Entity Framework Core 中的 PredicateBuilder 与 And & Or (in) 子句 n 相同的查询

问题描述

我正在尝试在 Entity Framework Core 的同一查询中使用 & 和 with

// http://www.albahari.com/nutshell/predicatebuilder.aspx
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);
    }

}

我正在尝试类似的场景

select * 
from transaction
where channel = 1
  and msisdn = '123123123'
  and service in (1,2,3)

或

select * 
from transaction
where channel = 1
  and msisdn = '123123123'
  and (service = 1 or service = 2 or service = 3)
    
    
private static Expression<Func<Transaction,bool>> CreateSearchPredicate(TransactionSearchQuery search,User user)
{
    var predicate = PredicateBuilder.True<Transaction>();           
           
    if (search.fk_channel_id > 0)
    {
        predicate = predicate.And(p => p.fk_channel_id == search.fk_channel_id);
    }

    // msisdn
    if (!string.IsNullOrWhiteSpace(search.msisdn))
    {
        predicate = predicate.And(p => p.msisdn == search.msisdn);
    } 

    if (search.transactionStates != null && search.transactionStates.Count > 0)
    {
        var predicateX = PredicateBuilder.True<Transaction>();//also tried with False

        foreach (var val in search.transactionStates)
        {
            predicateX = predicateX.Or(p => p.statusid == val);
        }

        predicate = predicate.And(predicateX);
    }          

    return predicate;
}

请帮帮我 - 我需要在 CreateSearchPredicate 中进行哪些更改才能运行 And & In（或同时运行线索）

我的数据库是 MysqL 我在存储库中的代码就像

 public override IEnumerable<Transaction> GetAll(Expression<Func<Transaction,bool>> predicate)
        {
            return _context.Set<Transaction>().Include(h => h.ServiceOwner).Include(h => h.TransactionState).Include(h => h.OriginationValidationState).Include(h => h.CommunicationChannel).ThenInclude(h => h.Channel).Where(predicate).AsEnumerable();
            //return _context.Set<Transaction>().Where(predicate).AsEnumerable();
        }

解决方法

不知道我的解决方案是否正确，但我使用包含列表的子句来解决它，并且谓词如下

            if (search.transactionStates != null && search.transactionStates.Count > 0)
            {
                predicate = predicate.And(p => search.transactionStates.Contains(p.statusid));
            }

            if (search.services != null && search.services.Count > 0)
            {

                predicate = predicate.And(p => p.fk_authentication_service_id.HasValue && search.services.Contains(p.fk_authentication_service_id.Value));
            }

            if (search.channels != null && search.channels.Count > 0)
            {
                predicate = predicate.And(p => p.fk_channel_id.HasValue && search.channels.Contains(p.fk_channel_id.Value));
            }

entity-framework-core mysql predicatebuilder