How to bind a List to a ComboBox?
C#WinformsData BindingComboboxC# Problem Overview
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
C# Solutions
Solution 1 - C#
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>
.
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.
Solution 2 - C#
For a backgrounder, there are 2 ways to use a ComboBox/ListBox
-
Add Country Objects to the Items property and retrieve a Country as Selecteditem. To use this you should override the ToString of Country.
-
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;
}
Solution 3 - C#
public MainWindow(){
List<person> personList = new List<person>();
personList.Add(new person { name = "rob", age = 32 } );
personList.Add(new person { name = "annie", age = 24 } );
personList.Add(new person { name = "paul", age = 19 } );
comboBox1.DataSource = personList;
comboBox1.DisplayMember = "name";
comboBox1.SelectionChanged += new SelectionChangedEventHandler(comboBox1_SelectionChanged);
}
void comboBox1_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
person selectedPerson = comboBox1.SelectedItem as person;
messageBox.Show(selectedPerson.name, "caption goes here");
}
boom.
Solution 4 - C#
Try something like this:
yourControl.DataSource = countryInstance.Cities;
And if you are using WebForms you will need to add this line:
yourControl.DataBind();
Solution 5 - C#
public class Country
{
public string Name { get; set; }
public IList<City> Cities { get; set; }
public Country()
{
Cities = new List<City>();
}
}
public class City
{
public string Name { get; set; }
}
List<Country> Countries = new List<Country>
{
new Country
{
Name = "Germany",
Cities =
{
new City {Name = "Berlin"},
new City {Name = "Hamburg"}
}
},
new Country
{
Name = "England",
Cities =
{
new City {Name = "London"},
new City {Name = "Birmingham"}
}
}
};
bindingSource1.DataSource = Countries;
member_CountryComboBox.DataSource = bindingSource1.DataSource;
member_CountryComboBox.DisplayMember = "Name";
member_CountryComboBox.ValueMember = "Name";
This is the code I am using now.
Solution 6 - C#
If you are using a ToolStripComboBox there is no DataSource exposed (.NET 4.0):
List<string> someList = new List<string>();
someList.Add("value");
someList.Add("value");
someList.Add("value");
toolStripComboBox1.Items.AddRange(someList.ToArray());