XamlParseException Failed to assign to property. Binding not working with attached property - xaml

Question

I want to create custom text box with attached property for Windows Store app. I am following this solution. Now it uses hard coded value as property value but I want to set value using binding, but it's not working. I tried to search a lot but didn't helped me any solution.
The exception details is like this
An exception of type 'Windows.UI.Xaml.Markup.XamlParseException'
occurred in CustomTextBox.exe but was not handled in user code
WinRT information: Failed to assign to property
'CustomTextBox.Input.Type'.
MainPage.xaml
<!-- local:Input.Type="Email" works -->
<!-- local:Input.Type="{Binding SelectedTextboxInputType}" not working -->
<TextBox x:Name="txt" local:Input.Type="{Binding SelectedTextboxInputType}" Height="30" Width="1000" />
<ComboBox x:Name="cmb" ItemsSource="{Binding TextboxInputTypeList}" SelectedItem="{Binding SelectedTextboxInputType}" Height="30" Width="200"
Margin="451,211,715,527" />
MainPage.xaml.cs
public sealed partial class MainPage : Page
{
public MainPage()
{
this.InitializeComponent();
DataContext = new ViewModel();
}
}
Input.cs
//InputType is enum
public static InputType GetType(DependencyObject obj)
{
return (InputType)obj.GetValue(TypeProperty);
}
public static void SetType(DependencyObject obj, InputType value)
{
obj.SetValue(TypeProperty, value);
}
public static readonly DependencyProperty TypeProperty =
DependencyProperty.RegisterAttached("Type", typeof(InputType), typeof(TextBox), new PropertyMetadata(default(InputType), OnTypeChanged));
private static void OnTypeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue is InputType)
{
var textBox = (TextBox)d;
var Type = (InputType)e.NewValue;
if (Type == InputType.Email || Type == InputType.URL)
{
textBox.LostFocus += OnLostFocus;
}
else
{
textBox.TextChanged += OnTextChanged;
}
}
}
ViewModel.cs
public class ViewModel : BindableBase
{
public ViewModel()
{
TextboxInputTypeList = Enum.GetValues(typeof(InputType)).Cast<InputType>();
}
private InputType _SelectedTextboxInputType = InputType.Currency;
public InputType SelectedTextboxInputType
{
get { return _SelectedTextboxInputType; }
set { this.SetProperty(ref this._SelectedTextboxInputType, value); }
}
private IEnumerable<InputType> _TextboxInputTypeList;
public IEnumerable<InputType> TextboxInputTypeList
{
get { return _TextboxInputTypeList; }
set { this.SetProperty(ref this._TextboxInputTypeList, value); }
}
}

Answer 1

This is a pretty common mistake. The problem is, binding targets cannot be CLR properties in XAML. It's just the rules. A binding source can be a CLR property, just fine. The targets simply must be dependency properties.
We all get the error! :)
I describe the whole thing here: http://blogs.msdn.com/b/jerrynixon/archive/2013/07/02/walkthrough-two-way-binding-inside-a-xaml-user-control.aspx
Best of luck.

Answer 2

Incorrect
public static readonly DependencyProperty TypeProperty =
DependencyProperty.RegisterAttached("Type", typeof(InputType), typeof(TextBox), new PropertyMetadata(default(InputType), OnTypeChanged));
Correct
public static readonly DependencyProperty TypeProperty =
DependencyProperty.RegisterAttached("Type", typeof(InputType), typeof(Input), new PropertyMetadata(default(InputType), OnTypeChanged));