c# – 我无法使用BitmapImage初始化WriteableBitmap

BitmapImage img = new BitmapImage(new Uri("somepath",UriKind.Relative));
 WriteableBitmap wbm = new WriteableBitmap(img);

我在上面的行中得到一个运行时错误：“对象引用未设置为对象的实例”.

解决方法

获取空引用异常的原因是 BitmapImage.CreateOptions Property默认值为BitmapCreateOptions.DelayCreation.您可以将其设置为BitmapCreateOptions.None并在加载图像后创建WriteableBitmap：

BitmapImage img = new BitmapImage(new Uri("somepath",UriKind.Relative));
img.CreateOptions = BitmapCreateOptions.None;
img.ImageOpened += (s,e) =>
   {
       WriteableBitmap wbm = new WriteableBitmap((BitmapImage)s);
   };