(sys)) && (ls1.Jbo == jbo || string.IsNullOrEmpty(jbo))
select new
{}

但此代码返回和条件结果

help我要更正代码，请

but this code return andconditions result
help me to correct code,please

推荐答案

如果我正确理解了这个问题，你已经使用了&&你应该在哪里使用||



所以这样的事情：

If I understood the question correctly, you have used && where you should've used ||

So something like this:

var listsegment2 = from ls1 in SMDB.SegmentInfos
                   where (  (ls1.Area == area || string.IsNullOrEmpty(area)) 
                         || (ls1.Sensor == sen || string.IsNullOrEmpty(sen))
                   )
                   && (ls1.System == sys || string.IsNullOrEmpty(sys)) 
                   && (ls1.Jbo == jbo || string.IsNullOrEmpty(jbo))
select new
{}

如果传感器和区域可以是sen或aa ，然后只需使用OR =||



string.Equals是比较字符串的好方法。

If Sensor and Area can be "sen" or "aa", then just use OR = "||"

string.Equals is a great method to compare strings.

string sensor = "sen";
string area = "aa";
string system = "sys";

var listSegment2 = from ls1 in SMDB.SegmentInfos
                   where string.Equals(ls1.Area, area, StringComparison.InvariantCultureIgnoreCase)
                   || string.Equals(ls1.Sensor, sen, StringComparison.InvariantCultureIgnoreCase)
                   || string.Equals(ls1.System, system, StringComparison.InvariantCultureIgnoreCase)
                   select ls1;

foreach (var segment in listSegment2)
{
  Console.WriteLine("Segment - Area:" + segment.Area + ", Sensor:" + segment.Sensor);
}

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