private async Task GetValueAsync()
{
    try
    {
        using (WebClient client = new WebClient())
        {
            //地址
            string path = $"{webUrl}/api/Value";
            client.Headers.Add(HttpRequestHeader.Authorization, $"Bearer {token}");
            string value = await client.DownloadStringTaskAsync(path);
            txbMsg.Text = $"获取到数据={value}";
        }
    }
    catch (Exception ex)
    {
        txbMsg.Text = $"获取数据出错={ex.Message}";
    }
}