convert 方法等待查询完成

Question

我正在使用下面的查询从数据库中加载一些数据。我可以使用此方法等待直到此查询使用 await-async 完成吗？

public static void LoadData()
        {
            using (MyEntities entities = new MyEntities())
            {
                List<Employee> Employees = (from d in entities.Employees
                                            where d.Id > 100
                                            select new Employee
                                            {
                                                Name = d.LastName + ", " + d.FirstName
                                                DoB = d.dob
                                            }).ToList();
            }
}

Answer 1

Entity Framework 从 EF 6.0 开始有一个 ToListAsync 方法，即 returns 一个 Task<List<T>>，允许您 await 它。

Answer 2

是的，你可以使用这个方法http://msdn.microsoft.com/en-us/library/dn220262(v=vs.113).aspx；

public static async void LoadData()
    {
        using (MyEntities entities = new MyEntities())
        {
            List<Employee> Employees = await (from d in entities.Employees
                                        where d.Id > 100
                                        select new Employee
                                        {
                                            Name = d.LastName + ", " + d.FirstName
                                            DoB = d.dob
                                        }).AsQueryable().ToListAsync();
        }
}

如果 MyEntities 是 DbContext，您可以使用

List<Employee> Employees = 
                   await entities.Set<Employee>()
                       .Where(d => d.Id > 100)
                       .Select(
                        d =>
                        new Employee
                        {
                            Name = d.LastName + ", " + d.FirstName,
                            DoB = d.dob
                        }).ToListAsync();

convert 方法等待查询完成

convert method to wait until query finishes

c#

.net-4.0

task

async-await

entity-framework-6.1