Question

我有一个字符串数组项目＆amp;一个数据库对象列表，我想从中做一个选择查询

List<string> target_terms = new List<string> { "car", "mechanic" }

if (isNotExactPhrase)
{
    List<int> _tagIds = (from item in dbContext.Tags
                    where target_terms.Any(w => item.TagName.Contains(w))
                    select item.TagId).ToList();
}

我想要所有带有数组的标签

我必须使用2个选项我要检查标记名包含任何关键字＆amp; 如果搜索是精确短语，那么我想检查任何Tagname ==任何关键字

但对于此查询，我收到错误

本地序列不能用于查询的LINQ to SQL实现除Contains运算符之外的运算符。

如何解决这个问题？

Answer 1

尝试此查询

var _tagIds = (from item in dbContext.Tags
                    where keywords.contains(item.TagName)
                    select item.TagId).ToList();

没有直接的等价物，但有些方法的工作方式相似，具体取决于模式。

string.Contains（＆＃34; pattern＆＃34;）相当于LIKE＆＃39;％pattern％＆＃39;

string.StartsWith（＆＃34; pattern＆＃34;）相当于LIKE＆＃39; pattern％＆＃39;

string.EndsWith（＆＃34; pattern＆＃34;）相当于LIKE＆＃39;％pattern＆＃39;

Answer 2

After hitting this problem a multitude of times, I created a nuget package that solves this common issue.

Using NinjaNye.SearchExtensions you can do the following:

var _tagIds = dbContext.Tags.Search(t => t.TagName)
                            .Containing(keywords)
                            .Select(t => t.TagId)
                            .ToList();

If you needed to you could also search against multiple properties and return records where a match was found in either property.

var _tagIds = dbContext.Tags.Search(t => t.TagName, t => t.Description)
                            .Containing(keywords)
                            .Select(t => t.TagId)
                            .ToList();

Hope this helps

Answer 3

尝试将Any替换为contains

List<int> _tagIds = (from item in dbContext.Tags
                    where target_terms.Contains(w => item.TagName.Contains(w))
                    select item.TagId).ToList();

Linq with String Array包含

3 个答案: