There are two ways to fill the ComboBox and ListBox controls.
For example, you can add objects to the ComboBox by using the Add method. You can also add objects to a ComboBox by using the DataSource, DisplayMember, and ValueMember properties to fill the ComboBox.
When the DataSource property is set, a user cannot modify the items collection.
If setting the DataSource property causes the data source to change, the DataSourceChanged event is raised. If setting this property causes the data member to change, the DisplayMemberChanged event is raised.
When you set DataSource to a null reference (Nothing in Visual Basic), DisplayMember is set to an empty string ("").