从ComboBox 2中删除从ComboBox 1中选择的项目

Question

I have two comboBoxes take the data from the same List witch contains an objects. How to remove the selected item in ComboBox 1 from items in ComboBox 2?

comboBox1.DataSource = CityList;    //CityList is list contain objects
comboBox1.ValueMember = "ID";
comboBox1.DisplayMember = "Name";

comboBox2.DataSource = CityList;
comboBox2.ValueMember = "ID";
comboBox2.DisplayMember = "Name";
comboBoxTargetState.Items.Remove(comboBoxCurrentState.SelectedItem); // give me an excption

Answer 1

When using DataSource , you have to remove the item from source instead from Items (because it's readonly when the ComboBox is data bound):

if(comboBoxCurrentState.SelectedIndex > -1)
  CityList.RemoveAt(comboBoxCurrentState.SelectedIndex);