How to Bind a List of Custom Objects to a ComboBox and Retrieve the Selected Item?

Bind a list of objects to a combo box option

You need a solution to bind a custom object list to a combobox and display its specified properties as option labels. As background, consider the following classes:

<code class="language-c#">public class Country
{
    public string Name { get; set; }
    public IList<City> Cities { get; set; }

    public Country()
    {
        Cities = new List<City>();
    }
}</code>

Step-by-step guide

To create a binding, follow these steps:

1. Create a List of custom objects (e.g., Country):

   <code class="language-c#"> List<Country> countries = new List<Country> { new Country { Name = "UK" }, new Country { Name = "Australia" }, new Country { Name = "France" } };</code>

2. Initialize a BindingSource and assign its DataSource to List:

   <code class="language-c#"> var bindingSource1 = new BindingSource();
    bindingSource1.DataSource = countries;</code>

3. Set the DataSource of the combo box to the DataSource of the BindingSource:

   <code class="language-c#"> comboBox1.DataSource = bindingSource1.DataSource;</code>

4. Specify the property to be displayed in the combo box as DisplayMember:

   <code class="language-c#"> comboBox1.DisplayMember = "Name";</code>

5. Specifies that the value returned by the combo box will use the property as ValueMember:

   <code class="language-c#"> comboBox1.ValueMember = "Name";</code>

Retrieve selected items

To get the selected Country object from a combo box, cast its selected items to the corresponding type:

<code class="language-c#">Country selectedCountry = (Country)comboBox1.SelectedItem;</code>

Dynamic updates

If you need the combo box to update automatically, make sure the DataSource implements the IBindingList interface. BindingList is an implementation that supports real-time data changes.

Display objects and properties

Note that DisplayMember should reference a property in the class (e.g., "Name"). If you use a field (for example, "Name;"), the value will not be accessible and the combo box will display the object type instead of the property value.

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