WPF 在列表框中实现橡皮筋类型选择答案

【问题标题】：WPF implementing a rubberband type selection within a listboxWPF 在列表框中实现橡皮筋类型选择
【发布时间】：2009-09-03 14:11:09
【问题描述】：

我正在尝试允许用户希望选择Listbox 中的项目的橡皮筋或套索类型选择。我的Listbox 在网格中，我在网格中添加了一个控件，该控件在我要选择的区域上绘制一个矩形。我已经尝试测试Listbox 项目以查看它们是否在矩形内，但它们似乎都返回它们没有。在查看这些项目的VisualTreeHelper.GetDescendantBounds 时（就像我对矩形所做的那样，得到它的 X,Y）它总是将每个项目的 X,Y 返回为 0,0。我在命中测试方面做错了什么？

【问题讨论】：

标签： listbox selection hittest rubber-band

【解决方案1】：

您可以使用此代码获取 UIElement 相对于另一个 UIElement 的位置和边界。代码取自this post。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

public static class UIHelper
{
    public static Boolean GetUIElementCornersRelativTo(UIElement Base,
                                                UIElement RelativeTo,
                                                ref Point TopLeft,
                                                ref Point BottomLeft,
                                                ref Point BottomRight,
                                                ref Point TopRight,
                                                ref String Message)
    {
        try
        {
            if (Base == null)
            {
                throw new Exception("Base UIElement is null");
            }
            if (RelativeTo == null)
            {
                throw new Exception("RelativTo UIElement is null");
            }

            TopLeft = Base.TranslatePoint(new Point(0, 0), RelativeTo);
            BottomLeft = Base.TranslatePoint(new Point(0, Base.RenderSize.Height), RelativeTo);
            BottomRight = Base.TranslatePoint(new Point(Base.RenderSize.Width, Base.RenderSize.Height), RelativeTo);
            TopRight = Base.TranslatePoint(new Point(Base.RenderSize.Width, 0), RelativeTo);

            Message = "OK";
            return true;
        }
        catch (Exception ex)
        {
            Message = ex.Message;
            return false;
        }
    }
    public static Boolean GetPointRelativTo(UIElement Base,
                                     UIElement RelativeTo,
                                     Point ToProjectPoint,
                                     ref Point Result,
                                     ref String Message)
    {
        try
        {
            if (Base == null)
            {
                throw new Exception("Base UIElement is null");
            }
            if (RelativeTo == null)
            {
                throw new Exception("RelativTo UIElement is null");
            }

            if (ToProjectPoint == null)
            {
                throw new Exception("To project point is null");
            }

            Result = Base.TranslatePoint(ToProjectPoint, RelativeTo);

            Message = "OK";
            return true;
        }
        catch (Exception ex)
        {
            Message = ex.Message;
            return false;
        }
    }
}

【讨论】：