从 IRandomAccessStreamReference 读取

Question

我正在使用 windows 10 Windows.ApplicationModel.Chat API。我似乎无法弄清楚如何从 ChatMessageAttachment 对象中的 DataStreamReference 属性读取数据。到目前为止，这是我的代码。

如您所见，它抛出异常并显示消息 "Specified cast is not valid." IBuffer 接口没有任何意义，因为只有 Length 和容量属性.

如果有人能给我一些关于如何阅读 DataStreamReference 属性.

的提示，我将不胜感激

var store = await ChatMessageManager.RequestStoreAsync();
var conversations = await store.GetConversationReader().ReadBatchAsync();

foreach (var conversation in conversations)
{
    var messages = (await conversation.GetMessageReader().ReadBatchAsync(int.MaxValue)).ToArray();
    foreach (var message in messages)
    {
        try
        {
            var dataStream = await message.Attachments.First().DataStreamReference;
            var stream = await dataStream.OpenReadAsync();

            var buffer = new Ass(); // Implements IBuffer
            var count = (uint)stream.Size;

            // Throws exception - "Specified cast is not valid."
            await stream.ReadAsync(buffer, count, Windows.Storage.Streams.InputStreamOptions.ReadAhead);
        }
        catch (Exception ex)
        {

            throw;
        }
    }
}

Answer 1

试试这个：

    using (var datastream = (await dataStream.OpenReadAsync()).AsStreamForRead())
{
    StreamReader reader = new StreamReader(datastream);
    string result = await reader.ReadToEndAsync();
}

从 IRandomAccessStreamReference 读取

Reading from IRandomAccessStreamReference

c#

windows-phone

windows-10

windows-mobile