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LinqKit谓词或with Contains的计算结果等于

linqkit entity-framework c#

mr.coffee · 技术社区 · 7 年前

我正在实现对我的应用程序的搜索。除非用户的搜索是通过搜索相关实体级联的,否则搜索是有效的。我已经调试了代码并测试了实体框架生成的SQL。我发现问题是 Contains() 当它应该是“LIKE”时,在SQL中转换为“=”。 包含() 在FirstName、MiddleName等的初始谓词中起作用,但在 if (cascade) 代码块。

public IList<Individual> Find(string search, bool cascade, bool includeInactive)
{
    _context.Database.Log = s => System.Diagnostics.Debug.WriteLine(s);
    IQueryable<Individual> query = _context.Individuals;
    if (!string.IsNullOrWhiteSpace(search))
    {
        search = search.Trim();
        string[] searchParts = search.Split(' ');
        ExpressionStarter<Individual> predicate = PredicateBuilder.New<Individual>(false);
        foreach (string searchPart in searchParts)
        {
            predicate = predicate.Or(c =>
                c.FirstName.Contains(searchPart) || c.MiddleNames.Contains(searchPart) ||
                c.LastName.Contains(searchPart) || c.PreferredName.Contains(searchPart));
            if (cascade)
            {
                predicate = predicate.Or(c =>
                    c.IndividualOrganisationGroups.Select(og => og.OrganisationGroup).Select(g => g.Group.Name)
                        .Contains(searchPart));
            }
        }
        query = query.Where(predicate);
    }
    if (!includeInactive)
    {
        query = query.Where(c => c.Active);
    }
    return query.ToList();
}

从EF生成的SQL:

SELECT 
    [Extent1].[ID] AS [ID], 
    [Extent1].[RegistrationTypeID] AS [RegistrationTypeID], 
    [Extent1].[Title] AS [Title], 
    [Extent1].[FirstName] AS [FirstName], 
    [Extent1].[MiddleNames] AS [MiddleNames], 
    [Extent1].[LastName] AS [LastName], 
    [Extent1].[PreferredName] AS [PreferredName], 
    [Extent1].[RegistrationNumber] AS [RegistrationNumber], 
    [Extent1].[Username] AS [Username], 
    [Extent1].[AzureID] AS [AzureID], 
    [Extent1].[Notes] AS [Notes], 
    [Extent1].[Active] AS [Active], 
    [Extent1].[CreatedDate] AS [CreatedDate], 
    [Extent1].[CreatedBy] AS [CreatedBy], 
    [Extent1].[UpdatedDate] AS [UpdatedDate], 
    [Extent1].[UpdatedBy] AS [UpdatedBy]
    FROM [dbo].[Individual] AS [Extent1]
    WHERE ([Extent1].[FirstName] LIKE @p__linq__0 ESCAPE '~') OR ([Extent1].[MiddleNames] LIKE @p__linq__1 ESCAPE '~') OR ([Extent1].[LastName] LIKE @p__linq__2 ESCAPE '~') OR ([Extent1].[PreferredName] LIKE @p__linq__3 ESCAPE '~') OR ( EXISTS (SELECT 
        1 AS [C1]
        FROM   [dbo].[IndividualOrganisationGroup] AS [Extent2]
        INNER JOIN [dbo].[OrganisationGroup] AS [Extent3] ON [Extent2].[OrganisationGroupID] = [Extent3].[ID]
        INNER JOIN [dbo].[Group] AS [Extent4] ON [Extent3].[GroupID] = [Extent4].[ID]
        WHERE ([Extent1].[ID] = [Extent2].[IndividualID]) AND (([Extent4].[Name] = @p__linq__4) OR (1 = 0))
    ))
-- p__linq__0: '%screen%' (Type = AnsiString, Size = 8000)

-- p__linq__1: '%screen%' (Type = AnsiString, Size = 8000)

-- p__linq__2: '%screen%' (Type = AnsiString, Size = 8000)

-- p__linq__3: '%screen%' (Type = AnsiString, Size = 8000)

-- p__linq__4: 'screen' (Type = AnsiString, Size = 8000)

有问题的SQL(最后一个WHERE子句):

WHERE ([Extent1].[ID] = [Extent2].[IndividualID]) AND (([Extent4].[Name] = @p__linq__4) OR (1 = 0))

它应该是什么样子:

WHERE ([Extent1].[ID] = [Extent2].[IndividualID]) AND (([Extent4].[Name] LIKE @p__linq__4) OR (1 = 0))

所以我的问题是,如何将这些代码翻译成实体框架SQL中的LIKE?

predicate = predicate.Or(c =>
                    c.IndividualOrganisationGroups.Select(og => og.OrganisationGroup).Select(g => g.Group.Name)
                        .Contains(searchPart));

1 回复 | 直到 7 年前

Ivan Stoev 7 年前

它与LINQKit谓词生成器无关。原因是

c.IndividualOrganisationGroups.Select(og => og.OrganisationGroup).Select(g => g.Group.Name)

是 IEnumerable<string> IQueryable<string> ),所以你的目标是 Enumerable Queryable ) Contains 方法而不是 string.Contains 就像其他地方一样。

而不是 Select 包含 ,你真正需要的是 Any 扩展方法。

示例中最简洁的语法是:

c => c.IndividualOrganisationGroups
    .Any(og => og.OrganisationGroup.Group.Name.Contains(searchPart))

当然,如果您需要检查 Group (甚至没有),然后使用 + Any :

c => c.IndividualOrganisationGroups
    .Select(og => og.OrganisationGroup.Group)
    .Any(g => g.Name.Contains(searchPart))

或者最自然的方法,通过以“正常”的方式编写查询,将带有过滤器的集合转换为单bool。例如 , Where 等,并将参数化 任何

c => c.IndividualOrganisationGroups
    .Select(og => og.OrganisationGroup.Group)
    .Where(g => g.Name.Contains(searchPart))
    .Any())