How to bind a List to a ComboBox?

Question

I want to connect a BindingSource to a list of class objects and then objects value to a ComboBox.
Can anyone suggest how to do it?

public class Country {     public string Name { get; set; }     public IList<City> Cities { get; set; }      public Country()     {         Cities = new List<City>();     } } 

is my class and I want to bind its name field to a BindingSource which could be then associated with a ComboBox

Answer 1

As you are referring to a combobox, I'm assuming you don't want to use 2-way databinding (if so, look at using a BindingList)

public class Country {     public string Name { get; set; }     public IList<City> Cities { get; set; }     public Country(string _name)     {         Cities = new List<City>();         Name = _name;     } } 

List<Country> countries = new List<Country> { new Country("UK"),                                       new Country("Australia"),                                       new Country("France") };  var bindingSource1 = new BindingSource(); bindingSource1.DataSource = countries;  comboBox1.DataSource = bindingSource1.DataSource;  comboBox1.DisplayMember = "Name"; comboBox1.ValueMember = "Name"; 

To find the country selected in the bound combobox, you would do something like: Country country = (Country)comboBox1.SelectedItem;.

If you want the ComboBox to dynamically update you'll need to make sure that the data structure that you have set as the DataSource implements IBindingList; one such structure is BindingList<T>.

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Tip: make sure that you are binding the DisplayMember to a Property on the class and not a public field. If you class uses public string Name { get; set; } it will work but if it uses public string Name; it will not be able to access the value and instead will display the object type for each line in the combo box.

Answer 2

For a backgrounder, there are 2 ways to use a ComboBox/ListBox

1) Add Country Objects to the Items property and retrieve a Country as Selecteditem. To use this you should override the ToString of Country.

2) Use DataBinding, set the DataSource to a IList (List<>) and use DisplayMember, ValueMember and SelectedValue

For 2) you will need a list of countries first

// not tested, schematic: List<Country> countries = ...; ...; // fill   comboBox1.DataSource = countries; comboBox1.DisplayMember="Name"; comboBox1.ValueMember="Cities"; 

And then in the SelectionChanged,

if (comboBox1.Selecteditem != null) {    comboBox2.DataSource=comboBox1.SelectedValue;  }