重构WPF代码

Question

I have a method called get Data which executes my SQL and returns some rows of ContactLists containing Aggregated Labels.At the moment this method is in my code behind and would like to move it to a separate Data Access class. I would appreciate your assistance. Thanks!

Answer 1

Is normal, if i understand your code, you do this operation after ContactList initialization:

contactList.Labels = new ObservableCollection<Label>()
{ 
   new Label() { 
      Name = dr["LABEL_NAME"].ToString(), 
       Count = Convert.ToInt32(dr["LABEL_COUNT"]) 
   } 
};

For each ContactList is always added one item, you will do something like this:

contactList.Labels = new ObservableCollection<Label>();
foreach(var item in <yourLabelDataSource>)
    contactList.Labels.Add(new Label(...));

The solution is like this:

    Dictionary<int, ContactList> myContactDictionary = new Dictionary<int, ContactList>();

    using (DB2DataReader dr = command.ExecuteReader())
    {

        while (dr.Read())
        {

            int id = Convert.ToInt32(dr["CONTACT_LIST_ID"]);
            if (!myContactDictionary.ContainsKey(id))
            {

                ContactList contactList = new ContactList();

                contactList.ContactListID = id;
                contactList.ContactListName = dr["CONTACT_LIST_NAME"].ToString();

                contactList.Labels = new ObservableCollection<Label>() 
                { 
                    new Label() 
                    { 
                        Name = dr["LABEL_NAME"].ToString(), 
                        Count = Convert.ToInt32(dr["LABEL_COUNT"]) 
                    } 
                };

                myContactDictionary.Add(id, contactList);
            }

            else 
            {
                //Add new label because CONTACT_LIST_ID Exists 
                ContactList contactList = myContactDictionary[id];
                contactList.Labels.Add(
                    new Label()
                        {
                            Name = dr["LABEL_NAME"].ToString(), 
                            Count = Convert.ToInt32(dr["LABEL_COUNT"])                                         
                        }
                    );
            }

        }
    }

Ben, for your last question you can use this solution:

            else 
            {
                //Add new label because CONTACT_LIST_ID Exists 
                ContactList contactList = myContactDictionary[id];
                string name = dr["LABEL_NAME"].ToString();
                var label = contactList.Labels.Where(l => l.Name == name).FirstOrDefault();
                if( label != null )
                    label.Count += Convert.ToInt32(dr["LABEL_COUNT"]);
                else
                {
                    contactList.Labels.Add(
                        new Label()
                        {
                            Name = dr["LABEL_NAME"].ToString(), 
                            Count = Convert.ToInt32(dr["LABEL_COUNT"])                                         
                        }
                    );
                }

I hope this code is readable and helpfulL! }

This is other response:

1. Create and Object Model that can contain your required data:

    public class DataResult { public ObservableCollection<AggregatedLabel> AggregatedLabels { get; set; } public ObservableCollection<ContactList> ContactLists { get; set; } } 

2. You can build a method that return DataResult object, in your method (GetData()), you can valorize the two different properties (AggregatedLabels and ContactsList) with your DB Result. In the and you can return DataResult Object.

A little example here:

public DataResult GetData()
{
   DataResult result = new DataResult();
   result.AggregatedLabels = new ObservableCollection<AggregatedLabel>();
   result.ContactLists = new ObservableCollection<ContactList>();

   // Manipulate data result with your method logic like in this examle:
   foreach(var something in dbResult)
   {
       ContactList cl = new ContactList() { 
       //Binding from something
       }
       result.ContactLists.Add(cl);
   }
   return result; //return your Object Model with required Data!
}

I hope it is conceptually clear