WPF Databinding TextBox to integer property in another object

Although this question is old, it's a good one, and is rarely answered succinctly. Let me offer a simplified solution for others who come upon this page.

In order to support two-way binding, your initial ConfigurationData class must be expanded to support property changes. Otherwise the changes in DoStuff() will not be reflected in the UI textbox. Here is a typical way of doing that:

using System.ComponentModel;
public class ConfigurationData : INotifyPropertyChanged
{
    private int _BaudRate;
    public int BaudRate
    {
        get { return _BaudRate; }
        set { _BaudRate = value; OnPropertyChanged("BaudRate"); }
    }

    //below is the boilerplate code supporting PropertyChanged events:
    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged(string name)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(name));
        }
    }
}

I choose to put the textbox binding right in the XAML (I've also added a button to DoStuff), like so:

<Canvas>
    <TextBox Width="96" Name="textBox1" Text="{Binding BaudRate}" />
    <Button  Width="96" Canvas.Top="25" Content="ChangeNumber" Click="DoStuff"/>
</Canvas>

The tricky part is gluing this all together. For that you'll need to define your DataContext. I prefer to do this in the constructor of my main window. Here's the code:

public partial class MainWindow : Window
{
    private ConfigurationData m_data;
    public MainWindow()
    {
        InitializeComponent();
        m_data = new ConfigurationData();
        this.DataContext = m_data;  // This is the glue that connects the
                                    // textbox to the object instance
    }

    private void DoStuff(object sender, RoutedEventArgs e)
    {
        m_data.BaudRate += 300;
    }
}

I'm sure there's a better way (please tell me!), but here's one way I cobbled together that works. It seems that there should be an easier way. For the property BaudRate use:

public int BaudRate
    {
        get
        { 
            return m_baudRate;
        }
        set 
        {
            if (value != m_baudRate)
            {
                m_baudRate = value;
                OnPropertyChanged("BaudRate");//OnPropertyChanged definition left out here, but it's pretty standard
            }
        }
    }

For the XAML, I have no significant markup:

<TextBox  Height="23" Margin="137,70,21,0" Name="textBox1" VerticalAlignment="Top"  />

Now this is the messy part... Create class for validation:

public class IntRangeRule : ValidationRule
{
    // See ValidationRule Class
    public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
    {
        try
        {
            if (value is int) // replace with your own logic or more robust handling...
            {
                return new ValidationResult(true, "Fine");
            }
            else
            {
                return new ValidationResult(false, "Illegal characters or ");
            }
        }

        catch (Exception e)
        {
            return new ValidationResult(false, "Illegal characters or " + e.Message);
        }


    }
}

And then in the constructor of Window1 (MainWindow), have:

Binding myBinding = new Binding("BaudRate");
        myBinding.NotifyOnValidationError = true;
        myBinding.Mode = BindingMode.TwoWay;
        ValidationRule rule = new IntRangeRule();
                    myBinding.ValidationRules.Add(rule);
        myBinding.Source = m_data; // where m_data is the member variable of type ConfigurationData
        textBox1.SetBinding(TextBox.TextProperty, myBinding);

All my attempts to do everything in markup failed. Better ways?

Dave