WPFコントロール：ComboBox（ドロップダウン選択）

<ComboBox Name="MyCombo"
                Width="150"
                Height="30"
                SelectionChanged="MyCombo_SelectionChanged">

        <ComboBoxItem Content="Apple"/>
        <ComboBoxItem Content="Banana"/>
        <ComboBoxItem Content="Orange"/>

</ComboBox>

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }
    private void MyCombo_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if (MyCombo.SelectedItem is ComboBoxItem item)
        {
            if (item.Content is not null)
            {
                string? text = item.Content.ToString();
                MessageBox.Show($"選択: {text}");            
                
            }
        }

    }
}