Simple Binding of Data from code behind to XAML

Question

I am new to WPF concepts. I want to just display a string in a textbox. I tried the following C# code and XAML to bind a string to a TextBox.Text property. C# code:

Answer 1

Databinding does not work with fields. Use Properties instead:

public int TmpVal {get; set;}
public string TmpStr {get; set;}

Also if you want the textbox to automatically pick up changes from your data you would ideally need to implement INotifyPropertyChanged or make it a dependency property or have a XXXChanged event for each XXX property (this doesn't work anymore).

<Window x:Class="WpfApplication5.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300" x:Name="ThisWindow">
    <StackPanel>
        <TextBox Name="txtTest1" Text="{Binding TmpStr, ElementName=ThisWindow}" />
        <Button Name="butTest1"  Click="viewButton_Click">Test123</Button>
    </StackPanel>
</Window>

And the code behind:

public partial class Window1 : Window, INotifyPropertyChanged
{
    public Window1()
    {
        this.TmpStr = "Windows Created";
        this.InitializeComponent();
        this.DataContext = this;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    public string TmpStr { get; set; }

    public int TmpVal { get; set; }

    private void viewButton_Click(object sender, RoutedEventArgs args)
    {
        this.TmpStr = "Button clicked";
        if (this.PropertyChanged != null)
        {
            this.PropertyChanged(this, new PropertyChangedEventArgs("TmpStr"));
        }
    }
}