Writing an Image to SQL CE / Linq to SQL

Here is a short few steps I used to write an image to a SQL CE database on Windows Phone 7. As you may know Windows Phone 7.5 Mango supports SQL CE which makes it very convenient to store data in a proper relational database on the phone.

Creating the Column

 

There is some excellent help how to create your first SQL CE database which can be found here: http://msdn.microsoft.com/en-us/library/hh286405(v=VS.92).aspx

To create the column add the following code to your [Table] class:

[Column]
        public byte[] ItemImage
        {
            get { return _ItemImage; }
            set
            {
                if (_ItemImage != value)
                {
                    _ItemImage = value;
                    NotifyPropertyChanging(“ItemImage”);
                    NotifyPropertyChanged(“ItemImage”);
                }
            }
        }

Method for Adding the Image to the your Database

 

This method will take the stream you pass from your CameraCaptureTask and convert it to a byte array that can be saved in your database:

private byte[] GetImageBytes(Stream stream)
        {
            using (MemoryStream ms = new MemoryStream())
            {
                WriteableBitmap wb = PictureDecoder.DecodeJpeg(stream, 200, 200);
                wb.SaveJpeg(ms, 200, 200, 0, 30);
                return ms.ToArray();
            }
        }

public void AddNewItem(Stream image, string url)
        {
            //Get Byte array of Image
            byte[] byteArray = GetImageBytes(image);

            //Add Image to Database
            MyDatabaseItem item = new MyDatabaseItem { Count = 1, ItemImageUrl = url, ItemImage = byteArray };
            MyDatabaseItemModel.Add(item);
            MyDatabaseDB.MyDatabaseItems.InsertOnSubmit(item);
            MyDatabaseDB.SubmitChanges();
        }

Showing the Image from your database in XAML

 

You need to make use of a converter that convert the byte array to a BitmapImage, here is the code for the converter you can use:

public class ImageConverter: IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (value is byte[])
            {
                MemoryStream memoryStream = new MemoryStream(value as byte[]);
                WriteableBitmap writeBitmap = PictureDecoder.DecodeJpeg(memoryStream, 200, 200);
                return writeBitmap;
            }
            else
                return null;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

And then you will need to call the converter in your Image XAML:

<Image Source="{Binding ItemImage, Converter={StaticResource ImageConverter}}" Stretch="UniformToFill"/>