Windows Phone 系列 使用 MVVM绑定时无法获取当前值

在使用 MVVM绑定时无法获取当前值

后来发现一个方法，就是在changed事件中更新绑定

如：textbox

private void tbsearchCard_TextChanged(object sender, TextChangedEventArgs e)
        {
            UpdateTextBoxSource(sender);
        }

        public void UpdateTextBoxSource(object sender)
        {

            if (sender is TextBox)
            {
                TextBox tb = sender as TextBox;




                BindingExpression binding = tb.GetBindingExpression(TextBox.TextProperty);
                if (binding != null)
                    binding.UpdateSource();
            }

        }

如：Pivot

      private void pvtSearch_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (sender is  Pivot)
            {
                Pivot pvt = sender as Pivot;

 
                BindingExpression binding = pvt.GetBindingExpression(Pivot.SelectedIndexProperty);
                if (binding != null)
                    binding.UpdateSource();
            }
        }

OK