BindingEx

using System;
using System.Reflection;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Data;
using System.Windows.Markup;
using System.Windows;
using Kvint.Irradiant.Core;
using System.Windows.Threading;
using System.Collections.ObjectModel;
using System.Windows.Controls;

namespace Kvint.Irradiant.WPFHelpers
{
    /// <summary>
    /// Класс DataBinding'а перебасывающего исключения.
    /// </summary>
    public class BindingEx : Binding
    {
        #region Private members

        private static readonly UpdateSourceExceptionFilterCallback m_ExceptionHandler = ExceptionHandler;
        private static readonly Action<BindingExpressionBase, Exception> m_RethrowHelper = RethrowHelper;
        private static readonly Func<BindingExpressionBase, DependencyObject> m_TargetAccessor;

        private static void RethrowHelper(BindingExpressionBase bex, Exception exception)
        {
            bex.UpdateTarget();

            // "Тихие" исключения надо просто глотать, они произошли в другом стеке,
            // перебрасывать их просто совершенно бессмысленно.

            if (exception is CancelException) return;
            throw NotifyUserException.Wrap(exception);
        }

        private static object ExceptionHandler(object bindingExpression, Exception exception)
        {
            var bex = bindingExpression as BindingExpression;
            if (null == bex) return null;
            var dobj = m_TargetAccessor(bex);
            dobj.Dispatcher.BeginInvoke(m_RethrowHelper, bex, exception);
            return null;
        }

        private void InitExceptionHandling()
        {
            UpdateSourceExceptionFilter = m_ExceptionHandler;
            ValidatesOnExceptions = true;
        }

        static BindingEx()
        {
            var propInfo = typeof(BindingExpressionBase).GetProperty(
                "TargetElement", BindingFlags.Instance | BindingFlags.NonPublic);
            var accessors = propInfo.GetAccessors(true);
            m_TargetAccessor = (Func<BindingExpressionBase, DependencyObject>)
                Delegate.CreateDelegate(
                    typeof(Func<BindingExpressionBase, DependencyObject>), accessors[0]);
        }

        #endregion

        #region Public members

        /// <summary>
        /// Конструктор.
        /// </summary>
        public BindingEx()
        {
            InitExceptionHandling();
        }

        /// <summary>
        /// Конструктор.
        /// </summary>
        /// <param name="path">Путь к свойству.</param>
        public BindingEx(string path) : base (path)
        {
            InitExceptionHandling();
        }

        #endregion
    }

    /// <summary>
    /// Класс DataBinding'а перебасывающего исключения для стилей.
    /// </summary>
    public sealed class BindingExS : MarkupExtension
    {
        #region Private members

        private BindingEx m_Binding;

        #endregion

        #region Public members

        /// <summary>
        /// Конструктор.
        /// </summary>
        public BindingExS()
        {
            m_Binding = new BindingEx();
        }

        /// <summary>
        /// Конструктор.
        /// </summary>
        /// <param name="path">Путь к свойству.</param>
        public BindingExS(string path)
        {
            m_Binding = new BindingEx(path);
        }

        /// <summary>
        /// Gets or sets the path.
        /// </summary>
        /// <value>The path.</value>
        public PropertyPath Path
        {
            get { return m_Binding.Path; }
            set { m_Binding.Path = value; }
        }

        /// <summary>
        /// Gets or sets the mode.
        /// </summary>
        /// <value>The mode.</value>
        public BindingMode Mode
        {
            get { return m_Binding.Mode; }
            set { m_Binding.Mode = value; }
        }

        /// <summary>
        /// Gets or sets the update source trigger.
        /// </summary>
        /// <value>The update source trigger.</value>
        public UpdateSourceTrigger UpdateSourceTrigger
        {
            get { return m_Binding.UpdateSourceTrigger; }
            set { m_Binding.UpdateSourceTrigger = value; }
        }

        /// <summary>
        /// Gets the validation rules.
        /// </summary>
        /// <value>The validation rules.</value>
        public Collection<ValidationRule> ValidationRules
        {
            get { return m_Binding.ValidationRules; }
        }

        /// <summary>
        /// When implemented in a derived class, returns an object that is set as the value of the target property for this markup extension.
        /// </summary>
        /// <param name="serviceProvider">Object that can provide services for the markup extension.</param>
        /// <returns>
        /// The object value to set on the property where the extension is applied.
        /// </returns>
        public sealed override object ProvideValue(IServiceProvider serviceProvider)
        {
            return m_Binding;
        }

        #endregion
    }
}