How to Iterate listview items using MVMV

Question

Can someone help and show me how to iterate ListView items using MVVM?

In the Code Behind it is done as follows:

for (int i = 0; i < NameOfListView.Items.Count; i++)
{
//code
}

In MVVM unfortunately I don't know how to address the ListView.
The goal is to iterate over all items/rows and store the content in a list.

Answer

I'm not sure what kind of iteration effect you want. You could take a look at the example below. Any questions please let me know.
MainWindow.xaml:

MainWindow.xaml.cs:

using System.Collections.ObjectModel;  
using System.ComponentModel;  
using System.Runtime.CompilerServices;  
using System.Windows;  
  
namespace ListViewIterate  
{  
  public partial class MainWindow : Window  
  {  
    public MainWindow()  
    {  
      InitializeComponent();  
      DataContext =new ViewModel();  
    }  
    public ObservableCollection DGItems;  
    public void test()  
    {  
       ObservableCollection items = (ObservableCollection)MColumnsListXaml.ItemsSource;  
   
  foreach (var item in items)  
  {  
    DGItems = new ObservableCollection();  
    
    item.MColumnName="item";  
    DGItems.Add(item);  
    tb.Text = item.ToString();  

  }  
  dg.ItemsSource = items;  
    }  
  
    private void btn_Click(object sender, RoutedEventArgs e)  
    {  
      test();  
    }  
  }  
  public class ViewModel : INotifyPropertyChanged  
  {  
    private ObservableCollection mColumnsList;  
    public ObservableCollection MColumnsList  
    {  
      get { return mColumnsList;}  
      set { mColumnsList=value; OnPropertyChanged("MColumnsList");}  
    }  
    public ViewModel()  
    {  
       MColumnsList = new ObservableCollection();  
      MColumnsList.Add(new MandatoryColumns() { MColumnName = "John", MColumnName2 = "Smith" });  
      MColumnsList.Add(new MandatoryColumns() { MColumnName = "Jason", MColumnName2 = "Bell" });  
      MColumnsList.Add(new MandatoryColumns() { MColumnName = "Jason1", MColumnName2 = "Bell2" });  
       
    }  
    public event PropertyChangedEventHandler PropertyChanged;  
    protected void OnPropertyChanged([CallerMemberName] string name = null)  
    {  
      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));  
    }  
  }  
  public class MandatoryColumns  
  {  
    public string MColumnName { get; set; }  
    public string MColumnName2 { get; set; }  
  
    public override string ToString()  
    {  
      return (MColumnName + "--"+MColumnName2) .ToString();  
    }  
  }  
}

Update:
MainWindow.xaml:

MainWindow.xaml.cs:

public class ViewModel : INotifyPropertyChanged  
  {  
    private CollectionViewSource cvs = new CollectionViewSource();  
    public ICollectionView View  
    {  
      get  
      {  
        cvs.Source = InitImput();  
        return cvs.View;  
      }  
    }  
    public ViewModel()  
    {  
      CmdSaveNew = new RelayCommand(SaveNew);  
      CmdDelete = new RelayCommand(DeleteItem);  
    }  
     int id=5;  
    public void SaveNew(object parameter)  
    {  
      if (!string.IsNullOrEmpty("x"))   
      {  
        Model cat = new Model();  
        cat.Cont1 = $"{id}";   
        cat.Cont2 = "";   
        cat.Cont3 = "";   
          Input.Add(cat);  
        MessageBox.Show("success");  
        id+=1;  
      }  
      else  
      {  
        MessageBox.Show("error");  
      }  
    }  
    public void DeleteItem(object parameter)  
    {  
      if (SelectedItem != null)  
      {  
        Input.Remove(SelectedItem);  
      }  
    }  
    public ICommand Cmd { get => new RelayCommand(CmdExec); }  
    public ICommand CmdSaveNew { get; set; }  
    public ICommand CmdDelete { get; set; }  
  
    private void CmdExec(object parameter)  
    {  
      switch (parameter.ToString())  
      {  
        case "Iterate":  
  
          for (int i = 0; i < Input.Count; i++)  
          {  
            Output.Add(Input[i]);  
          }  
  
          MessageBox.Show("Items Added");  
          break;  
  
        default:  
          break;  
      }  
    }  
    private Model _selectedItem;  
    public Model SelectedItem  
    {  
      get { return _selectedItem; }  
      set  
      {  
        _selectedItem = value;  
        OnPropertyChanged("SelectedItem");  
      }  
    }  
    private ObservableCollection output = new ObservableCollection();  
    public ObservableCollection Output { get { return output;}set{ output=value;OnPropertyChanged("Output");} }   
  
  
    public event PropertyChangedEventHandler PropertyChanged;  
    protected void OnPropertyChanged([CallerMemberName] string name = null)  
    {  
      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));  
    }  
  
    ObservableCollection Input = new ObservableCollection();  
    public ObservableCollection InitImput()  
    {  
      Input.Add(new Model() { Cont1 = "1", Cont2 = "A", Cont3 = "a" });  
      Input.Add(new Model() { Cont1 = "2", Cont2 = "B", Cont3 = "b" });  
      Input.Add(new Model() { Cont1 = "3", Cont2 = "C", Cont3 = "c" });  
      Input.Add(new Model() { Cont1 = "4", Cont2 = "D", Cont3 = "d" });  
  
      return Input;  
    }  
  
  }  
  
  public class Model  
  {  
    public string Cont1 { get; set; }  
    public string Cont2 { get; set; }  
    public string Cont3 { get; set; }  
    public override string ToString()  
    {  
      return Cont1+ Cont2+ Cont3 .ToString();  
    }  
  }  
  
  public class RelayCommand : ICommand  
  {  
    private readonly Predicate

Answer

Hi Sarah,
the simplest way is to use Input for Add to Output because Input is binded to ListView and reflect all Items in LIstView:

public ICommand Cmd { get => new RelayCommand(CmdExec); }
private void CmdExec(object parameter)
{
  switch (parameter.ToString())
  {
    case "Iterate":
      for (int i = 0; i < Input.Count; i++) Output.Add(Input[i]);
      MessageBox.Show("Items Added");
      break;
    default:
      break;
  }
}

How to Iterate listview items using MVMV

2 answers