Question

我的关联域名模型如下：

Project有很多Task s
Task有很多User s

根据User的状态，我需要更新项目中的字段。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;

这使我可以获得具有非活动用户的项目。

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
}

显然这段代码会让我：

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

我在MySQL上，因此我无法简单地利用MultipleActiveResultSets=True。

我如何能够热切地加载这些关联并在foreach循环中访问它们？

Answer 1

急切加载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();

实体框架：访问关联

1 个答案: