Warum funktioniert die ComboBox.SelectedValue-Binding-Kontext wird deaktiviert, wenn BindingList verpasst?

Ich habe einige Logik in die business-Schicht, die die Grenzen der ComboBox Optionen gemäß Eingänge, so muss ich ändern Sie die Werte in der zugrunde liegenden BindingList. Aber wenn die Liste verändert wird, die zwei-Wege-Bindung wird Einbahnstraße von der UI zur Einheit nur.

_mComboBox.DataBindings.Add("SelectedValue", _mEntity, "WifeCount");

Vollständigen code, mit dem problem-in die Schaltfläche "zuweisen" klicken Sie auf " handler:

using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace EnumDataBinding
{
    public partial class Form1 : Form
    {
        ComboBox _mComboBox = new ComboBox();
        Button _mCheckButton = new Button();
        Button _mAssignButton = new Button();

        BindingList<OptionValue> _mBindingList = new BindingList<OptionValue>();
        List<OptionValue> _mCacheList = new List<OptionValue>();

        Entity _mEntity = new Entity();

        public Form1()
        {
            InitializeComponent();

            //create a reset button
            _mCheckButton.Size = new Size(100, 30);
            _mCheckButton.Text = "Check";
            _mCheckButton.Location = new Point(100, 100);
            _mCheckButton.Click += new EventHandler(_mCheck_Click);

            //create assignment button
            _mAssignButton.Size = new Size(100, 30);
            _mAssignButton.Text = "Assign";
            _mAssignButton.Location = new Point(100, 135);
            _mAssignButton.Click += new EventHandler(_mAssignButton_Click);

            //create a combo box
            _mComboBox = new ComboBox();
            _mComboBox.Size = new System.Drawing.Size(300, 30);
            _mComboBox.Location = new Point(100, 200);

            this.Controls.AddRange(new Control[] {
                _mComboBox,
                _mCheckButton,
                _mAssignButton
            });

            //fill the bindinglist
            _mBindingList.Add(new OptionValue("One", 1M));
            _mBindingList.Add(new OptionValue("Two", 2M));
            _mBindingList.Add(new OptionValue("Three", 3M));

            _mCacheList.Add(new OptionValue("One", 1M));
            _mCacheList.Add(new OptionValue("Two", 2M));
            _mCacheList.Add(new OptionValue("Three", 3M));
        }

        void _mAssignButton_Click(object sender, EventArgs e)
        {
            //reset options
            _mBindingList.Clear();
            foreach (var o in _mCacheList)
                _mBindingList.Add(o);

            //EXPECTED: Update ComboBox.SelectedValue and ComboBox.Text
            //RESULT: Does not happen.
            _mEntity.WifeCount = 3M;

            this.Text = string.Format("SelectedValue: {0}; WifeCount: {1}", _mComboBox.SelectedValue, _mEntity.WifeCount);
        }

        private void PrepareComboBox(ComboBox combobox, BindingList<OptionValue> list)
        {
            combobox.DropDownStyle = ComboBoxStyle.DropDown;
            combobox.AutoCompleteSource = AutoCompleteSource.ListItems;
            combobox.AutoCompleteMode = AutoCompleteMode.Suggest;
            combobox.DataSource = new BindingSource() { DataSource = list };
            combobox.DisplayMember = "Display";
            combobox.ValueMember = "Value";
            combobox.Text = string.Empty;
            combobox.SelectedText = string.Empty;
        }

        protected override void OnLoad(EventArgs e)
        {
            //combo box datasource binding
            PrepareComboBox(_mComboBox, _mBindingList);

            //entity data binding
            _mComboBox.DataBindings.Add("SelectedValue", _mEntity, "WifeCount", false);

            base.OnLoad(e);
        }

        void _mCheck_Click(object sender, EventArgs e)
        {
            this.Text = string.Format("SelectedValue: {0}; WifeCount: {1}", _mComboBox.SelectedValue, _mEntity.WifeCount);
        }
    }

    public class Entity : INotifyPropertyChanged
    {
        decimal _mWifeCount;

        public decimal WifeCount { get { return _mWifeCount; } set { _mWifeCount = value; OnPropertyChanged("WifeCount"); } }

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public class OptionValue
    {
        string _mDisplay;
        object _mValue;

        public string Display { get { return _mDisplay; } set { _mDisplay = value; } }

        public object Value { get { return _mValue; } set { _mValue = value; } }

        public OptionValue(string display, object value)
        {
            _mDisplay = display;
            _mValue = value;
        }
    }
}

Update: Hinzufügen einer Ereignisprozedur für das Kombinationsfeld scheint zu funktionieren:

void _mComboBox_SelectedValueChanged(object sender, EventArgs e)
{
      var binding = (sender as Control).DataBindings["SelectedValue"];
      if (binding != null)
          binding.WriteValue();

      this.Text = string.Format("SelectedValue: {0}; WifeCount: {1}", _mComboBox.SelectedValue, _mEntity.WifeCount);
}