WPF 用鼠标移动元素

我正在尝试在 WPF 应用程序中用鼠标移动按钮。

XAML Grid 是结构的根：

<Grid Name="MyGrid"            >
    <Button Name="Samplebutton"
            PreviewMouseDown="Samplebutton_PreviewMouseDown"
            PreviewMouseUp="Samplebutton_PreviewMouseUp"
            PreviewMouseMove="Samplebutton_PreviewMouseMove"
            Content="Moving" Width="100" Height="35"/>
</Grid>

和后面的代码：

private bool _isMoving;


private void Samplebutton_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
    _isMoving = true;
}

private void Samplebutton_PreviewMouseUp(object sender, MouseButtonEventArgs e)
{
    _isMoving = false;
}

private void Samplebutton_PreviewMouseMove(object sender, MouseEventArgs e)
{
    if (!_isMoving) return;

    TranslateTransform transform = new TranslateTransform();
    transform.X = Mouse.GetPosition(MyGrid).X;
    transform.Y = Mouse.GetPosition(MyGrid).Y;
    this.Samplebutton.RenderTransform = transform;
}

第一次点击按钮将他移到很远的地方，然后我可以移动按钮，但这是第一次按钮被移开。我缺少什么？

这是一个旧帖子，但是（我认为）这是一个更好的方法：

我认为你不应该使用布尔值来检查鼠标是否正在拖动当前控件。另外，使用PreviewMouse....是获取鼠标位置的无用修复（当鼠标不在控件上方时）

你应该捕获鼠标。当您捕获鼠标时，即使鼠标不在控件上方，仍然会引发 mouse_move 事件（即使关闭当前窗口）。我认为这才是应该做的。它更简单、更容易阅读。

这是代码：

public partial class VisualBlock : UserControl
{
    private Point _positionInBlock;

    public VisualBlock()
    {
        InitializeComponent();
    }

    private void UserControl_MouseDown(object sender, MouseButtonEventArgs e)
    {
        // when the mouse is down, get the position within the current control. (so the control top/left doesn't move to the mouse position)
        _positionInBlock = Mouse.GetPosition(this);

        // capture the mouse (so the mouse move events are still triggered (even when the mouse is not above the control)
        this.CaptureMouse();
    }

    private void UserControl_MouseMove(object sender, MouseEventArgs e)
    {
        // if the mouse is captured. you are moving it. (there is your 'real' boolean)
        if (this.IsMouseCaptured)
        {
            // get the parent container
            var container = VisualTreeHelper.GetParent(this) as UIElement;

            if(container == null)
                return;
            
            // get the position within the container
            var mousePosition = e.GetPosition(container);

            // move the usercontrol.
            this.RenderTransform = new TranslateTransform(mousePosition.X - _positionInBlock.X, mousePosition.Y - _positionInBlock.Y);
        }
    }

    private void UserControl_MouseUp(object sender, MouseButtonEventArgs e)
    {
        // release this control.
        this.ReleaseMouseCapture();
    }
}

Update:

如果您有一个窗口，例如带有画布，则可以将此用户控件添加到画布中。

这是它的要点：WPF 移动控件

<Window x:Class="WPFTestControlMoveMouse.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WPFTestControlMoveMouse"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="30" />
            <RowDefinition />
        </Grid.RowDefinitions>

        <Button Grid.Row="0" Click="Button_Click">New</Button>
        <Canvas x:Name="MyCanvas" Grid.Row="1"></Canvas>
    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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;

namespace WPFTestControlMoveMouse
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            MyCanvas.Children.Add(new VisualBlock());
        }
    }
}

<UserControl x:Class="WPFTestControlMoveMouse.VisualBlock"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:WPFTestControlMoveMouse"
             mc:Ignorable="d" 
             Width="300" Height="200" MouseDown="UserControl_MouseDown" MouseUp="UserControl_MouseUp" MouseMove="UserControl_MouseMove">
    <Grid>
        <Border BorderBrush="Black" BorderThickness="1" Background="Silver" />
        <TextBlock FontSize="48" HorizontalAlignment="Center" VerticalAlignment="Center">Hi there!!</TextBlock>
    </Grid>
</UserControl>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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;

namespace WPFTestControlMoveMouse
{
    /// <summary>
    /// Interaction logic for VisualBlock.xaml
    /// </summary>
    public partial class VisualBlock : UserControl
    {
        private Point _positionInBlock;

        public VisualBlock()
        {
            InitializeComponent();
        }

        private void UserControl_MouseDown(object sender, MouseButtonEventArgs e)
        {
            // when the mouse is down, get the position within the current control. (so the control top/left doesn't move to the mouse position)
            _positionInBlock = Mouse.GetPosition(this);

            // capture the mouse (so the mouse move events are still triggered (even when the mouse is not above the control)
            this.CaptureMouse();
        }

        private void UserControl_MouseMove(object sender, MouseEventArgs e)
        {
            // if the mouse is captured. you are moving it. (there is your 'real' boolean)
            if (this.IsMouseCaptured)
            {
                // get the parent container
                var container = VisualTreeHelper.GetParent(this) as UIElement;

                // get the position within the container
                var mousePosition = e.GetPosition(container);

                // move the usercontrol.
                this.RenderTransform = new TranslateTransform(mousePosition.X - _positionInBlock.X, mousePosition.Y - _positionInBlock.Y);
            }
        }

        private void UserControl_MouseUp(object sender, MouseButtonEventArgs e)
        {
            // release this control.
            this.ReleaseMouseCapture();
        }
    }
}

通过从标签控件派生来用鼠标移动标签：

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

namespace WPFTestControlMoveMouse
{
    public class MyLabel : Label
    {
        private Point _positionInBlock;

        protected override void OnMouseDown(MouseButtonEventArgs e)
        {
            // when the mouse is down, get the position within the current control. (so the control top/left doesn't move to the mouse position)
            _positionInBlock = Mouse.GetPosition(this);

            // capture the mouse (so the mouse move events are still triggered (even when the mouse is not above the control)
            this.CaptureMouse();
        }

        protected override void OnMouseMove(MouseEventArgs e)
        {
            // if the mouse is captured. you are moving it. (there is your 'real' boolean)
            if (this.IsMouseCaptured)
            {
                // get the parent container
                var container = VisualTreeHelper.GetParent(this) as UIElement;

                // get the position within the container
                var mousePosition = e.GetPosition(container);

                // move the usercontrol.
                this.RenderTransform = new TranslateTransform(mousePosition.X - _positionInBlock.X, mousePosition.Y - _positionInBlock.Y);
            }
        }
        protected override void OnMouseUp(MouseButtonEventArgs e)
        {
            // release this control.
            this.ReleaseMouseCapture();
        }

    }
}