MVVM-based data splitting from ViewModel

Question

I am new to WPF and MVVM, and so far I have an application that retrieves some ContactList objects from the DB2 database and displays their information in the user interface. Currently, I have a ContactListModel class and an InformationViewModel class that I am contacting. My InformationViewModel class is set as a DataContext for my view. The problem is that my InformationViewModel class also contains the ie db connection database access code and SQL command, and I would like to move this to my ContactListModel class so that I have a separate data access level. Can anyone help me with this? Thank!

ContactListModel.cs

public class ContactListModel//: INotifyPropertyChanged
{
    public int ContactListID { get; set; }
    public string ContactListName { get; set; }
    public ObservableCollection<AggregatedLabelModel> AggLabels { get; set; }
}

InformationViewModel.cs

public class InformationViewModel
{
    public InformationViewModel()
    {
        GetData();
    }

    private ObservableCollection<ContactListModel> myContactLists;

    public IEnumerable<ContactListModel> ContactLists
    {
        get { return myContactLists; }
    }


    public void GetData()
    {

        myContactLists = new ObservableCollection<ContactListModel>();

        DB2Connection conn = null;
        try
        {
            conn = new DB2Connection("SERVER CONNECTION;");
        }
        catch (Exception ex)
        {
            System.Windows.MessageBox.Show(ex.Message + " " + ex.InnerException);
        }

        //get all contactLists and their labels
        DB2Command command = new DB2Command("SELECT QUERY");
        command.Connection = conn;

        conn.Open();

        //Add unique contactLists to dictionary
        Dictionary<int, ContactListModel> myContactDictionary = new Dictionary<int, ContactListModel>();

        using (DB2DataReader dr = command.ExecuteReader())
        {
            while (dr.Read())
            {
                int id = Convert.ToInt32(dr["CONTACT_LIST_ID"]);

                if (!myContactDictionary.ContainsKey(id))
                {

                    ContactListModel contactList = new ContactListModel();

                    contactList.ContactListID = id;
                    contactList.ContactListName = dr["CONTACT_LIST_NAME"].ToString();
                    contactList.AggLabels = new ObservableCollection<AggregatedLabelModel>()
                {
                    new AggregatedLabelModel()
                    {
                        ID = Convert.ToInt32(dr["LABEL_ID"]),
                        Name = dr["LABEL_NAME"].ToString()
                    }

                };
                    myContactDictionary.Add(id, contactList);
                }
                else
                {
                    //populate existing contact lists with remaining labels
                    ContactListModel contactList = myContactDictionary[id];

                    contactList.AggLabels.Add
                    (
                        new AggregatedLabelModel()
                        {
                            ID = Convert.ToInt32(dr["LABEL_ID"]),
                            Name = dr["LABEL_NAME"].ToString()
                        }
                    );
                }
            }
        }
        conn.Close();
}

Answer 1

, SaveContact DeleteContact DataLayer.

    public class DataLayer
    {
        public ObservableCollection<ContactModel> GetContacts()
        {
            var tList = new ObservableCollection<ContactModel>();

            //load from db into tList

            return tList;
        }
    }

    public class ContactModel
    {
        public int ContactListID { get; set; }
        public string ContactListName { get; set; }
        public ObservableCollection<AggregatedLabelModel> AggLabels { get; set; }
    }

    public class ContactsViewModel
    {
        public ObservableCollection<ContactModel> ListOfContacts;

        public ContactsViewModel()
        {
            var dl = new DataLayer();
            ListOfContacts = dl.GetContacts();
        }
    }

Answer 2

:

• http://martinfowler.com/eaaCatalog/repository.html

• http://msdn.microsoft.com/en-us/library/ff649690.aspx

, , (, "-", "-" ) - , .

, , , , .

, , DTO, , , , .