如何从机器人框架 C# 中读取附件内容？答案

【问题标题】：How to read attachment content from bot framework C#?如何从机器人框架 C# 中读取附件内容？
【发布时间】：2018-01-04 09:46:00
【问题描述】：

我正在编写一个机器人，并希望用户向我发送一个附件，我想阅读该附件并将其翻译成对象。

到目前为止，我有以下代码：

if (message.Attachments != null && message.Attachments.Any())
{
    var attachment = message.Attachments.First();
    using (HttpClient httpClient = new HttpClient())
    {
        if ((message.ChannelId.Equals("skype", StringComparison.InvariantCultureIgnoreCase) || message.ChannelId.Equals("msteams", StringComparison.InvariantCultureIgnoreCase)) && new Uri(attachment.ContentUrl).Host.EndsWith("skype.com"))
        {
            var token = await new MicrosoftAppCredentials().GetTokenAsync();
            httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
        }

        var responseMessage = await httpClient.GetAsync(attachment.ContentUrl); 
        var contentLenghtBytes = responseMessage.Content.Headers.ContentLength; // this is populated correctly

        if(attachment.Name.ToLower().Equals("opportunity.xlsx"))
        {
            var temp = attachment.Content; // This Content is always null, even though everything else is populated.
        }
    }
}

谁能建议我如何阅读附件 xlsx 内容？

谢谢

【问题讨论】：

标签： c# excel bots attachment botframework

【解决方案1】：

附件在Content 属性中不可用。您首先需要使用ContentUrl 下载附件，然后在下载文件后使用响应消息执行您想要的任何操作。

查看Receive-Attachments C# 示例。

public virtual async Task MessageReceivedAsync(IDialogContext context, IAwaitable<IMessageActivity> argument)
{
    var message = await argument;

    if (message.Attachments != null && message.Attachments.Any())
    {
        var attachment = message.Attachments.First();
        using (HttpClient httpClient = new HttpClient())
        {
            // Skype & MS Teams attachment URLs are secured by a JwtToken, so we need to pass the token from our bot.
            if ((message.ChannelId.Equals("skype", StringComparison.InvariantCultureIgnoreCase) || message.ChannelId.Equals("msteams", StringComparison.InvariantCultureIgnoreCase)) 
                && new Uri(attachment.ContentUrl).Host.EndsWith("skype.com"))
            {
                var token = await new MicrosoftAppCredentials().GetTokenAsync();
                httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
            }

            var responseMessage = await httpClient.GetAsync(attachment.ContentUrl);

            var contentLenghtBytes = responseMessage.Content.Headers.ContentLength;

            await context.PostAsync($"Attachment of {attachment.ContentType} type and size of {contentLenghtBytes} bytes received.");
        }
    }
    else
    {
        await context.PostAsync("Hi there! I'm a bot created to show you how I can receive message attachments, but no attachment was sent to me. Please, try again sending a new message including an attachment.");
    }

    context.Wait(this.MessageReceivedAsync);
}

【讨论】：

抱歉，这与我上面的代码 sn-p 有何不同？
你正在做的附件。内容是错误的。由于您正在下载附件，因此您应该使用 responseMessage.Content 来访问该文件

【解决方案2】：

如果这就是您的意思，您将不得不使用其他一些 dll 来读取 excel 数据。你的意思是在上传后读取excel文件的内容然后你可以使用https://github.com/ExcelDataReader/ExcelDataReader

【讨论】：