Question

我正在使用LINQ和EntityFramewwork 6，并且我需要将大部分方法转换为异步任务。

但是，我无法弄清楚为什么在这两个特定场景中我得到这些设计时编译消息。如果有人可以向我解释我需要做什么来使任务变得异步，那将非常感激。

我要转换的第一种同步任务如下：

public List<Category> GetProjectsByCategoryID(Int16 categoryid)
        {
            try
            {
                using (YeagerTechEntities DbContext = new YeagerTechEntities())
                {
                    DbContext.Configuration.ProxyCreationEnabled = false;
                    DbContext.Database.Connection.Open();

                    var category = DbContext.Categories.Include("Projects").Where(p => p.CategoryID == categoryid).ToList();

                    return category;
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

当我尝试将上述方法更改为异步任务时（见下文），我不知道放置inbetween the "Include("Projects").(p"

的异步方法

public async Task<List<Category>> GetProjectsByCategoryID(Int16 categoryid)
        {
            try
            {
                using (YeagerTechEntities DbContext = new YeagerTechEntities())
                {
                    DbContext.Configuration.ProxyCreationEnabled = false;
                    DbContext.Database.Connection.Open();

                    var category = await DbContext.Categories.Include("Projects").(p => p.CategoryID == categoryid);

                    return category;
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

如何将此同步方法转换为异步方法？

public List<CustomerEmail> GetCustomerDropDownList()
        {
            try
            {
                using (YeagerTechEntities DbContext = new YeagerTechEntities())
                {
                    DbContext.Configuration.ProxyCreationEnabled = false;
                    DbContext.Database.Connection.Open();

                    var customers = DbContext.Customers.Select(s =>
                        new CustomerEmail()
                        {
                            CustomerID = s.CustomerID,
                            Email = s.Email
                        }).ToList();

                    return customers;
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

Answer 1

你非常亲密：

public async Task<List<CustomerEmail>> GetCustomerDropDownList()
{
    try
    {
        using (YeagerTechEntities DbContext = new YeagerTechEntities())
        {
            DbContext.Configuration.ProxyCreationEnabled = false;
            DbContext.Database.Connection.Open();

            var customers = await DbContext.Customers.Select(s =>
            new CustomerEmail()
            {
                CustomerID = s.CustomerID,
                Email = s.Email
            }).ToListAsync();

            return customers;
        }
    }
    catch (Exception ex)
    {
        throw ex;
    }
}

注意ToListAsync（）。这将显式加载和解析您的查询，但将以异步方式执行此操作。

尝试将同步任务转换为异步任务

1 个答案: