c# - 如何在C#中实现IRandomAccessStream？

我想在C#中实现IRandomAccessStream的实例(它将返回实时生成的数据)。流实际上不需要是可写或可搜索的，但是我想在ReadAsync方法(实际上是IInputStream的一部分)中返回自己的数据。

public IAsyncOperationWithProgress<IBuffer, uint> ReadAsync(IBuffer buffer, uint count, InputStreamOptions options)
{
    throw new NotImplementedException("To be done");
}

我的两个主要问题是:

我如何返回实现IAsyncOperationWithProgress的内容？框架中是否有任何内容可以帮助您呢？

如何将数据写入缓冲区？ IBuffer仅具有Length和Capacity属性(具体的Buffer类也不再提供)。

最佳答案

How to Convert byte Array to IRandomAccessStream

我已经找到了这篇博客文章，希望对IRandomAccessStream的这种了解可以成为您的起点。

class MemoryRandomAccessStream : IRandomAccessStream
{
    private Stream m_InternalStream;

    public MemoryRandomAccessStream(Stream stream)
    {
        this.m_InternalStream = stream;
    }

    public MemoryRandomAccessStream(byte[] bytes)
    {
        this.m_InternalStream = new MemoryStream(bytes);
    }

    public IInputStream GetInputStreamAt(ulong position)
    {
        this.m_InternalStream.Seek((long)position, SeekOrigin.Begin);

        return this.m_InternalStream.AsInputStream();
    }

    public IOutputStream GetOutputStreamAt(ulong position)
    {
        this.m_InternalStream.Seek((long)position, SeekOrigin.Begin);

        return this.m_InternalStream.AsOutputStream();
    }

    public ulong Size
    {
        get { return (ulong)this.m_InternalStream.Length; }
        set { this.m_InternalStream.SetLength((long)value); }
    }

    public bool CanRead
    {
        get { return true; }
    }

    public bool CanWrite
    {
        get { return true; }
    }

    public IRandomAccessStream CloneStream()
    {
        throw new NotSupportedException();
    }

    public ulong Position
    {
        get { return (ulong)this.m_InternalStream.Position; }
    }

    public void Seek(ulong position)
    {
        this.m_InternalStream.Seek((long)position, 0);
    }

    public void Dispose()
    {
        this.m_InternalStream.Dispose();
    }

    public Windows.Foundation.IAsyncOperationWithProgress<IBuffer, uint> ReadAsync(IBuffer buffer, uint count, InputStreamOptions options)
    {
        var inputStream = this.GetInputStreamAt(0);
        return inputStream.ReadAsync(buffer, count, options);
    }

    public Windows.Foundation.IAsyncOperation<bool> FlushAsync()
    {
        var outputStream = this.GetOutputStreamAt(0);
        return outputStream.FlushAsync();
    }

    public Windows.Foundation.IAsyncOperationWithProgress<uint, uint> WriteAsync(IBuffer buffer)
    {
        var outputStream = this.GetOutputStreamAt(0);
        return outputStream.WriteAsync(buffer);
     }
}