尝试将图像保存到Windows Phone 8中的媒体库时出现异常

Question

在尝试保存图像MediaLibrary时,我收到以下错误

Microsoft.Xna.Framework.ni.dll中出现"System.InvalidOperationException"类型的异常,但未在用户代码中处理

这是我正在使用的代码

if (SourceImage != null) // Source Image is WriteableBitmap
{
    var imageArray = SourceImage.ToByteArray(); // WriteableBitmapExWinPhone (extension method)
    var res = await SavePhotoToImageHub(imageArray);
    await ShowMessage(res ? AppResources.MEDIA_LIBRARY_SUCCESS_MESSAGE :  AppResources.MEDIA_LIBRARY_FAILURE_MESSAGE);
}

使用的方法是

private Task<bool> SavePhotoToImageHub(byte[] imageArray)
{
    using (var mediaLibrary = new MediaLibrary())
    {
        var fileName = string.Format("Gs{0}.jpg", Guid.NewGuid());
        var picture = mediaLibrary.SavePicture(fileName, imageArray);
        if (picture.Name.Contains(fileName)) return Task.FromResult(true);
    }

    return Task.FromResult(false);
}

我也试过流而不是字节数组.

Answer 1

您需要检查的第一件事是您是否已将ID_CAP_MEDIALIB_PHOTO添加到您的应用清单中.

第二件事是流 - 您尝试将其重置为开头吗？这个方法对我有用:

private bool SavePhotoToImageHub(WriteableBitmap bmp)
    {

        using (var mediaLibrary = new MediaLibrary())
        {
            using (var stream = new MemoryStream())
            {
                var fileName = string.Format("Gs{0}.jpg", Guid.NewGuid());
                bmp.SaveJpeg(stream, bmp.PixelWidth, bmp.PixelHeight, 0, 100);
                stream.Seek(0, SeekOrigin.Begin);
                var picture = mediaLibrary.SavePicture(fileName,stream);
                if (picture.Name.Contains(fileName)) return true;
            }
        }
        return false;
    }