内部的.NET Framework数据提供程序错误1025 [英] Internal .NET Framework Data Provider error 1025

问题描述

IQueryable<Organization> query = context.Organizations;

Func<Reservation, bool> predicate = r => !r.IsDeleted;

query.Select(o => new { 
    Reservations = o.Reservations.Where(predicate)
}).ToList();

这个查询会引发内部的.NET Framework数据提供程序错误1025的例外，但低于查询不。

this query throws Internal ".NET Framework Data Provider error 1025" exception but below query does not.

query.Select(o => new { 
    Reservations = o.Reservations.Where( r => !r.IsDeleted)
}).ToList();

我需要使用第一个，因为我需要检查一些if语句构建正确的predicate。我知道，我不能在这个circumtence这就是为什么我通过委托作为参数来使用if语句。

I need to use first one because i need to check few if statement for construct right predicate. I know that i can not use if statements in this circumtence that is why i pass delegate as parameter.

我怎样才能使它发挥作用的第一个查询？

How can i make it work first query ?

推荐答案

虽然上述回答是真实的，请注意，当尝试一个select语句一个人打电话后使用它 AsQueryable已（）明确，否则编译器会认为我们尝试使用IEnumerable的方法，它期待 Func键，而不是防爆pression＆LT; Func键与GT;

While the above answers are true, note that when trying to use it after a select statement one has to call AsQueryable() explicitly, otherwise the compiler will assume that we are trying to use IEnumerable methods, which expect a Func and not Expression<Func>.

这可能是楼主的问题，否则编译器会抱怨的大部分时间，它正在寻找防爆pression＆LT; Func键＆GT; 和没有 Func键。

This was probably the issue of the original poster, as otherwise the compiler will complain most of the time that it is looking for Expression<Func> and not Func.

演示： 下面将失败：

MyContext.MySet.Where(m => m.SubCollection.Select(s => s.SubItem).Any(expr)).Load()

在下面的工作：

While the following will work:

MyContext.MySet.Where(m => 
      m.SubCollection.Select(s => s.SubItem).AsQueryable().Any(expr))
         .Load()

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