How to save an item from a ComboBox

Question

Hello. Tell me how can I make the ability to save the selected element of the ComboBox. I have 2 comboBox, second comboBox works based on item selection from 1 ComboBox. Both ComboBoxes are in 1 form.

Answer 1

Hi,@vitaminchik. Welcome Microsoft Q&A. For the second ComboBox to display data according to the SelectedItem of the first ComboBox, you could refer to the following code.

MainWindow.xaml:

 <Window.DataContext>
        <local:ViewModel/>
    </Window.DataContext>
    <StackPanel Orientation="Horizontal">
        <StackPanel>
            <TextBlock Text="Categories" Width="100"/>
            <ComboBox ItemsSource="{Binding Categories}"   Width="100"  Height="50" DisplayMemberPath="Name"  SelectedItem="{Binding SelectedCategory}" />
        </StackPanel>
        <StackPanel>
            <TextBlock Text="Proucts" Width="100"/>
            <ComboBox ItemsSource="{Binding Proucts}" Width="100"  Height="50"  DisplayMemberPath="Name"  SelectedItem="{Binding SelectedProduct}"   />
        </StackPanel>
       
    </StackPanel>

MainWindow.xaml.cs:

 public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }
    public class Category
    {
        public string Name {  get; set;  }
        public ICollection<Product> Proucts {    get;  set; }
    }

    public class Product
    {
        public string Name { get; set; }
        public Category Category {  get;set; }
    }
    public class ViewModel : INotifyPropertyChanged
    {
        public ViewModel()
        {
            this.Categories = new ObservableCollection<Category>() 
            { new Category(){ Name = "Vegetables", Proucts = new ObservableCollection<Product>() {  new Product(){ Name = "Carrot" }, new Product(){ Name = "Tomato" }, new Product(){ Name = "Potato" }  }},
              new Category(){ Name = "Fruit",  Proucts = new ObservableCollection<Product>()  { new Product(){ Name = "Apple" }, new Product(){ Name = "Banana" }, new Product(){ Name = "Pear" } }},
              new Category(){ Name = "Seafood", Proucts = new ObservableCollection<Product>() { new Product(){ Name = "Lobster" }, new Product(){ Name = "Crab" }, new Product(){ Name = "Scallop" }}}
            };
            this.Proucts = new ObservableCollection<Product>();
            this.SelectedCategory = this.Categories[0];
        }
        public ObservableCollection<Category> Categories {  get;  private set;   }
        public ObservableCollection<Product> Proucts { get; private set; }
       
        private Category _selectedCategory;
        public Category SelectedCategory
        {
            get
            {
                return _selectedCategory;
            }
            set
            {
                _selectedCategory = value;
                this.Proucts.Clear();
                foreach (Product product in _selectedCategory.Proucts)
                    this.Proucts.Add(product);
            }
        }
        public Product SelectedProduct { get; set; }

        public event PropertyChangedEventHandler PropertyChanged;
        private void OnPropertyChanged(string name)
        {
            PropertyChangedEventHandler handler = PropertyChanged;
            if (handler != null)
                handler(this, new PropertyChangedEventArgs(name));
        }
    }

The result:

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