从SQLite数据库在DataGridViewImageColumn[WinForm]中显示图像

I have a sqlite db from where i am retrieving images. I have to display those images into a windows datagrid. For binding , I have Class Called COntacts , given below

namespace ContactManager.Core
{
    public class Contacts
    {
        private long _id = 0;

        public long Id
        {
            get { return _id; }
            set { _id = value; }
        }
        private string _Name = string.Empty;

        public string Name
        {
            get { return _skypeName; }
            set { _skypeName = value; }
        }
        private string _displayName = string.Empty;

        public string DisplayName
        {
            get { return _displayName; }
            set { _displayName = value; }
        }
        private long _birthday = 0;

        public long BirthDay
        {
            get { return _birthday; }
            set { _birthday = value; }
        }

        private string _province = string.Empty;

        public string Province
        {
            get { return _province; }
            set { _province = value; }
        }
        private long _phone_home = 0;

        public long Phone_Home
        {
            get { return _phone_home; }
            set { _phone_home = value; }
        }
        private long _phone_mobile = 0;

        public long Phone_Mobile
        {
            get { return _phone_mobile; }
            set { _phone_mobile = value; }
        }

        private string _mood_text = string.Empty;

        public string Mood_Text
        {
            get { return _mood_text; }
            set { _mood_text = value; }
        }

       private byte[] _avatar_image = new byte[4096];
       public byte[] Avatar_Image
       {
           get{return _avatar_image;}
           set{_avatar_image = value;}
       }


    }
}

所以我的第一个问题是,我应该在这个contact类中创建什么类型的属性来保存图像数据。 我正在运行时创建DataGridViewColumns。代码如下

DataGridViewImageColumn dgvImColAvatar = new DataGridViewImageColumn();
dgvImColAvatar.AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill;
dgvImColAvatar.HeaderText = "Avatar";
dgvImColAvatar.DataPropertyName = "Avatar";

but when I execute application it shows me some TargetInvocation exeception with NullReference Exception too. 所以请帮助我从数据库中检索图像数据,并使用类、属性和集合绑定它。在它们之间我正在使用 MapperBase<T> 自动为属性赋值。