class Model
{
  public string A {get; set;}
  public string B {get; set;}

  public override ToString() { return A + "," + B; }
}

class ViewModel : ViewModelBase // INotifyPropertyChanged -- SetField() mainly	 
{
  public ViewModel()
  {
    Models = new ObservableCollection<Model>();
    Models.Add(new Model { A = "123", B = "abc" });
    Models.Add(new Model { A = "456", B = "def" });
  }

  public ObservableCollection<Model> Models {get; set;}
  Model _SelectedModel;
  public Model SelectedModel
  {
    get { return _SelectedModel; }
    set { SetField(ref _SelectedModel, value); IsModelSelected = value != null; }
  }

  bool _IsModelSelected;
  public bool IsModelSelected
  {
    get { return _IsModelSelected; }
    set { SetField(ref _IsModelSelected, value); }
  }

  public RelayCommand AddCommand
  {
    get
    {
      return new RelayCommand(x =>
      {
        Model m = new Model();
        Models.Add(m);
        SelectedModel = m;
      });
    }
  }
}

<Window ...>
  <StackPanel>
    <Button Content="Add New" Command="{Binding AddCommand}" />
    <ListBox Height="100" ItemsSource="{Binding Models}" SelectedItem="{Binding SelectedModel}">
      <ListBox.ItemTemplate>
        <DataTemplate>
          <TextBlock>
            <TextBlock.Text>
             <MultiBinding StringFormat="{}{0},{1}">
               <Binding Path="A" />
               <Binding Path="B" />
             </MultiBinding>
            </TextBlock.Text>
          </TextBlock>
        </DataTemplate>
      </ListBox.ItemTemplate>
    </ListBox>
    <TextBox Text="{Binding SelectedModel.A, UpdateSourceTrigger=PropertyChanged}" IsEnabled="{Binding IsModelSelected}" />
    <TextBox Text="{Binding SelectedModel.B, UpdateSourceTrigger=PropertyChanged}" IsEnabled="{Binding IsModelSelected}" />
  </StackPanel>
</Window>

Ciaphas fucked around with this message at 01:04 on Aug 6, 2015

raminasi fucked around with this message at 21:15 on Aug 5, 2015

class Model
    {
      public string A {get; set;}
      public string B {get; set;}
    }

    public class ViewModel
    {
        public Model Model {get;set;}
        public string A 
        {
            get{return Model.A;}
            set{Model.A = value;
                INotifyPropertyChanged();
            }
        }
        public string B 
        {
            get{return Model.B;}
            set{Model.B = value;
                INotifyPropertyChanged();
            }
        }

        public string Concated
        {
            get{return String.Format("{0},{1}",Model.A,Model.B);}
        }
        public ViewModel(Model model)
        {
            Model = model;
        }
    }

C# code:

    class ViewModels : ViewModelBase // INotifyPropertyChanged -- SetField() mainly	 
    {
      public ViewModels()
      {
        ViewModels = new ObservableCollection<ViewModel>();
        ViewModels.Add(new ViewModel(new Model { A = "123", B = "abc" }));
        ViewModels.Add(new ViewModel(new Model { A = "456", B = "def" }));
      }
    
      public ObservableCollection<Model> ViewModels {get; set;}
      ViewModel _selectedViewModel;
      public ViewModel SelectedViewModel
      {
        get { return _selectedViewModel; }
        set { _selectedViewModel = value;
              NotifyPropertyChanged();
            }
      }
    
      public bool IsViewModelSelected()
      {
          if(_selectedViewModel != null)
          {
              return true;
          }
          return false;
      }


    
      public RelayCommand AddCommand
      {
        get
        {
          return new RelayCommand(x =>
          {
            Model m = new Model();
            Models.Add(m);
            SelectedViewModel = m;
          });
        }
      }
    }


<Window ...>
  <StackPanel>
    <Button Content="Add New" Command="{Binding AddCommand}" />
    <ListBox Height="100" ItemsSource="{Binding ViewModels}" SelectedItem="{Binding SelectedViewModel}">
      <ListBox.ItemTemplate>
        <DataTemplate>
          <TextBlock Text="{Binding Concated}"/>
        </DataTemplate>
      </ListBox.ItemTemplate>
    </ListBox>
    <TextBox Text="{Binding SelectedViewModel.A}" IsEnabled="{Binding IsViewModelSelected}" />
    <TextBox Text="{Binding SelectedViewModel.B}" IsEnabled="{Binding IsViewModelSelected}" />
    <Label Content="{Binding SelectedViewModel}"/>
  </StackPanel>
</Window>

Mr Shiny Pants fucked around with this message at 21:50 on Aug 5, 2015

• What would I change to make this program work exactly the same way, without binding directly to the selected model object's properties from the view (i.e. if I was not allowed to bind to SelectedModel.A or SelectedModel.B from the view)? In other words, how would I remove all knowledge of the Model's exact contents from the View? (I'm aware that I'd still, effectively, have to edit an A and B property in the ViewModel, but that's still not the same as directly editing the Model. I just don't know how to do up these proxy properties such that everything else appears to be updated automatically.)
  
• Would I even ever want to do this from an MVVM purist point of view or am I totally up the wrong tree? (Normally I don't give a poo poo about being completely purist about anything, but I need to know the rules before I can confidently break them.)
  

Ciaphas fucked around with this message at 01:21 on Aug 6, 2015

putin is a cunt fucked around with this message at 01:15 on Aug 6, 2015

hoursNumericUpDown.DataBindings.Add(New Binding("Value", Me, "HoursWorked"))

chippy fucked around with this message at 17:53 on Aug 6, 2015

public readonly property HoursWorked as integer
if hoursNumericUpDown is nothing then return 0 else return hoursNumericUpDown.Value
end property

NihilCredo fucked around with this message at 19:41 on Aug 6, 2015

Bognar fucked around with this message at 20:49 on Aug 6, 2015

<!-- datacontext is my VM-->
<!--works the same with default UpdateSourceTrigger, just easier to see-->
<TextBox Text="{Binding MyValue.Value, UpdateSourceTrigger=PropertyChanged}"/>
<TextBlock Text="{Binding MyValue.Value}"/>

class VM
{
  public VM() { MyValue = new MyValueClass(); }
  public MyValueClass MyValue {get; set;}
}
class MyValueClass
{
  public string Value {get; set;}
}

Ciaphas fucked around with this message at 23:38 on Aug 6, 2015

class VM : ObservableBase // INPC
{
  string _A;
  public string A
  {
    get { return _A; }
    set { SetField(ref _A, value); }
  }

  string _B;
  public string B
  {
    get { return _B; }
    set { SetField(ref _B, value); }
  }

  [INPCDepends("A", "B")] // nameof A, nameof B in C# 6 :(
  public string Combo
  {
    get { return A + "," + B; }
  }
}

Ciaphas fucked around with this message at 23:07 on Aug 7, 2015