public override bool IsValid(object value, object container)
 {
     var model = (IGridViewItemWithAssetId)container;
     if (model.thumbnailAssetId <= 0)
     {
         return false;
     }
     CanFindLocationDatabaseContext db = new CanFindLocationDatabaseContext();
     Asset asset = await db.assets.FindAsync(model.thumbnailAssetId);
     if (asset == null)
     {
         return false;
     }
     return true;
 }
 public BaseController()
 {
     CanFindLocationDatabaseContext db = new CanFindLocationDatabaseContext();
 }