相关疑难解决方法(0)

我知道.Contains()方法确实喜欢LIKE %therm%,.StartsWith()方法确实喜欢LIKE therm%和.EndsWith()方法一样LIKE %therm但是......

有没有办法在下面做**Linq to Entities**？

SELECT * FROM [dbo].[Users] WHERE Name LIKE 'rodrigo%otavio%diniz%waltenberg'

PS:我正在使用LINQ to ENTITIES.不是LINQ TO SQL

在linq to Entities中,我们需要一个类似"sql like"的方法.我们已经为IQueryable实现了我们自己的扩展方法,因为包含的方法对我们不起作用,因为它不接受像'%a%b%'这样的模式

创建的代码是:

private const char WildcardCharacter = '%';

public static IQueryable<TSource> WhereLike<TSource>(this IQueryable<TSource> _source, Expression<Func<TSource, string>> _valueSelector, string _textSearch)
{
    if (_valueSelector == null)
    {
        throw new ArgumentNullException("valueSelector");
    }

        return _source.Where(BuildLikeExpressionWithWildcards(_valueSelector, _textSearch));
}

private static Expression<Func<TSource, bool>> BuildLikeExpressionWithWildcards<TSource>(Expression<Func<TSource, string>> _valueSelector, string _textToSearch)
{
    var method = GetPatIndexMethod();

    var body = Expression.Call(method, Expression.Constant(WildcardCharacter + _textToSearch + WildcardCharacter), _valueSelector.Body);

    var parameter = _valueSelector.Parameters.Single();
    UnaryExpression expressionConvert = Expression.Convert(Expression.Constant(0), typeof(int?));
    return Expression.Lambda<Func<TSource, bool>> (Expression.GreaterThan(body, expressionConvert), parameter);
}

private static MethodInfo GetPatIndexMethod() …

如何使用edo实体框架在ASP.net MVC中获取通配符文本搜索(如SQL的"like"语句)？

我以为这会起作用:

var elig = (from e in _documentDataModel.Protocol_Eligibility_View
            where e.criteria.Contains(query)
            select e);

但即使搜索肯定在数据库中的查询字符串,它也不会返回任何结果.我究竟做错了什么？