我正在使用C#,Entity Framework Code First 4.4.0.0和.NET Framework 4.0开发一个库。

我有以下代码:

string[] keywords = null;
if (query_string != null)
    keywords = query_string.Split(' ');

// Check parameter. It will throw an exception.
ParameterCheck.CheckObjectId(user_id);

// Convert parameter to int.
int userId = Int32.Parse(user_id);

try
{
    using (var context = new AdnLineContext())
    {
        context.Configuration.ProxyCreationEnabled = false;

        //IQueryable<User> query = context.Users;
        IQueryable<User> query = context.Users.AsExpandable();
        var predicate = PredicateBuilder.False<User>();

        foreach (string keyword in keywords)
        {
            string temp = keyword;

            predicate = predicate.Or(u => u.Name.Contains(temp) ||
                                     u.State.Contains(temp) ||
                                     u.HashTags.Contains(temp));
        }
        query.Where(predicate);
        query.Include("WhoHasBlockedMe").Include("Friends");

        var users = query.ToList();

        [ ... ]
    }
}


如果keywords = {"john", "happy"}我想获得此SQL:

select * from users where
users.name like '%john%' or
users.state like '%john%' or
users.hashtags like '%john%' or
users.name like '%happy%' or
users.state like '%happy%' or
users.hashtags like '%happy%';


如何使用PredicateBuilder做到这一点?

顺便说一句,我已经从http://www.albahari.com/nutshell/predicatebuilder.aspx下载了LinqKit

更新
我在var users = query.ToList();处添加了一个断点,并且query具有以下SQL:

{SELECT
[Extent1].[UserId] AS [UserId],
[...]
FROM [dbo].[Users] AS [Extent1]}


它没有Where子句。

最佳答案

您的问题在这里:

query.Where(predicate);
query.Include("WhoHasBlockedMe").Include("Friends");

var users = query.ToList();


.Where.Include不会修改基础查询,它们会返回一个新查询。

使用

query = query.Where(predicate);
query = query.Include("WhoHasBlockedMe").Include("Friends");

var users = query.ToList();


代替。

07-28 08:12