WPF 截图控件之移除控件(九)「仿微信」
WPF 截图控件之移除控件(九)「仿微信」
作者:WPFDevelopersOrg
原文链接: https://github.com/WPFDevelopersOrg/WPFDevelopers
正文
一、前几篇实现了添加 方框、椭圆、箭头 此时需要删除所添加的操作和撤销上次操作。
1)选中操作
- 在添加方框、椭圆、箭头、画笔、文字的同时需要设置Tag=Draw用于标记是操作的痕迹 实现MouseLeftButtonDown事件。
- 监听到操作MouseLeftButtonDown事件后循环VisualTreeHelper.GetChildren获取返回指定可视对象包含的子级个数。判断Tag==Draw设置其Opacity=1清除上次选择。
- 用一个变量存放当前选择的操作使用FrameworkElement,然后设置当前内容Opacity=0.7
- //箭头
- controlArrow.MouseLeftButtonDown += (s, e) =>
- {
- SelectElement();
- frameworkElement = s as Control;
- frameworkElement.Opacity = .7;
- };
- //方框
- borderRectangle.MouseLeftButtonDown += (s, e) =>
- {
- SelectElement();
- frameworkElement = s as Border;
- frameworkElement.Opacity = .7;
- };
- //椭圆
- drawEllipse.MouseLeftButtonDown += (s, e) =>
- {
- SelectElement();
- frameworkElement = s as Ellipse;
- frameworkElement.Opacity = .7;
- };
- //文字
- textBorder.PreviewMouseLeftButtonDown += (s, e) =>
- {
- _radioButtonText.IsChecked = true;
- _radioButtonText_Click(null,null);
- SelectElement();
- var border = s as Border;
- frameworkElement = border;
- frameworkElement.Opacity = .7;
- border.BorderThickness = new Thickness(1);
- };
- //画笔
- polyLine.MouseLeftButtonDown += (s, e) =>
- {
- _radioButtonInk.IsChecked = true;
- _radioButtonInk_Click(null, null);
- SelectElement();
- frameworkElement = s as Polyline;
- frameworkElement.Opacity = .7;
- };
- void SelectElement()
- {
- for (int i = 0; i < VisualTreeHelper.GetChildrenCount(_canvas); i++)
- {
- var child = VisualTreeHelper.GetChild(_canvas, i);
- if (child is FrameworkElement frameworkElement && frameworkElement.Tag != null)
- if (frameworkElement.Tag.ToString() == _tag)
- frameworkElement.Opacity = 1;
- }
- }
复制代码 2)删除操作 按下Delete键删除。复制代码 3)撤销操作 按下Ctrl+Z 撤销上次操作。- if (e.KeyStates == Keyboard.GetKeyStates(Key.Z) && Keyboard.Modifiers == ModifierKeys.Control)
- {
- if (_canvas.Children.Count > 0)
- _canvas.Children.Remove(_canvas.Children[_canvas.Children.Count - 1]);
- }
复制代码 完整代码如下
项目地址
- 框架名:WPFDevelopers
- 作者:WPFDevelopers
- GitHub
- Gitee
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