使用BitmapImage.BeginInit（）时未捕获ArgumentException

try
{
Uri myUri = new Uri(\"http://example.com/image.jpg\", UriKind.RelativeOrAbsolute);
JpegBitmapDecoder decoder2 = new JpegBitmapDecoder(myUri,
                             BitmapCreateOptions.PreservePixelFormat,
                             BitmapCacheOption.Default);
BitmapSource bitmapSource2 = decoder2.Frames[0];
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}

try
{
BitmapImage src = new BitmapImage();
src.BeginInit();
src.UriSource = new Uri(\"http://example.com/image.jpg\");
src.EndInit();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}

src.CacheOption = BitmapCacheOption.OnLoad;