ComboBox binding to Items Collection

[Gary C]

Hello,

We are upgrading to the latest version of the WinForms components. I see there have been changes to the binding logic. I have a RadComboBox and I'm binding a list to it. If I create the combo dynamically and assign my list to the datasource property the Items collection is not bound (Items.Count = 0) until I assign the combo box to a container.

Is there a way to force this sooner without requiring a parent component? In this case our combo box is in a grid with an image associated with each item in the list so we are doing some initialization and need the items to be there for this.

Thanks,

-Gary

Here is some code to demonstrate the problem:

    public partial class Form1 : Form
    {
        const string DISPLAY_FIELD = "Name";
        const string VALUE_FIELD = "ID";
        public Form1()
        {
            InitializeComponent();
        }

        private void radButton2_Click(object sender, EventArgs e)
        {
            List<ComboItems> comboItems = new List<ComboItems>(3);

            comboItems.Add(new ComboItems("Red", 1));
            comboItems.Add(new ComboItems("White", 2));
            comboItems.Add(new ComboItems("Blue", 3));

            RadComboBox rcb = new RadComboBox();
            rcb.DisplayMember = DISPLAY_FIELD;
            rcb.ValueMember = VALUE_FIELD;
            rcb.DataSource = comboItems;

            // rcb.Items.Count == 0 at this point
            rcb.Parent = this;

            // now rcb.Items.Count == 3
        }
    }

    public class ComboItems
    {
        public string Name { get; set; }
        public int ID { get; set; }

        public ComboItems(string displayMember, int valueMember)
        {
            Name = displayMember;
            ID = valueMember;
        }

    }

[Victor]

Hello Gary C,

Thank you for your question. The reason why RadComboBox is not being bound is that it does not have a BindingContext object until it is added to a container and the form on which the container resides is shown. You can force RadComboBox to bind itself when you assign a BindingContext explicitly, for example:

rcb.BindingContext = new BindingContext();

Please write again if you need further assistance.

Regards,
Victor
the Telerik team

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