将图像保存到Windows Phone 7中的媒体库

Question

我正在尝试将应用主页中名为image1的图像控件中的图像保存到手机的媒体库中，这是我的代码，但在WriteableBitmap中wr = image1; 这给了我一个错误。

public void SaveImageTo(string fileName = "Gage.jpg")
{
    fileName += ".jpg";
    var myStore = IsolatedStorageFile.GetUserStoreForApplication();
    if (myStore.FileExists(fileName))
    {
        myStore.DeleteFile(fileName);
    }

    IsolatedStorageFileStream myFileStream = myStore.CreateFile(fileName);
    WriteableBitmap wr = image1; // give the image source
    wr.SaveJpeg(myFileStream, wr.PixelWidth, wr.PixelHeight, 0, 85);
    myFileStream.Close();

    // Create a new stream from isolated storage, and save the JPEG file to the                               media library on Windows Phone.
    myFileStream = myStore.OpenFile(fileName, FileMode.Open, FileAccess.Read);
    MediaLibrary library = new MediaLibrary();
    //byte[] buffer = ToByteArray(qrImage);
    library.SavePicture(fileName, myFileStream); }

Answer 1

您试图将Control “ image1”分配给WriteableBitmap对象，这就是为什么您会出错（它们有2种不同的类型）的原因。

您应该根据如何设置“ image1”的来源来不同地初始化WriteableBitmap 。

如果“ image1”引用本地图像，则可以通过以下方式初始化相应的WriteableBitmap ：

BitmapImage img = new BitmapImage(new Uri(@"images/yourimage.jpg", UriKind.Relative));
img.CreateOptions = BitmapCreateOptions.None;
img.ImageOpened += (s, e) =>
{
    WriteableBitmap wr = new WriteableBitmap((BitmapImage)s);
};

如果要将图像控件呈现为WriteableBitmap，则可以执行以下操作：

WriteableBitmap wr = new WriteableBitmap(image1, null);