当我更改combobox1时，它也会同时更改combobox2中的值（都使用相同的List）

Question

I've 2 combobox on my winform. Both comboboxes are loaded by the list below. Everything works fine. Except, when I change a value in Combobox1 then it also changes the value in combobox2... and the same for other combobox. When I change a value in combobox 2 it changes in combobox1....

Both have to use the same list of values. so that's the reason why I just bind to the same list (_item).

so what do I need to do to decouple the 2 comboboxes from each other?

   IList<CompteGeneral> _item = new List<CompteGeneral>(compt_repository.GetAll);
            combobox1.DataSource = _item;
            combobox1.DisplayMember = "AccountNumber";

            combobox2.DataSource = _item;
            combobox2.DisplayMember = "AccountNumber";

Answer 1

IList<CompteGeneral> _item = new List<CompteGeneral>(compt_repository.GetAll);
IList<CompteGeneral> _item1 = new List<CompteGeneral>(compt_repository.GetAll);
combobox1.DataSource = _item;
combobox1.DisplayMember = "AccountNumber";

combobox2.DataSource = _item1;
combobox2.DisplayMember = "AccountNumber";

or

IList<CompteGeneral> _item = new List<CompteGeneral>(compt_repository.GetAll);
BindingSource source=new BindingSource();
source.DataSource=_item ;
BindingSource source1=new BindingSource();
source1.DataSource=_item ;


combobox1.DataSource = source;
combobox1.DisplayMember = "AccountNumber";

combobox2.DataSource = source1;
combobox2.DisplayMember = "AccountNumber";

example

Answer 2

Create a new List with the same item by passing the _item1 in the constructor.

Assign the new list to the second Combobox.

        IList<CompteGeneral> _item1 = new List<CompteGeneral>(compt_repository.GetAll);

        IList<CompteGeneral> _item2 = new List<CompteGeneral>(_item1);

        combobox1.DataSource = _item1;
        combobox1.DisplayMember = "AccountNumber";

        combobox2.DataSource = _item2;
        combobox2.DisplayMember = "AccountNumber";

Answer 3

implement the Clone method from ICloneable interface on CompteGeneral

  IList<CompteGeneral> _item = new List<CompteGeneral>(compt_repository.GetAll);
            combobox1.DataSource = _item;
            combobox1.DisplayMember = "AccountNumber";

            combobox2.DataSource = _item.Select(p => p.Clone()).ToList();
            combobox2.DisplayMember = "AccountNumber";

Also search for ShallowCopy and DeepCopy paradigms when cloning objects.