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

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

Answer 1

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));