实体框架：访问协会

Question

我的域模型关联如下：

• Project有许多Task小号
• Task有许多User小号

取决于User的状态，我需要更新项目中的一个字段。我的查询如下：

var projects = from project in _data.projects 
       join task in _data.tasks on project.ProjectID equals task.ProjectID 
       join user in _data.usersactive on task.TaskID equals user.TaskID 
       where user.Active == false 
       select project; 

这使我可以得到有用户不活动的项目。

foreach (Project project in projects) 
{ 
    bool needUpdate = false; 

    foreach (Task task in project.tasks) 
    { 
     foreach (User user in task.users) 
     { 
      // Depending on state of user 
      // needUpdate = true; 
     } 
    } 

    // If needUpdate = true 
    // Do something 
} 

显然这段代码是要找个：

There is already an open DataReader associated with this Connection which must be closed first.

我在MySQL然而，正因为如此我不能够简单地利用MultipleActiveResultSets=True。

我将如何能够急切地加载这些关联，并让他们可以在foreach循环中访问？

Answer 1

热切加载LINQ集：

var projects = (from project in _data.projects 
       join task in 
         _data.tasks on project.ProjectID equals task.ProjectID 
       join user in 
         _data.usersactive on task.TaskID equals user.TaskID 
       where user.Active == false 
       select project).ToList();