WPF canvas内部拖动控件的时候关于不能拖到边界外面的问题，该控件还用装饰器

2017-09-29 11:42:46 820 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

WPF实现图片标注功能：基于Adorner装饰器的可拖动、可缩放矩形框设计与边界控制本文详细介绍了在WPF中利用Adorner装饰器实现图片标注功能的核心方法。通过自定义CanvasAdorner，为矩形框添加可拖动的缩放手柄，并实现了严格的边界控制，确保标注框始终位于图片区域内。该方案实现了UI交互与显示逻辑的清晰分离，代码可维护性高，是构建图像标注、截图工具等应用的理想选择。阅读详情

private void LeftMouseButtonDowm_Body(object sender, MouseButtonEventArgs e)
{
if (e.ClickCount > 1 && _adornedElement is TreeView)
{
TreeView ctrl = _adornedElement as TreeView;
_body.IsHitTestVisible = false;
ctrl.IsHitTestVisible = true;
Keyboard.Focus(ctrl);
return;
}
_startLocation = new Point((double)_adornedElement.GetValue(Canvas.LeftProperty), (double)_adornedElement.GetValue(Canvas.TopProperty));
_startHeight = (double)AdornedElement.GetValue(FrameworkElement.HeightProperty);
_startWidth = (double)AdornedElement.GetValue(FrameworkElement.WidthProperty);
_dragLocation = Mouse.GetPosition(_canvas);
_isDraging = true;
(sender as Rectangle).CaptureMouse();
}
private void MouseMove_Body(object sender, MouseEventArgs e)
{
if (_isDraging)
{
Point parentCanvas = Mouse.GetPosition(_canvas);
if (parentCanvas.X >= 15)
{
_adornedElement.SetValue(Canvas.LeftProperty, _startLocation.X + (parentCanvas.X - _dragLocation.X));
_adornedElement.SetValue(Canvas.TopProperty, _startLocation.Y + (parentCanvas.Y - _dragLocation.Y));
}
}
}