我正在构建一个 WPF 桌面应用程序来帮助我组织照片以发布到 Facebook。以下是我在新位置创建照片副本并添加标题(EXIF + IPTC + XMP)的代码:
private void SaveImageAs(string currPath, string newPath, bool setCaption = false, string captionToSet = "")
{
System.IO.FileStream stream = new System.IO.FileStream(currPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
JpegBitmapDecoder decoder = new JpegBitmapDecoder(stream, BitmapCreateOptions.None, BitmapCacheOption.None);
BitmapFrame bitmapFrame = decoder.Frames[0];
BitmapMetadata metadata = bitmapFrame.Metadata.Clone() as BitmapMetadata;
stream.Close();
if (setCaption)
{
// if we want to set the caption, do it in EXIF, IPTC, and XMP
metadata.SetQuery("/app1/ifd/{uint=270}", captionToSet);
metadata.SetQuery("/app13/irb/8bimiptc/iptc/Caption", captionToSet);
metadata.SetQuery("/xmp/dc:description/x-default", captionToSet);
}
MemoryStream memstream = new MemoryStream(); // create temp storage in memory
JpegBitmapEncoder encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bitmapFrame, bitmapFrame.Thumbnail, metadata, bitmapFrame.ColorContexts));
encoder.Save(memstream); // save in memory
stream.Close();
stream = new FileStream(newPath, FileMode.OpenOrCreate, FileAccess.Write, FileShare.ReadWrite);
memstream.Seek(0, System.IO.SeekOrigin.Begin); // go to stream start
byte[] bytes = new byte[memstream.Length + 1];
memstream.Read(bytes, 0, (int)memstream.Length);
stream.Write(bytes, 0, bytes.Length);
stream.Close();
memstream.Close();
}
运行该程序,我得到一个“COMException was unhandled”异常,突出显示了这一行:
encoder.Save(memstream);
类型为“System.Runtime.InteropServices.COMException”的未处理异常发生在
演示核心.dll
附加信息:句柄无效。 (HRESULT 异常:0x80070006 (E_HANDLE))
I saw here这可能是由于线程问题造成的,因此我没有直接从应用程序调用 SaveImageAs,而是添加了以下内容,但没有效果:
private void _SaveImageAs(string currPath, string newPath, bool setCaption = false, string captionToSet = "")
{
Thread saveThread = new Thread(() => SaveImageAs(currPath, newPath, setCaption, captionToSet));
saveThread.SetApartmentState(ApartmentState.STA);
saveThread.IsBackground = false;
saveThread.Start();
}
我还尝试将 MemoryStream 替换为 FileStream 创建本地临时文件 - 这没有改变任何内容:
FileStream memstream = new FileStream(System.IO.Path.GetDirectoryName(newPath) + @"\" + "temp.jpg", System.IO.FileMode.OpenOrCreate);
有任何想法吗?