Linq不等于(！=)条件

本文介绍了Linq不等于(！=)条件的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

大家好， 我在使用不等于(！=)条件的lambda(或linq)中遇到问题. 这是我的代码:

Hi guys, I have a problem in lambda(or linq) using not equal(!=) condition. Here''s my code:

IEnumerable<DataRow> ToUpload = dtTable.Select().Where(o => o[0] != dtUploadedIDs.Select().Where(p => (string)p[1] == sTableName).Select(q => q[0]));

dtTable看起来像这样:

dtTable looks like this:

-------------------- | IndexID | blabla -------------------- | 1 | asd | 2 | rtr --------------------

和dtUploadedIDs像这样:

and dtUploadedIDs is like this:

--------------------- | IndexID | TableName --------------------- | 1 | asd ---------------------

我想删除dtTable中IndexID等于dtUploadedIDs索引ID的所有行. 它们都在DataTable中. 请帮帮我. 在此先感谢您.

I want to remove all rows in dtTable whose IndexID is equal to dtUploadedIDs Index ID. They are both in DataTable. Please help me. Thanks in advance.

推荐答案

我将解决方案分为两个变量，以便更加清楚地说明， 首先，让我们获取所有ID(我想它是int类型，而不是字符串或其他任何类型): I''ve split my solution into two variables to be more clear, First thing, lets get all ids (I suppose it is type int, not string or any other): var allUploaded = dtUploadedIDs.Select().Select( p => ( int )p[ 0 ] );

拥有所有ID后，我们可以检查ToUpload表中的ID是否等于其中任何一个:

After we have all ids we can check whether our id from ToUpload table equals to any of them:

var ToUpload = dtTable.Select().Where( o => !allUploaded.Contains( ( int )o[ 0 ] ) );

而已.您可以根据需要将它们组合为单个表达式.

That''s it. You can combine them in single expression if you wish.

尝试此LINQ查询 Try this LINQ query // Select Distinct and Index ids that are only found in dtTable var indexIDs =(from row1 in dtTable.AsEnumerable() select new { indexID1 = row1.Field<string>("IndexID"), }).Distinct.Except(from row2 in dtUploadedIDs.AsEnumerable() select new { indexID2 = row2.Field<string>("IndexID") })); // Select the record based on the IndexId results var toUpload = (from row1 in dtTable.AsEnumerable() select new { indexID = row1.Field<string>("IndexID"), blabla = row1.Field<string>("blabla") }).where(r=> r.indexIDs.Contains(indexID)));

有关更多信息，请参见 101个LINQ示例:设置运算符[不同且不相同] [ ^ ] 在DataView中查询DataRowView集合 [ ^ ]

For more info look 101 LINQ Samples: Set Operators [ Distinct and Except ][^] Querying the DataRowView Collection in a DataView[^]