c# - 用鼠标在窗体上移动椭圆

Question

如何在WPF中用鼠标在窗口上移动椭圆。

private void ellipse_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
{
    Ellipse ellipse = sender as Ellipse;
    if (ellipse != null && e.LeftButton == MouseButtonState.Pressed)
    {
        DragDrop.DoDragDrop(ellipse,
                            ellipse.Fill.ToString(),
                            System.Windows.DragDropEffects.Copy);
    }
}

如何创建方法ellipse_MouseClick？

Answer 1

Ellipses 上没有 MouseClick 事件，但是有 MouseDown 和 MouseUp 事件。我假设您正在寻找这样的东西。

WPF:

<Window x:Class="WpfApplication.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Height="350" Width="525"
        MouseMove="Any_MouseMove"
        >
    <Canvas>
        <Ellipse Fill="Lavender" Height="100" Width="100" 
                 MouseLeftButtonDown="Ellipse_MouseLeftButtonDown" 
                 MouseLeftButtonUp="Ellipse_MouseLeftButtonUp" 
                 MouseMove="Any_MouseMove" />
    </Canvas>
</Window>

代码隐藏:

using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace WpfApplication
{
    public partial class MainWindow : Window
    {
        private UIElement _lastClickedUIElement;
        private Point? _clickOffset;

        public MainWindow() { InitializeComponent(); }

        private void Ellipse_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            _lastClickedUIElement = sender as UIElement;
            _clickOffset = e.GetPosition(_lastClickedUIElement);
        }

        private void Ellipse_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            _lastClickedUIElement = null;
        }

        private void Any_MouseMove(object sender, MouseEventArgs e)
        {
            if (_lastClickedUIElement == null)
                return;

            _lastClickedUIElement.SetValue(Canvas.LeftProperty, e.GetPosition(this).X - _clickOffset.Value.X);
            _lastClickedUIElement.SetValue(Canvas.TopProperty, e.GetPosition(this).Y - _clickOffset.Value.Y);
        }
    }
}

点击圆圈来移动它。只要您为它们提供这些方法，这将适用于任何 UI 元素。也可以随意在 Canvas 上添加一个矩形。

<Rectangle Fill="Lavender" Height="100" Width="100" 
         MouseLeftButtonDown="Ellipse_MouseLeftButtonDown" 
         MouseLeftButtonUp="Ellipse_MouseLeftButtonUp" 
         MouseMove="Any_MouseMove" />