得到子指定元素方法和得到指定子元素集合方法mvvm得到焦点

public class UIHelper

{

    /// <summary>

    /// 在Visual里找到想要的元素

    /// childName可为空，不为空就按名字找

    /// </summary>

    public static T FindChild<T>(DependencyObject parent, string childName)

       where T : DependencyObject

    {

        if (parent == null)return null;

 

        T foundChild = null;

 

        int childrenCount = VisualTreeHelper.GetChildrenCount(parent);

        for (int i = 0; i < childrenCount; i++)

        {

            var child = VisualTreeHelper.GetChild(parent, i);

 

            T childType = child as T;

            if (childType == null)

            {

                // 住下查要找的元素

                foundChild = FindChild<T>(child, childName);

 

                // 如果找不到就反回

                if (foundChild != null)break;

            }

            else if (!string.IsNullOrEmpty(childName))

            {

                var frameworkElement = child as FrameworkElement;

                // 看名字是不是一样

                if (frameworkElement != null && frameworkElement.Name == childName)

                {

                    //如果名字一样返回

                    foundChild = (T)child;

                    break;

                }

            }

            else

            {

                // 找到相应的元素了就返回

                foundChild = (T)child;

                break;

            }

        }

 

        return foundChild;

    }

 

    /// <summary>

    /// 得到指定元素的集合

    /// </summary>

    /// <typeparam name="T"></typeparam>

    /// <param name="depObj"></param>

    /// <returns></returns>

    public static IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj)

        where T : DependencyObject

    {

        if (depObj != null)

        {

            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)

            {

                DependencyObject child = VisualTreeHelper.GetChild(depObj, i);

                if (child != null && child is T)

                {

                    yield return (T)child;

                }

 

                foreach (T childOfChild in FindVisualChildren<T>(child))

                {

                    yield return childOfChild;

                }

            }

        }

    }

}




public class FocusAdvancement    {        public static bool GetAdvancesByEnterKey(DependencyObject obj)        {            return (bool)obj.GetValue(AdvancesByEnterKeyProperty);        }          public static void SetAdvancesByEnterKey(DependencyObject obj, bool value)        {            obj.SetValue(AdvancesByEnterKeyProperty, value);        }          public static readonly DependencyProperty AdvancesByEnterKeyProperty =            DependencyProperty.RegisterAttached("AdvancesByEnterKey",typeof(bool),typeof(FocusAdvancement),            new UIPropertyMetadata(OnAdvancesByEnterKeyPropertyChanged));          static void OnAdvancesByEnterKeyPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)        {            var element = d as UIElement;            if (element == null)return;              if ((bool)e.NewValue) element.KeyDown += Keydown;            else element.KeyDown -= Keydown;        }          static void Keydown(object sender, KeyEventArgs e)        {            if (!e.Key.Equals(Key.Enter))return;              var element = sender as UIElement;                         if (element != null) element.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));        }      }

xmlns:FOU="clr-namespace:WPFAppVM.AppViews.AppCustomViews"   <TextBox FOU:FocusAdvancement.AdvancesByEnterKey="True" Width="120"></TextBox> <TextBox IsReadOnly="True" FOU:FocusAdvancement.AdvancesByEnterKey="True" Width="120"></TextBox> <Button Height="30" Width="80" FOU:FocusAdvancement.AdvancesByEnterKey="True">保存</Button>