WebClient UploadValuesTaskAsync答案

【问题标题】：WebClient UploadValuesTaskAsyncWebClient UploadValuesTaskAsync
【发布时间】：2016-01-24 15:30:03
【问题描述】：

这是我的 WebClient 类：

class MyWebClient : WebClient
{
    private CookieContainer _cookieContainer = new CookieContainer();
    public MyWebClient(string url, string login, string password)
    {
        var data = new NameValueCollection
            {
                { "username",  login},
                { "password",  password}
            };
       UploadValues(new Uri(url), data);
    }
    protected override WebRequest GetWebRequest(Uri address)
    {
        WebRequest request = base.GetWebRequest(address);
        if (request is HttpWebRequest)
        {
            (request as HttpWebRequest).CookieContainer = _cookieContainer;
        }
        return request;
    }
}

这是示例，我想如何使用它：

private MyWebClient _client;

private void btnLogin_Click(object sender, RoutedEventArgs e)
{
     _client = new MyWebClient("http://website/login.php", "account", "pw");
}

private async void btnContent_Click(object sender, RoutedEventArgs e)
{
     _client = await _client.DownloadStringTaskAsync("http://website");
}

我的问题是.. 使用这个 MyWebClient 类，我如何异步登录？希望有人能帮帮我，谢谢！

【问题讨论】：

你不能使用UploadValuesAsync并将其移到构造函数之外吗？

标签： c# wpf async-await webclient

【解决方案1】：

您可以将登录逻辑移到构造函数之外，并像这样使用UploadValuesTaskAsync 方法：

class MyWebClient : WebClient
{
    //...
    private readonly string m_Uri;
    private readonly string m_Login;
    private readonly string m_Password;

    public MyWebClient(string url, string login, string password)
    {
        m_Password = password;
        m_Login = login;
        m_Uri = url;
    }

    public async Task LogIn()
    {
        var data = new NameValueCollection
        {
            {"username", m_Login},
            {"password", m_Password}
        };
        await UploadValuesTaskAsync(new Uri(m_Uri), data);
    }

    //...
}

然后像这样使用它：

private async void btnLogin_Click(object sender, RoutedEventArgs e)
{
     _client = new MyWebClient("http://website/login.php", "account", "pw");
     await _client.LogIn();
}

【讨论】：