Question

我正在编写简单的类，它将连接到SQL DB并从中获取数据。

我想让它异步，但我在异步编程方面遇到了一些问题。

代码：

public async Task<ICommand> ExecuteAsync(SqlConnection connection)
{
    var cmd = new SqlCommand(Query);
    cmd.CommandType = CommandType.Text;
    cmd.Connection = connection;

    if(connection.State != ConnectionState.Open)
        await connection.OpenAsync();

    using (SqlDataReader sqlDataReader = await cmd.ExecuteReaderAsync())
    {
        if (sqlDataReader.HasRows)
        {

            while (await sqlDataReader.ReadAsync())
            {
                Entry = new Entry();
                Entry.ID = (int) sqlDataReader["ID"];
                Entry.User = (string) sqlDataReader["UserName"];
                object o = sqlDataReader["EntryType"];
                Entry.EntryType = o.Equals("Enter") ? EntryType.Enter : EntryType.Leave;
                Entry.DateTime = (DateTime) sqlDataReader["EntryDate"];

            }
        }
    }

使用此代码，调试器始终在OpenAsync（）方法后停止执行。它没有达到下一个声明。

你能告诉我我做错了什么吗？

此致

- 编辑 - 我现在在桌面上运行它（简单单元测试）我添加了try-catch来处理异常。

我的最小样本：

ExecuteAsync方法：

public async Task<ICommand> ExecuteAsync(SqlConnection connection)
{
    var cmd = new SqlCommand(Query);
    cmd.CommandType = CommandType.Text;
    cmd.Connection = connection;

    if(connection.State != ConnectionState.Open)
        await connection.OpenAsync().ConfigureAwait(false);

    using (SqlDataReader sqlDataReader = await cmd.ExecuteReaderAsync().ConfigureAwait(false))
    {
        if (sqlDataReader.HasRows)
        {

            while (await sqlDataReader.ReadAsync().ConfigureAwait(false))
            {
                Entry = new Entry();
                Entry.ID = (int) sqlDataReader["ID"];

// Entry.User =（string）sqlDataReader [＆＃34; UserName＆＃34;]; // object o = sqlDataReader [＆＃34; EntryType＆＃34;]; // Entry.EntryType = o.Equals（＆＃34;输入＆＃34;）？ EntryType.Enter：EntryType.Leave; // Entry.DateTime =（DateTime）sqlDataReader [＆＃34; EntryDate＆＃34;]; } } } 归还这个; }

调用此方法：

    public void ExecuteCommandAsync(ICommand command, ReadFinished continueWith)
    {
        if(continueWith == null)
            throw new NullReferenceException("Parameter 'continueWith' cannot be null");
        command.ExecuteAsync(_connection).ContinueWith(task => continueWith(task.Result)).ConfigureAwait(false);
    }

我的测试用例：

    public void TestMethod1()
    {
        TimeTableDBConnector.DbConnector connector = new DbConnector(null);
        var getEntryByIDCommand = new GetEntryByIDCommand(1);
        ICommand result;
        try
        {
            connector.ExecuteCommandAsync(getEntryByIDCommand, ContinueWith );
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }


    }

    private void ContinueWith(ICommand command)
    {
        GetEntryCommand cmd = (GetEntryCommand) command;
    }

Answer 1

大多数测试框架都支持异步测试，因此如果您更改ExecuteCommandAsync方法以返回Task，您应该能够将测试标记为async和await ExecuteCommandAsync。试一试：

async void TestMethod1()
{
    TimeTableDBConnector.DbConnector connector = new DbConnector(null);
    var getEntryByIDCommand = new GetEntryByIDCommand(1);
    ICommand result;
    try
    {
        await connector.ExecuteCommandAsync(getEntryByIDCommand, ContinueWith );
    }
    catch (Exception e)
    {
        Console.WriteLine(e);
    }
}

SqlDataReader OpenAsync挂起应用程序

1 个答案: