Question

我即将为COM互操作IStream编写一个Wrapper，以便需要标准.NET Stream的代码可以使用它。

然而，我发现这种事情之前可能已经完成了（尽管我自己也没能通过网络搜索找到它）。

所以我只是把它放在这里以防万一我要重新发明轮子。

注意我遇到了实现IStream包装.NET流的代码，但我需要反过来。

Answer 1

确实如此，System.Runtime.InteropServices.ComTypes.IStream。样本包装器：

using System;
using iop = System.Runtime.InteropServices;
using System.Runtime.InteropServices.ComTypes;

public class ComStreamWrapper : System.IO.Stream {
  private IStream mSource;
  private IntPtr mInt64;

  public ComStreamWrapper(IStream source) { 
    mSource = source;
    mInt64 = iop.Marshal.AllocCoTaskMem(8);
  }

  ~ComStreamWrapper() { 
    iop.Marshal.FreeCoTaskMem(mInt64); 
  }

  public override bool CanRead { get { return true; } }
  public override bool CanSeek { get { return true; } }
  public override bool CanWrite { get { return true; } }

  public override void Flush() { 
    mSource.Commit(0); 
  }

  public override long Length { 
    get { 
      STATSTG stat;
      mSource.Stat(out stat, 1);
      return stat.cbSize;
    }
  }

  public override long Position {
    get { throw new NotImplementedException(); }
    set { throw new NotImplementedException(); }
  }

  public override int Read(byte[] buffer, int offset, int count) {
    if (offset != 0) throw new NotImplementedException();
    mSource.Read(buffer, count, mInt64);
    return iop.Marshal.ReadInt32(mInt64);
  }

  public override long Seek(long offset, System.IO.SeekOrigin origin) {
    mSource.Seek(offset, (int)origin, mInt64);
    return iop.Marshal.ReadInt64(mInt64);
  }

  public override void SetLength(long value) {
    mSource.SetSize(value);
  }

  public override void Write(byte[] buffer, int offset, int count) {
    if (offset != 0) throw new NotImplementedException();
    mSource.Write(buffer, count, IntPtr.Zero);
  }
}

是否存在COM互操作IStream的包装类？

1 个答案: