c# - 移动 UIElement 时，wpf 相对于窗口的平移点会导致偏移

Question

我目前正在开发一个用于使用鼠标拖动 UIElement 的行为类。我以前做过类似的东西，但我试图做到这一点，以便 UIElement 不依赖于某种类型的父级(除了窗口之外)。

我面临的问题是当我尝试平移鼠标和 UIElement(AssociatedObject) 相对于窗口的坐标时，这导致了下面显示的偏移。

尝试添加偏移量来“修复”当前偏移量感觉像是作弊，并且会使创建其余的运动行为变得更加复杂。

目前我正在使用内部包含多个元素的网格来测试dragBehaviorComponentClass。(我用浅蓝色填充网格作为指示器，尽管它与其他形状略有重叠)

我目前只是尝试将 uiElement 的 0,0 位置附加到鼠标点，我还没有处理任何偏移以进一步改进拖动。

代码

public class MouseDragBehaviourComponent : Behavior<UIElement>
    {
        private TranslateTransform transform = new TranslateTransform();

        protected override void OnAttached()
        {
            AssociatedObject.MouseLeftButtonDown += AssociatedObject_MouseLeftButtonDown;
            AssociatedObject.PreviewMouseMove += AssociatedObject_PreviewMouseMove;
            AssociatedObject.MouseMove += AssociatedObject_MouseMove;
            AssociatedObject.MouseLeftButtonUp += AssociatedObject_MouseLeftButtonUp;
        }

        private void AssociatedObject_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            AssociatedObject.ReleaseMouseCapture();
        }
        private void AssociatedObject_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)

        {
            Point currentPosition = AssociatedObject.TranslatePoint(new Point(0, 0), Window.GetWindow(AssociatedObject));
            AssociatedObject.RenderTransform = transform;
            AssociatedObject.CaptureMouse();
        }

        private void AssociatedObject_MouseMove(object sender, MouseEventArgs e)
        {
            if (AssociatedObject.IsMouseCaptured)
            {
                Point mousePosition = e.GetPosition(Window.GetWindow(AssociatedObject));
                transform.X = mousePosition.X;
                transform.Y = mousePosition.Y;
            }

        }

xaml

<Setter Property="Template">
            <Setter.Value>
                <ControlTemplate  TargetType="{x:Type local:UISet}">
                    <Border >
                        <e:Interaction.Behaviors>
                            <bt:MouseDragBehaviourComponent/>
                        </e:Interaction.Behaviors>
                        <Grid Background="LightBlue">
                            <StackPanel>
                                <Path MouseLeftButtonDown="geometry_MouseLeftButtonDown" Name="geometry" Fill="Blue">
                                <Path.Data>
                                    <CombinedGeometry GeometryCombineMode="Exclude">
                                        <CombinedGeometry.Geometry1>
                                    <RectangleGeometry RadiusX="2" RadiusY="2" Rect="-5,-50,100,50" />
                                        </CombinedGeometry.Geometry1>
                                        <CombinedGeometry.Geometry2>
                                            <RectangleGeometry RadiusX="2" RadiusY="2" Rect="5,-40,90,40" />
                                        </CombinedGeometry.Geometry2>
                                    </CombinedGeometry>
                                </Path.Data>
                            </Path>
                            <Path MouseLeftButtonDown="geometry_MouseLeftButtonDown" Fill="Red">
                                <Path.Data>
                                    <PathGeometry>
                                        <PathFigure StartPoint="0,0">
                                            <LineSegment Point="5,6"/>
                                            <LineSegment Point="10,0"/>
                                            <LineSegment Point="0,0"/>
                                        </PathFigure>
                                    </PathGeometry>
                                </Path.Data>
                            </Path>
                        </StackPanel>
                    </Grid>

Answer 1

代码的设置方式:

transform.X = mousePosition.X;
transform.Y = mousePosition.Y;

获取您移动的物体内部的鼠标位置。这会导致变换远离鼠标，无论距离是多少。要解决这个问题，您需要获取要移动的物体的容器的鼠标位置(将作为主要点)，并获取要移动的物体内部光标的鼠标位置。这将充当偏移量。总而言之，代码看起来类似于:

Point mouseContainerLocation = Mouse.GetPosition(container);
Point mouseObjectLocation = Mouse.GetPosition(object);
transform.X = mouseContainerLocation.X - mouseObjectLocation.X;
transform.Y = mouseContainerLocation.Y - mouseObjectLocation.Y;

我在我制作的应用程序中做了类似的事情，这对我有用