wpf拖拽封装类

<UserControl x:Class="WpfApplication1.DragItem"

             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" 

             mc:Ignorable="d" MouseDown="UserControl_MouseDown_1">

    <Grid Background="#FF191919" HorizontalAlignment="Center" VerticalAlignment="Center">

        <Label  Content="项目文字" Foreground="White" FontSize="16" Width="450" Height="36" VerticalContentAlignment="Center" BorderThickness="2" BorderBrush="#FF424242"/>

    </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 WpfApplication1

{

    /// <summary>

    /// DragItem.xaml 的交互逻辑

    /// </summary>

    public partial class DragItem : UserControl

    {

        public static Point dragDownMousePoint;

        public static Point dragDownControlPoint;



        public DragItem()

        {

            InitializeComponent();

        }



        public DragItem(string content)

        {

            InitializeComponent();

            this.Content.Content = content;   

        }



        private void mouseMove(object sender, MouseEventArgs e)

        {

            Window w = Window.GetWindow(this);

            Point p = e.GetPosition(w);



            double moveX = p.X - dragDownMousePoint.X;

            double moveY = p.Y - dragDownMousePoint.Y;



            Point targetPoint = new Point(dragDownControlPoint.X + moveX, dragDownControlPoint.Y + moveY);

            if (double.IsNaN(dragDownControlPoint.X))

            {

                targetPoint.X = moveX;

            }

            if (double.IsNaN(dragDownControlPoint.Y))

            {

                targetPoint.Y = moveY;

            }



            Canvas parent = (Canvas)this.Parent;



            if (targetPoint.X < 0)

            {

                Canvas.SetLeft(this, 0);

            }

            else if (targetPoint.X + this.ActualWidth > parent.ActualWidth)

            {

                Canvas.SetLeft(this, parent.ActualWidth - this.ActualWidth);

            }

            else

            {

                Canvas.SetLeft(this, targetPoint.X);

            }



            if (targetPoint.Y< 0)

            {

                Canvas.SetTop(this, 0);

            }

            else if (targetPoint.Y + this.ActualHeight > parent.ActualHeight)

            {

                Canvas.SetTop(this, parent.ActualHeight - this.ActualHeight);

            }

            else

            {

                Canvas.SetTop(this, targetPoint.Y);

            }

            Console.WriteLine(targetPoint.X + this.ActualWidth + "    " + parent.ActualWidth);

        }



        private void mouseUp(object sender, MouseEventArgs e)

        {

            Mouse.RemoveMouseMoveHandler(Window.GetWindow(this), mouseMove);

            Mouse.RemoveMouseUpHandler(Window.GetWindow(this), mouseUp);

            Mouse.Capture(null);

        }



        private void UserControl_MouseDown_1(object sender, MouseButtonEventArgs e)

        {

            Point p = e.GetPosition(Window.GetWindow(this));

            dragDownMousePoint = p;

            dragDownControlPoint = new Point(Canvas.GetLeft(this), Canvas.GetTop(this));



            Mouse.AddMouseMoveHandler(Window.GetWindow(this), mouseMove);

            Mouse.AddMouseUpHandler(Window.GetWindow(this), mouseUp);

            Mouse.Capture(this);

        }



        private void Label_Loaded_1(object sender, RoutedEventArgs e)

        {



        }

    }

}