CODEWITHSUNDEEP
c#wpfxaml
Dalbuho
Dalbuho

Reputation: 13

How do I Data Bind between a TextBox and a Label in two different windows?

I have created a program that changes the text in a Label on the first window when you type in a TextBox on the second window. The idea is that I want to open a new window from my first window then on this new I want to type in a name and press a button to have that name be displayed on the first window. Am I making myself understood? Can anyone help me out? Thanks in advance!

The First Window(MainWindow)--

    public partial class MainWindow : Window
{

    public MainWindow()
    {
        InitializeComponent();
    }

    private void button_Click(object sender, RoutedEventArgs e)
    {
        var createPlayerWindow = new CreatePlayerWindow();
        DataContext = this;
        createPlayerWindow.Show();
    }
}

Xaml for MainWindow--

    <Grid>
    <Label x:Name="label2" Content="Name:" HorizontalAlignment="Left" Margin="10,63,0,0" VerticalAlignment="Top"/>
    <Label x:Name="lblName" Content="{Binding Path=Name, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" Margin="90,63,0,0" VerticalAlignment="Top"/>
    <Button x:Name="button" Content="Create Player" HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top" Width="81" Click="button_Click"/>

</Grid>

The Second Window(CreatePlayerWindow)--

    public partial class CreatePlayerWindow : Window
{
    public CreatePlayerWindow()
    {
        InitializeComponent();
    }

    private void button_Click(object sender, RoutedEventArgs e)
    {
        string playerName = txbName.Text;

        Player player = new Player(playerName);
        this.DataContext = player;
    }
}

Xaml for CreatePlayerWindow--

    <Grid>
    <Label x:Name="label" Content="Name :" HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top"/>
    <TextBox x:Name="txbName" HorizontalAlignment="Left" Height="23" Margin="63,12,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
    <Button x:Name="button" Content="Create Player" HorizontalAlignment="Left" Margin="101,129,0,0" VerticalAlignment="Top" Width="88" Click="button_Click"/>
    <Label x:Name="label1" Content="Class :" HorizontalAlignment="Left" Margin="10,41,0,0" VerticalAlignment="Top"/>
    <ComboBox x:Name="cmbClass" HorizontalAlignment="Left" Margin="63,45,0,0" VerticalAlignment="Top" Width="120"/>

</Grid>

The Model(Player)--

    public class Player : ViewModelBase
{
    private string _name;

    public string Name
    {
        get
        {
            return this._name;
        }
        set
        {
            this._name = value;
            OnPropertyChanged();
        }
    }

    public Player(string name)
    {
        _name = name;
    }
}

The ViewModel(ViewModelBase)--

    public class ViewModelBase : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged([CallerMemberName]string name = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
    }
}

Upvotes: 1

Views: 552

Answers (2)

ΩmegaMan
ΩmegaMan

Reputation: 31606

Have the main page's data context and the window's data context use the same instantiated VM which will have a Name property they both will use.

Then in xamls bind appropriately to the Name property on the VM which will adhere to the INotifyPropertyChange notification so that when it changes it will update the other item.

Don't forget that on the editing XAML the binding Mode should be TwoWay otherwise the user changes will not be seen.

Upvotes: 1

Michael W&#252;rthner
Michael W&#252;rthner

Reputation: 353

Your MainWindow needs a ViewModel for its databinding. DataContext = this is useless here. So create a new class with a PlayerName property (with backing field), instanciate it in MainWindow constructor and set the main windows databinding to it. In the setter call OnPropertyChanged after setting the backingfield to value. Bind your label to the PlayerName property.

In your click event, you should create a viewmodel(player-)instance of your createplayerwindow and bind it to the createplayerwindow-instance's datacontext. add the missing databindings in your createplayerwindow to update your viewmodel (twoway). Replace the Show() method invocation in your button click event with ShowDialog(). After ShowDialog invokation call the new properties setter with the viewmodel.name value.

Upvotes: 1

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