WPF Combobox isn't visible in View while using MVVM pattern

Question

I create a wpf project using MVVM patern. In View, when I start a project, I haven't seen any items in ComboBoxes and Labels, though I see items in DataContext in ObservableCollection, when debugging. What could be wrong with Binding in my code?

My XAML code:

<ItemsControl ItemsSource="{Binding Items}" >
        <ItemsControl.ItemTemplate>
            <DataTemplate>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="*"  />
                        <ColumnDefinition Width="*"  />
                    </Grid.ColumnDefinitions>
                    <Label  Content="{Binding Name}" Grid.Column="0" Height="26" Width="105" Margin="5,5,0.2,0"/>
                    <ComboBox  ItemsSource="{Binding ComboBoxItems}" Grid.Column="1" />
                </Grid>
            </DataTemplate>
        </ItemsControl.ItemTemplate>
    </ItemsControl>

XAML.cs code:

this.DataContext = new ViewModel();
InitializeComponent();

ViewModel.cs code:

public ObservableCollection<Model> Items;
public ViewModel()
    {
        Items = new ObservableCollection<Model>();
        Items.Add(new Model { Name = "111111" });
        Items.Add(new Model { Name = "222222" });
        Items.Add(new Model { Name = "444444" });
        Items.Add(new Model { Name = "333333" });
    }

Model code:

    public class Model : INotifyPropertyChanged
        {
    public ObservableCollection<string> ComboBoxItems;

    public Model()
            {
                   ComboBoxItems =new ObservableCollection<string>();
                   ComboBoxItems.Add("111111");
                   ComboBoxItems.Add("222222");
                   ComboBoxItems.Add("444444");
                   ComboBoxItems.Add("333333");
            }
private string _name;
    public string Name
            {
                get { return _name; }
               set
               {
                  _name= value;
                  OnPropertyChanged("Name");
               }
            }
    public void OnPropertyChanged([CallerMemberName]string prop = "")
            {
                if (PropertyChanged != null)
                    PropertyChanged(this, new PropertyChangedEventArgs(prop));
            }
  public event PropertyChangedEventHandler PropertyChanged;
       }

Your ComboBoxItems is not a public property. You need a public property to bind. — Andy, Apr 12 '19 at 13:22

score 1 · Accepted Answer · answered Apr 12 '19 at 13:26

You need properties for binding to work.

Change your variable

 public ObservableCollection<string> ComboBoxItems;

To a property

 public ObservableCollection<string> ComboBoxItems {get;set;}

Similarly Items

public ObservableCollection<Model> Items;

To

  public ObservableCollection<Model> Items  {get;set;}

You might want to make these propfull and raise property changed in the setter.

But properties have getter and setters.

Variables do not, and will not bind.

Thank you very much for reply! – user253105 Apr 12 '19 at 13:35 — user253105, Apr 12 '19 at 13:35

WPF Combobox isn't visible in View while using MVVM pattern

1 Answers1