Local DB throws Byte array truncation to a length

问题:

I'm trying to take a snapshot from a Map control as a WritableBitmap, convert it to a byte array and save it in the local DB. It works fine (I can convert the byte array back to the image) untill I submit the changes to the DB. At this point it throws an exception "Byte array truncation to a length of 8000". I didn't find any documentation about byte array limitation. Does anyone know how to increase the limit of 8000? My byte array is a member of my Model:

private byte[] _locationImage;
[Column]
public byte[] LocationImage
{
   get { return _locationImage; }
   set
   {
      if (_locationImage != value)
      {
         NotifyPropertyChanging("LocationImage");
         _locationImage = value;
         NotifyPropertyChanged("LocationImage");
      }
   }
}

回答1:

If you look at the SQL Compact docs, you'll see that a binary or varbinary field can be at most 8000 bytes, so that tells me that a byte[] column gets mapped to varbinary. To get it to store data larger than that, you'd need to get the engine to use an image field type. This might be as simple as updating the Column attribute like this (untested):

[Column(DbType="image")]
public byte[] LocationImage { ... }