C# 辛塔克斯 基本上考虑事物应该是“一直向下”的范例。这意味着，在任何给定异步调用堆栈的顶层，都应该有一些东西来管理任务。对于WinForms、WPF、ASP.NET等技术，有内置的机制来实现这一点。对于一个控制台应用程序，你基本上是赤裸裸的。main（）方法是最顶层的，需要在堆栈上管理它下面的任务。

您可能想做的是

static void Main(string[] args)
{
    var enquiry = new InquireDatabaseAsync().DoWork();
    while (!enquiry.IsCompleted)
    {
        Console.WriteLine("Doing Stuff on the Main Thread...");
    }

    // In case there were any exceptions.
    enquiry.Wait();
}      

---

你可能想做的是

static void Main(string[] args)
{
    var enquiry = new InquireDatabaseAsync().DoWork();
    while (!enquiry.IsCompleted)
    {
        Console.WriteLine("Doing Stuff on the Main Thread...");
    }

    // In case there were any exceptions.
    enquiry.Wait();
}      

---

你可能想做的是

static void Main(string[] args)
{
    var enquiry = new InquireDatabaseAsync().DoWork();
    while (!enquiry.IsCompleted)
    {
        Console.WriteLine("Doing Stuff on the Main Thread...");
    }

    // In case there were any exceptions.
    enquiry.Wait();
}      

---

你可能想做的是

static void Main(string[] args)
{
    var enquiry = new InquireDatabaseAsync().DoWork();
    while (!enquiry.IsCompleted)
    {
        Console.WriteLine("Doing Stuff on the Main Thread...");
    }

    // In case there were any exceptions.
    enquiry.Wait();
}      

---

虽然

DoWork

在内部等待任务，但它会立即返回给调用者！因此，如果调用方希望在继续之前等待任务终止，则必须再次等待

inq.DoWork().Wait();

---

虽然

DoWork

在内部等待任务，但它会立即返回给调用者！因此，如果调用方希望在继续之前等待任务终止，则必须再次等待

inq.DoWork().Wait();

---

虽然

DoWork

在内部等待任务，但它会立即返回给调用者！因此，如果调用方希望在继续之前等待任务终止，则必须再次等待

inq.DoWork().Wait();

---

虽然

DoWork

在内部等待任务，但它会立即返回给调用者！因此，如果调用方希望在继续之前等待任务终止，则必须再次等待

inq.DoWork().Wait();

---

这段代码有几个问题。考虑使用如下的东西：

using System;
using System.Threading.Tasks;

namespace ConsoleApplication6
{
    class DatabaseAccessor
    {
        static async void Main(string[] args)
        {
            await Task.Run(() =>
            {
                InquireDatabaseAsync.LongRunningOperation();
            });
        }
    }

    public static class InquireDatabaseAsync
    {
        public static void LongRunningOperation()
        {
            Data_connection2 dbobject = new Data_connection2();
            SQLiteConnection m_dbConnection = new SQLiteConnection();
            m_dbConnection.ConnectionString = dbobject.datalocation2();
            m_dbConnection.Open();

            string sql = "SELECT * FROM Commands WHERE Id = (SELECT MAX(Id) FROM Commands)";
            SQLiteCommand SQLcommand = new SQLiteCommand(sql, m_dbConnection);

            while (true)
            {
                System.Threading.Thread.Sleep(1000);
                var reader = sqlCommand.ExecuteReader();
                while (reader.Read())
                    Console.WriteLine("Id: " + reader["Id"] + "\tInstruction: " + reader["Instruction"] + "\tCellular: " + reader["Cellular"] + "\tTimestamp: " + reader["Timestamp"]);
                break;
            }
            Console.WriteLine("Finished.");
        }
    }

    class Data_connection2
    {
        public string datalocation2()
        {
            String dir = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
            return "Data Source=" + dir + "\\database9.sqlite";
        }
    }
}

---

这段代码有几个问题。考虑使用如下的东西：

using System;
using System.Threading.Tasks;

namespace ConsoleApplication6
{
    class DatabaseAccessor
    {
        static async void Main(string[] args)
        {
            await Task.Run(() =>
            {
                InquireDatabaseAsync.LongRunningOperation();
            });
        }
    }

    public static class InquireDatabaseAsync
    {
        public static void LongRunningOperation()
        {
            Data_connection2 dbobject = new Data_connection2();
            SQLiteConnection m_dbConnection = new SQLiteConnection();
            m_dbConnection.ConnectionString = dbobject.datalocation2();
            m_dbConnection.Open();

            string sql = "SELECT * FROM Commands WHERE Id = (SELECT MAX(Id) FROM Commands)";
            SQLiteCommand SQLcommand = new SQLiteCommand(sql, m_dbConnection);

            while (true)
            {
                System.Threading.Thread.Sleep(1000);
                var reader = sqlCommand.ExecuteReader();
                while (reader.Read())
                    Console.WriteLine("Id: " + reader["Id"] + "\tInstruction: " + reader["Instruction"] + "\tCellular: " + reader["Cellular"] + "\tTimestamp: " + reader["Timestamp"]);
                break;
            }
            Console.WriteLine("Finished.");
        }
    }

    class Data_connection2
    {
        public string datalocation2()
        {
            String dir = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
            return "Data Source=" + dir + "\\database9.sqlite";
        }
    }
}

---

这段代码有几个问题。考虑使用如下的东西：

using System;
using System.Threading.Tasks;

namespace ConsoleApplication6
{
    class DatabaseAccessor
    {
        static async void Main(string[] args)
        {
            await Task.Run(() =>
            {
                InquireDatabaseAsync.LongRunningOperation();
            });
        }
    }

    public static class InquireDatabaseAsync
    {
        public static void LongRunningOperation()
        {
            Data_connection2 dbobject = new Data_connection2();
            SQLiteConnection m_dbConnection = new SQLiteConnection();
            m_dbConnection.ConnectionString = dbobject.datalocation2();
            m_dbConnection.Open();

            string sql = "SELECT * FROM Commands WHERE Id = (SELECT MAX(Id) FROM Commands)";
            SQLiteCommand SQLcommand = new SQLiteCommand(sql, m_dbConnection);

            while (true)
            {
                System.Threading.Thread.Sleep(1000);
                var reader = sqlCommand.ExecuteReader();
                while (reader.Read())
                    Console.WriteLine("Id: " + reader["Id"] + "\tInstruction: " + reader["Instruction"] + "\tCellular: " + reader["Cellular"] + "\tTimestamp: " + reader["Timestamp"]);
                break;
            }
            Console.WriteLine("Finished.");
        }
    }

    class Data_connection2
    {
        public string datalocation2()
        {
            String dir = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
            return "Data Source=" + dir + "\\database9.sqlite";
        }
    }
}

---

这段代码有几个问题。考虑使用如下的东西：

using System;
using System.Threading.Tasks;

namespace ConsoleApplication6
{
    class DatabaseAccessor
    {
        static async void Main(string[] args)
        {
            await Task.Run(() =>
            {
                InquireDatabaseAsync.LongRunningOperation();
            });
        }
    }

    public static class InquireDatabaseAsync
    {
        public static void LongRunningOperation()
        {
            Data_connection2 dbobject = new Data_connection2();
            SQLiteConnection m_dbConnection = new SQLiteConnection();
            m_dbConnection.ConnectionString = dbobject.datalocation2();
            m_dbConnection.Open();

            string sql = "SELECT * FROM Commands WHERE Id = (SELECT MAX(Id) FROM Commands)";
            SQLiteCommand SQLcommand = new SQLiteCommand(sql, m_dbConnection);

            while (true)
            {
                System.Threading.Thread.Sleep(1000);
                var reader = sqlCommand.ExecuteReader();
                while (reader.Read())
                    Console.WriteLine("Id: " + reader["Id"] + "\tInstruction: " + reader["Instruction"] + "\tCellular: " + reader["Cellular"] + "\tTimestamp: " + reader["Timestamp"]);
                break;
            }
            Console.WriteLine("Finished.");
        }
    }

    class Data_connection2
    {
        public string datalocation2()
        {
            String dir = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
            return "Data Source=" + dir + "\\database9.sqlite";
        }
    }
}

---

“看来主线程没有等待异步进程。”为什么会这样？您希望哪段代码会让它等待？“看来主线程没有等待异步进程。”为什么会这样？您希望哪段代码会让它等待？“看来主线程没有等待异步进程。”为什么会这样？您希望哪段代码会让它等待？“看来主线程没有等待异步进程。”为什么会这样？你希望哪一段代码能让它等待？一个人不能在一个本身不是

async

的方法中使用

await

。一个人不能在一个本身不是

async

的方法中使用

await

。一个人不能在一个本身不是

async

的方法中使用

await

。一个人不能使用

await

在一个本身不是

async

的方法中。嗨，大卫，谢谢你的老练评论。这实际上解决了我的疑问。嗨，大卫，谢谢你老练的评论。这实际上解决了我的疑问。嗨，大卫，谢谢你老练的评论。这实际上解决了我的疑问。嗨，大卫，谢谢你老练的评论。它实际上解决了我的疑问。对不起，由于SQLite的原因，我无法编译这段代码。我没有意识到不能有一个异步main方法。不管怎么说，这些技术与你想做的事情类似。这是在讨论。抱歉，我无法编译此代码，因为SQLite的东西。我没有意识到不能有一个异步main方法。不管怎么说，这些技术与你想做的事情类似。这是在讨论。抱歉，我无法编译此代码，因为SQLite的东西。我没有意识到不能有一个异步main方法。不管怎么说，这些技术与你想做的事情类似。这是在讨论。抱歉，我无法编译此代码，因为SQLite的东西。我没有意识到不能有一个异步main方法。不管怎么说，这些技术与你想做的事情类似。这一点将在会议上讨论。