<Window x:Class="scrollviewr_drag.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:scrollviewr_drag"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
   <Grid>
       <Grid.RowDefinitions>
           <RowDefinition Height="30px"></RowDefinition>
           <RowDefinition Height="*"></RowDefinition>
       </Grid.RowDefinitions>
        <TextBlock x:Name="postion" HorizontalAlignment="Left" FontSize="24"></TextBlock>
        <ScrollViewer Margin="20" Grid.Row="1" HorizontalScrollBarVisibility="Visible"
                     VerticalScrollBarVisibility="Visible"
                     x:Name="scroller"
                     >
           <ScrollViewer.Style>
               <Style TargetType="ScrollViewer">
                   <Style.Triggers>
                        <Trigger Property="ScrollViewer.IsMouseCaptured" Value="True">
                            <Setter Property="Cursor" Value="Hand"></Setter>
                        </Trigger>
                   </Style.Triggers>
               </Style>
           </ScrollViewer.Style>
            <Canvas Background="Gainsboro" Width="2000" Height="2000" x:Name="content"  MouseMove="UIElement_OnMouseMove" MouseLeftButtonDown="Content_OnMouseLeftButtonDown"
                MouseLeftButtonUp="Content_OnMouseLeftButtonUp"></Canvas>
       </ScrollViewer>
   </Grid>
    
</Window>

using System;
using System.Collections.Generic;
using System.IO;
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.Resources;


namespace scrollviewr_drag
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        /// <summary>
        /// 用于记录鼠标按下的点
        /// </summary>
        private Point _clickPoint = new Point(0, 0);

        public MainWindow()
        {
            InitializeComponent();
            this.Loaded += MainWindow_Loaded;
        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            Random rand = new Random();
            rand.Next(0, 800);
            for (int i = 0; i < 1000; i++)
            {
                TextBlock t = new TextBlock();
                t.FontSize = 20;
                t.Text = i.ToString();

                content.Children.Add(t);
                Canvas.SetLeft(t, rand.Next(0, 2000));
                Canvas.SetTop(t, rand.Next(0, 2000));
            }
            //_clickPoint = new Point(scroller.ActualWidth / 2, scroller.ActualWidth);
        }

        private void UIElement_OnMouseMove(object sender, MouseEventArgs e)
        {
            if (e.LeftButton == MouseButtonState.Pressed)
            {
              
                Canvas cabSender = (Canvas)sender;
                //_clickPoint=new Point(scroll.ActualWidth/2,scroll.ActualHeight/2); 
                double x;
                double y;
                Point p = e.MouseDevice.GetPosition(cabSender);

                x = _clickPoint.X - p.X;
                y = _clickPoint.Y - p.Y;
                
                postion.Text = $"({x},{y})";

                scroller.ScrollToHorizontalOffset(scroller.HorizontalOffset+x);

                scroller.ScrollToVerticalOffset(scroller.VerticalOffset+y);

                

            }
        }


        private void Content_OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            _clickPoint = e.GetPosition((Canvas)sender);
            this.Cursor = Cursors.Hand;
        }

        private void Content_OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            this.Cursor = Cursors.Arrow;
        }
    }
}