我有一个List< string>变量计数,我想查询(通过LINQ)一个表来查找包含Text列中任何字符串的任何项目.
试过这个(不起作用)：
items = from dbt in database.Items
where (stringList.FindAll(s => dbt.Text.Contains(s)).Count > 0)
select dbt;
查询将类似于：
select * from items where text like '%string1%' or text like '%string2%'
这可能吗？
解决方法
查看这篇文章,做你想做的事：
http://www.albahari.com/nutshell/predicatebuilder.aspx
这就像一场梦.我基本上剪切并粘贴了他们的代码并将其取回(当然是我自己的数据方案)：
http://www.albahari.com/nutshell/predicatebuilder.aspx
这就像一场梦.我基本上剪切并粘贴了他们的代码并将其取回(当然是我自己的数据方案)：
SELECT [t0].[Id],[t0].[DateCreated],[t0].[Name] ... FROM [dbo].[Companies] AS [t0] WHERE ([t0].[Name] LIKE @p0) OR ([t0].[Name] LIKE @p1)
这是我为概念证明运行的代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Linq.Expressions;
namespace PredicateTest
{
class Program
{
static void Main(string[] args)
{
DataClasses1DataContext dataContext = new DataClasses1DataContext();
Program p = new Program();
Program.SearchCompanies("test","test2");
var pr = from pi in dataContext.Companies.Where(Program.SearchCompanies("test","test2")) select pi;
}
DataClasses1DataContext dataContext = new DataClasses1DataContext();
public static Expression<Func<Company,bool>> SearchCompanies(
params string[] keywords)
{
var predicate = PredicateBuilder.False<Company>();
foreach (string keyword in keywords)
{
string temp = keyword;
predicate = predicate.Or(p => p.Name.Contains(temp));
}
return predicate;
}
}
public static class PredicateBuilder
{
public static Expression<Func<T,bool>> True<T>() { return f => true; }
public static Expression<Func<T,bool>> False<T>() { return f => false; }
public static Expression<Func<T,bool>> Or<T>(this Expression<Func<T,bool>> expr1,Expression<Func<T,bool>> expr2)
{
var invokedExpr = Expression.Invoke(expr2,expr1.Parameters.Cast<Expression>());
return Expression.Lambda<Func<T,bool>>
(Expression.OrElse(expr1.Body,invokedExpr),expr1.Parameters);
}
public static Expression<Func<T,bool>> And<T>(this Expression<Func<T,bool>>
(Expression.AndAlso(expr1.Body,expr1.Parameters);
}
}
}
我建议去网站寻找代码和解释.
(我要留下第一个答案,因为如果你需要一个IN声明它会很好用)
