wpf内 canvs动态加载多张图片的问题

Question

我写了一个wpf程序,主要实现 把用户选择的图片加载到窗体,并能随意拖动图片,加载的代码写在了菜单的click事件里,这样就带来一个问题,当用户选择多个大点的图片时,程序的 UI就会出现无响应的.希望有人能帮我想想可行的解决办法,谢谢!以下是实现代码
windows1.xaml<Window x:Class="GetPicWave.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="图片摆放" Width="300" Height=" 300" 
         MouseLeftButtonUp="Window_MouseLeftButtonUp"
        MouseMove="Window_MouseMove"
        Icon="app.ico" 
        Background="AliceBlue" 
        >
    
    <Window.ContextMenu>
        <ContextMenu>
            <MenuItem Header="open" Click="MenuItem_Click"/>
            <Separator />
            <MenuItem Header="Clear" Click="MenuItem_Click_1" />
            <Separator />
            <MenuItem Header="Close" Click="MenuItem_Click_2" />
        </ContextMenu>
    </Window.ContextMenu>
  
        
       <Canvas Name="canvas">
        
    </Canvas> 
 
    
</Window>windows1.xaml.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
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;
using System.Windows.Forms;
using System.Threading;
using System.ComponentModel;namespace GetPicWave
{
    /// <summary>
    /// Window1.xaml 的交互逻辑
    /// </summary>
    public partial class Window1 : Window
    {
        UIElement uiOnDrag = null ;
        bool bIsDraging = false;
        double  ix, iy;        public Window1()
        {
            InitializeComponent();        }
     
        private void MenuItem_Click(object sender, RoutedEventArgs e)
        {            //打开文件
            OpenFileDialog openFileDialog1 = new OpenFileDialog();            openFileDialog1.InitialDirectory = "d:\\";
            openFileDialog1.Filter = "图片 files (*.jpg)|*.jpg|All files (*.*)|*.*";
            openFileDialog1.FilterIndex = 1;
            openFileDialog1.RestoreDirectory = true;
            openFileDialog1.Multiselect = true;            if (openFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                try
                {
                    Random rnd = new Random(100);
                    Int32 ic = 0;
                    foreach (string fullname in openFileDialog1.FileNames)
                    {
                        Uri url = new Uri(fullname);
                        BitmapImage bmp = new BitmapImage(url);
                        Image img = new Image();
                        img.Source = bmp;                        img.Width = 400;
                        img.Height = 300;                        canvas.Children.Add(img);
                        ic = rnd.Next(800);
                        Canvas.SetLeft(img, ic);
                        ic = rnd.Next(600);
                        Canvas.SetTop(img, ic);
                        img.MouseLeftButtonDown += Window_MouseLeftButtonDown;
                    }                }
                catch (Exception ex)
                {
                    System.Windows.MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message);
                }
                
            }
  
        }        
     
        private void Window_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            uiOnDrag = e.Source as UIElement;
           // Image tempImg = e.Source as Image;
            Int32 i = 1;
            foreach (UIElement uiETemp in canvas.Children)
            {
                if (i < Canvas.GetZIndex(uiETemp)) i = Canvas.GetZIndex(uiETemp);
            }
            i++;
            Canvas.SetZIndex(uiOnDrag, i);
            
            bIsDraging = true;
            ix = e.GetPosition(canvas ).X;
            iy = e.GetPosition(canvas).Y;
        }        private void Window_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            bIsDraging = false;
        }        private void Window_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
        {
            if (!bIsDraging) return;
            e.GetPosition(canvas);
            object xx = uiOnDrag.GetValue(Canvas.LeftProperty);
            object yy = uiOnDrag.GetValue(Canvas.TopProperty);
            double x = (double)xx;
            double y = (double)yy;
            uiOnDrag.SetValue(Canvas.LeftProperty, x + (e.GetPosition(canvas).X - ix));
            uiOnDrag.SetValue(Canvas.TopProperty, y + (e.GetPosition(canvas).Y - iy));            ix = e.GetPosition(canvas).X;
            iy = e.GetPosition(canvas).Y;
        }        private void MenuItem_Click_1(object sender, RoutedEventArgs e)
        {
            canvas.Children.Clear();
        }        private void TextBlock_MouseDown(object sender, MouseButtonEventArgs e)
        {
            DragMove();
        }        private void MenuItem_Click_2(object sender, RoutedEventArgs e)
        {
            Close();
        }
    }
}