使用WriteableBitmapEx访问像素颜色时的AccessViolationException

Question

我正在使用WriteableBitmapEx库编辑用Windows8专业版平板电脑的摄像头拍摄的图像。每次我调用GetPixel()函数时都会得到一个AccessViolationException，下面是代码：

Windows.Media.Capture.MediaCapture captureMgr = new MediaCapture();
await captureMgr.InitializeAsync();

IRandomAccessStream memoryStream = new InMemoryRandomAccessStream();
await captureMgr.CapturePhotoToStreamAsync(imageProperties, memoryStream);
await memoryStream.FlushAsync();
memoryStream.Seek(0);

WriteableBitmap tmpImage = new WriteableBitmap(1, 1); 
tmpImage.SetSource(memoryStream);
tmpImage.GetPixel(1, 1); // An AccessViolationException occurs.

我哪里做错了？

Answer 1

尝试使用内置方法来创建您的WriteableBitmap。

WriteableBitmap tmpImage = await BitmapFactory.New(1, 1).FromStream(memoryStream);  
tmpImage.GetPixel(1, 1);

这将确保您的映像在被访问之前已加载到WriteableBitmap中。