Xamarin Forms - GetBindingExpression

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In Silverlight (and other XAML based technologies) there is a method called GetBindingExpression which allows us to check what binding there is on a given dependency property. The method is on FrameworkElement so every single control gives us access to the binding expression.

For example:

var selectedItemBindingExpression = GetBindingExpression(SelectedItemProperty);

But, there doesn't seem to be an equivalent in Xamarin Forms. Is there a way to get a binding expression from a BindableProperty property in Xamarin Forms?

xamarin.forms silverlight wpf c#
2 Answers

Improved Sharada Gururaj's solution:

public static class BindingObjectExtensions
{
    private static MethodInfo _bindablePropertyGetContextMethodInfo = typeof(BindableObject).GetMethod("GetContext", BindingFlags.NonPublic | BindingFlags.Instance);
    private static FieldInfo _bindablePropertyContextBindingFieldInfo;

    public static Binding GetBinding(this BindableObject bindableObject, BindableProperty bindableProperty)
    {
        object bindablePropertyContext = _bindablePropertyGetContextMethodInfo.Invoke(bindableObject, new[] { bindableProperty });

        if (bindablePropertyContext != null)
        {
            FieldInfo propertyInfo = _bindablePropertyContextBindingFieldInfo = 
                _bindablePropertyContextBindingFieldInfo ?? 
                    bindablePropertyContext.GetType().GetField("Binding");

            return (Binding) propertyInfo.GetValue(bindablePropertyContext);
        }

        return null; 
}

My solution has following improvements:

  1. Caching of objects obtained by reflection (improves performance)
  2. Removed unnecessary null checks
  3. Use of reflection directly, the use of IntrospectionExtensions is unnecessary
  4. GetBindingExpression method is not needed (all information about the binding can be retrieved from the Binding class)
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