WPF Radio button does not update after several binding

Question

I have an application that allows users to move forward and backward
And the radio button is implemented like following:

For the first 4 times, I change the selected item for the radio button and then move next and then come back and do the same, the radio buttons work fine and the model is updated correctly as its GUI. However, after the first 4 times moving forwards and backwards, the radio buttons do not update its GUI.

Following is the navigation system:

Model and view are bound based on Next/Back button

Check boxs works fine! Please give me some suggestions.
Thanks in advance

Answer 1

I finally found the answer:

If you have tried to bind the RadioButton’s IsChecked property in WPF to an object, you have most likely experienced the following problem: In OneWay bindings it works great. But if you have more than one RadioButtons binded TwoWay and you click on an unchecked one, you were expecting that the object to which the previously checked RadioButton was binded to receive the value of False. But you were wrong in your expectations. That’s because for some reasons Microsoft does not obey bindings and does not pass the False value to the DependencyProperty and instead of that they just assign the value False directly to the property, which ruins the binding.

There are many proposed solutions to this around the internet, problem with all those is that they do not work with dynamically generated controls. So since I had to find a way to make this working with dynamic controls, decided to make a wrapper of the real RadioButton which will correctly Bind in two ways. Here is the code for the wrapper:

using System;
using System.IO;
using System.Printing;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Interop;
using System.Windows.Media;
using Microsoft.Win32;

namespace Controls
{
    public class RadioButtonExtended : RadioButton
    {
        static bool m_bIsChanging = false;

        public RadioButtonExtended()
        {
            this.Checked += new RoutedEventHandler(RadioButtonExtended_Checked);
            this.Unchecked += new RoutedEventHandler(RadioButtonExtended_Unchecked);
        }

        void RadioButtonExtended_Unchecked(object sender, RoutedEventArgs e)
        {
            if (!m_bIsChanging)
                this.IsCheckedReal = false;
        }

        void RadioButtonExtended_Checked(object sender, RoutedEventArgs e)
        {
            if (!m_bIsChanging)
                this.IsCheckedReal = true;
        }

        public bool? IsCheckedReal
        {
            get { return (bool?)GetValue(IsCheckedRealProperty); }
            set
            {
                SetValue(IsCheckedRealProperty, value);
            }
        }

        // Using a DependencyProperty as the backing store for IsCheckedReal. This enables animation, styling, binding, etc...
        public static readonly DependencyProperty IsCheckedRealProperty =
        DependencyProperty.Register("IsCheckedReal", typeof(bool?), typeof(RadioButtonExtended),
        new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.Journal |
        FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
        IsCheckedRealChanged));

        public static void IsCheckedRealChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            m_bIsChanging = true;
            ((RadioButtonExtended)d).IsChecked = (bool)e.NewValue;
            m_bIsChanging = false;
        }
    }
}

So now all you have to do is to use the ExtendedRadioButton instead of the built-in one and bind to the IsCheckedReal property instead of the IsChecked one. Enjoy 🙂