Question

I am creating an application that uses several threads as a result I want to try to use UIControls in my code behind as few as possible. The way I do it is by binding the controls to a property in my code behind that way I will be able to update the control by changing that property it does not matter if that property is updated on a different thread. Anyways I am creating the following code in order for the class to create the bindings form me.

public static class MyExtensionMethods 
{

    public static TextBoxBind<T> BindTextBox<T>(this TextBox textbox, string property=null)
    {
        return new TextBoxBind<T>(textbox,property);
    }
}



public class TextBoxBind<T> : INotifyPropertyChanged
{
    string property;

    protected T _Value;
    public T Value
    {
        get { return _Value; }
        set { _Value = value; OnPropertyChanged(property); }
    }

    public event PropertyChangedEventHandler PropertyChanged = delegate { };
    protected void OnPropertyChanged(string propertyName){
        PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }

    public TextBoxBind(TextBox textbox, string property)
    {
        if (property == null)
        {
            property = "Value";
        }
        this.property = property;

        Binding b = new Binding(property)
       {
            Source = this
       };

        b.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
        textbox.SetBinding(TextBox.TextProperty, b);
    }
}

And on my XAML I have:

 <TextBox  Name="textBox2"  />

Therefore I will be able to use the first code that I posted as:

        var newTextBox2 = textBox2.BindTextBox<int>();
        newTextBox2.Value = 50; // this will update the textBox2.Text = "2"
        // also every time I update the value of textBox2  newTextBox2.Value will update as well

The problem is when I try to bind it to a custom object. Take this code for example:

    public class Person 
    {
        public string Name { get; set; }
        public string Age { get; set; }

        public override string ToString()
        {
            return Age.ToString();
        }            

    }

    void LogIn_Loaded(object sender, RoutedEventArgs e)
    {
        txtUsuario.Focus();

        var newTextBox2 = textBox2.BindTextBox<Person>("Age");

        // here newTextBox2 never updates....


    }

Answer 1

OnPropertyChanged(property); should be pointing to Value, since that’s the Name of your Property.
This should not be pointing to the type T.
So this code is not right:

if (property == null) 
{ 
  property = "Value"; 
}

because property should always be "Value"

public T Value     
{     
    get { return _Value; }     
    set { _Value = value; OnPropertyChanged("Value"); }     
}