How do I bind a Listview SelectedItem to a Textbox using the TwoWay mode?

Question

I am very new to WPF and testing some things that I would like to include in an application that I will be working on. I have a 2 row ListView (bound to a textbox) with the names Scott Guthrie and Jon Skeet in it. I am trying to select "Scott Guthrie" in the ListView and have it populate the TextBox. I want to be able to edit the text and tab off and have the ListView updated.

Edit:I removed the code since that really didn't add anything to the question.

Answer 1

Wow, that's really complicated what you've got there.

This can be accomplished in a very simple way. You need a model to represent the programmer, a view model to hold a list of programmers, and simple binding to take care of the rest.

The model:

public sealed class Programmer
{
    public string Name { get; set; }
}

Its very simple. An object representing a programmer with a name. We must encapsulate the name within an object because strings are immutable in .NET. If you tried binding against a single string in a list of strings, changes wouldn't propagate.

The collection of programmers is kept in a ViewModel. In this case, I call it ViewModel, because I have no imagination. This view model contains everything that the view binds against. In this case, its the list of programmers.

public sealed class ViewModel
{
    public ObservableCollection<Programmer> Programmers { get; private set; }

    public ViewModel()
    {
        Programmers = new ObservableCollection<Programmer>();
    }
}

The ViewModel is set as the DataContext of our view. The DataContext flows down the visual tree, and we can bind against it at any point.

public MainWindow()
{
    var vm = new ViewModel();
    vm.Programmers.Add(new Programmer { Name = "Jon Skeet" });
    vm.Programmers.Add(new Programmer { Name = "Scott Guthrie" });
    DataContext = vm;
    InitializeComponent();
}

You can set the DataContext in any way you want; I'm doing it here for simplicity's sake.

In the UI, I simply bind the ListView against the list of Programmers in the ViewModel (the DataContext, unless otherwise stated, is the root of the binding path). I then bind the TextBox against the SelectedItem of the ListBox. You select a Programmer from the list, which then becomes the SelectedItem, which I can then change the Name of.

<Window
    x:Class="Programmers.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:t="clr-namespace:Programmers"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition />
            <ColumnDefinition />
        </Grid.ColumnDefinitions>
        <ListBox
            x:Name="list"
            ItemsSource="{Binding Programmers}"
            DisplayMemberPath="Name" />
        <TextBox
            Grid.Column="1"
            VerticalAlignment="Top"
            Text="{Binding SelectedItem.Name, ElementName=list}" />
    </Grid>
</Window>

Simple, once you get the hang of it.

Answer 2

This works (except that you need to validate the textbox since you can enter any text.. a dropdown might be a better choice).

View:

<TabItem x:Name="RightTabPage" Header="RightModel"  DataContext="{Binding Right}">
                    <StackPanel>
                        <TextBox Text="{Binding SelectedGuru}"/>
                        <ListView SelectedItem="{Binding SelectedGuru}" ItemsSource="{Binding Gurus}"/>
                    </StackPanel>
                </TabItem>

ViewModel:

public class RightViewModel
    {
        public RightViewModel()
        {
            Gurus = new[] {"Scott Guthrie", "Jon Skeet"};
            SelectedGuru = Gurus.First();
        }

        public string SelectedGuru { get; set; }
        public IEnumerable<string> Gurus{ get; set; }
    }