WPF 用代码实现WrapPanel右侧自动对齐（解决多余空白问题）

<Border  Background="{StaticResource BorderBg}"  BorderThickness="2" BorderBrush="{StaticResource BorderBrush}" CornerRadius="5" Padding="5"   x:Name="SvKeyWords" Margin="142,0,134,58" Height="175" VerticalAlignment="Bottom" Visibility="Collapsed"  Opacity="0.98">
       <ScrollViewer VerticalScrollBarVisibility="Auto" >
            <WrapPanel x:Name="WpKeyWords"/>
       </ScrollViewer>
 </Border>

        private void AlignWrapPanelChild()
        {
            //WrapPanel 所有子元素
            var lst = (from object child in WpKeyWords.Children select child as Border).ToList();
            if (lst.Count > 1)
            {
                //每次 重置 子元素宽度
                foreach (var t in lst)
                {
                    t.Width = double.NaN;
                    t.UpdateLayout();
                }

                for (var i = 0; i < lst.Count - 1; i++)
                {
                    //找到每行最后一个子元素
                    var child = lst[i];
                    var nxtChild = lst[i + 1];
                    var plWidth = WpKeyWords.ActualWidth;
                    var childPoint = child.TranslatePoint(new Point(0, 0), WpKeyWords);
                    var nxtChildPoint = nxtChild.TranslatePoint(new Point(0, 0), WpKeyWords);
                    if (nxtChildPoint.X < childPoint.X)
                    {
                        //找出同一行的子元素
                        var tempLst = lst.Where(b => b.TranslatePoint(new Point(0, 0), WpKeyWords).Y.Equals(childPoint.Y)).ToList();
                        //算出多余的空白宽度
                        var surplusWidth = plWidth - childPoint.X - child.Margin.Right - child.ActualWidth;
                        var averageAddWidth = surplusWidth / tempLst.Count;
                        //将多余的宽度平均分给当前行每个子元素
                        foreach (var b in tempLst)
                        {
                            b.Width = b.ActualWidth + averageAddWidth;
                            b.UpdateLayout();
                        }
                    }

                }
            }
        }

private void do()
{
    ……
    WpKeyWords.SizeChanged += delegate { AlignWrapPanelChild(); };
    AlignWrapPanelChild();
}