System.Windows.DependencyObject.GetHashCode C# (CSharp) Method

        public override sealed int GetHashCode()
        {
            throw new NotImplementedException("GetHashCode");
        }

        /// <summary>
        /// Searchs an element in the visual tree matching with the given hash code. 
        /// </summary>
        /// <param name="obj">A element in the visual tree as root element to search downwards the tree.</param>
        /// <param name="hashCode">The hash code to search for.</param>
        /// <returns>The element in the visual three matching the given hash code, otherwise null</returns>
        /// <remarks>
        /// This method is especially used in case where the visual tree is not part of the 
        /// main visual tree of the Silverlight application, as it happen with popup controls.
        /// Optain the hash code from the output of WriteDownwards/WriteUpwards.
        /// </remarks>
        public static DependencyObject GetElementByHashCode(DependencyObject obj, int hashCode)
        {
            if (obj == null)
                return null;

            // check if hash code matches
            if (obj.GetHashCode() == hashCode)
                return obj;

            // store child count local
            int childCount = VisualTreeHelper.GetChildrenCount(obj);

            // check if one of the child match to the hash code
            for (int i = 0; i < childCount; i++)
            {
                DependencyObject child = VisualTreeHelper.GetChild(obj, i);
                if (child.GetHashCode() == hashCode)
                    return child;
            }

            // go down the tree
            for (int i = 0; i < childCount; i++)
            {
                DependencyObject child = VisualTreeHelper.GetChild(obj, i);
                DependencyObject returnObj = GetElementByHashCode(child, hashCode);

                // if object was found, return
                if (returnObj != null)
                    return returnObj;
            }

            // nothing found
            return null;
        }