EF Core Second level ThenInclude misworks

本文介绍了EF Core Second level ThenInclude misworks的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

假设首先拥有这些模型:

Assume having these models first:

Method 有一个 OriginalCodeOriginalCode 有很多 MutantMutant 有很多 ParseSubTrees

Method that has one OriginalCode OriginalCode that has many Mutants Mutant that has many ParseSubTrees

现在在查询 Method 时，我希望加载另一个.所以我有以下几点:

Now when querying on Method I want the other being loaded. So I have the following:

Method targetMethod = dBContext.Methods .Include(me => me.OriginalCode) .ThenInclude(oc => oc.Mutants) .FirstOrDefault(me => me.Id == id);

下一步是额外包含ParseSubTree.但问题是我无法访问它.见下图:

and the next step is to include additionally the ParseSubTree. But the thing is that I can't access it. See the following Image:

问题是mu 是一个列表，而不是一个对象引用"！

the problem is "mu is a list instead of being an object reference"!

我的错在哪里！

TG.

推荐答案

这是集合类型导航属性的 ThenInclude 重载的一个已知 Intellisense 问题，由 在容错案例 #8237 中补全 lambda 参数的缺失成员 Roslyn GitHub 问题.

This is a known Intellisense issue with the ThenInclude overload for collection type navigation properties, tracked by the Completion missing members of lambda parameter in fault tolerance case #8237 Roslyn GitHub issue.

在修复之前，只需键入属性的名称，它就会成功编译并按预期工作.

Until it gets fixed, simply type the name of the property and it will compile successfully and work as expected.

.ThenInclude(mu => mu.ParseSubTrees)

更新:现在它甚至在 包括多级EF Core 文档的 部分:

Update: Now it's even specifically mentioned in the Including multiple levels section of the EF Core documentation:

注意

当前版本的 Visual Studio 提供不正确的代码完成选项，并且在集合导航属性之后使用 ThenInclude 方法时，可能会导致正确的表达式被标记为语法错误.这是在 github/dotnet/roslyn/issues 跟踪的 IntelliSense 错误的症状/8237.只要代码正确并且可以成功编译，就可以安全地忽略这些虚假的语法错误.

Current versions of Visual Studio offer incorrect code completion options and can cause correct expressions to be flagged with syntax errors when using the ThenInclude method after a collection navigation property. This is a symptom of an IntelliSense bug tracked at github/dotnet/roslyn/issues/8237. It is safe to ignore these spurious syntax errors as long as the code is correct and can be compiled successfully.