WinForm ListView虚拟模式加载数据 提高加载速度

将VirtualMode 属性设置为 true 会将 ListView 置于虚拟模式。控件不再使用Collection.Add()这种方式来添加数据，取而代之的是使用RetrieveVirtualItem（Occurs when the ListView is in virtual mode and requires a ListViewItem.）和CacheVirtualItems两个事件，单独使用RetrieveVirtualItem也可以，CacheVirtualItems这个事件主要是为了方便编程人员操作缓冲集合，其参数CacheVirtualItemsEventArgs有StartIndex和EndIndex两个属性在虚拟模式下。

　　在虚拟模式下，从缓冲之中获取所需的数据进行加载，性能会有很大提高。 在其他情况下，可能需要经常重新计算 ListViewItem 对象的值，对整个集合进行此操作将产生不可接受的性能。

示例代码：

using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace WinFormTest
{
    public partial class Form1 : Form
    {
        private List<ListViewItem> myCache;
        public Form1()
        {
            InitializeComponent();

            myCache = new List<ListViewItem>();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            listView1.View = View.Details;
            listView1.VirtualMode = true;

            listView1.RetrieveVirtualItem += new RetrieveVirtualItemEventHandler(listView1_RetrieveVirtualItem);

        }

        void listView1_RetrieveVirtualItem(object sender, RetrieveVirtualItemEventArgs e)
        {
            if (myCache != null )
            {
                e.Item = myCache[e.ItemIndex];
            }
            else
            {
                //A cache miss, so create a new ListViewItem and pass it back.
                int x = e.ItemIndex * e.ItemIndex;
                e.Item = new ListViewItem(x.ToString());
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            List<Student> list = GetStudentList();
            foreach (var item in list)
            {
                ListViewItem listViewItem = new ListViewItem();
                listViewItem.SubItems[].Text = item.Name;
                listViewItem.SubItems.Add(item.Sex);
                myCache.Add(listViewItem);
            }
            listView1.VirtualListSize = myCache.Count;
        }

        private List<Student> GetStudentList()
        {
            List<Student> list = new List<Student>();
            for (int i = ; i < ; i++)
            {
                Student stu = new Student { Name = "student" + i, Sex = "男" };
                list.Add(stu);
            }
            return list;
        }

        private void button2_Click(object sender, EventArgs e)
        {

            ListViewItem listItem = new ListViewItem();
            listItem.SubItems[].Text = "女";
            listItem.SubItems.Add("哈哈");
            myCache.Add(listItem);
            listView1.VirtualListSize = myCache.Count;
            listView1.Invalidate();
        }

    }

    public class Student
    {
        public string Sex { get; set; }
        public string Name { get; set; }
    }
}

子线程+虚拟模式操作listview

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Threading;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        private List<ListViewItem> myCache;
        private delegate void DispMSGDelegate(int index, string MSG);

        public Form1()
        {
            InitializeComponent();
            this.listView1.Columns.Add("编号", , HorizontalAlignment.Right);
            this.listView1.Columns.Add("姓名", , HorizontalAlignment.Right);
            myCache = new List<ListViewItem>();

        }      

        private void button1_Click(object sender, EventArgs e)
        {
            progressBar1.Maximum = ;
            Thread tWorkingThread = new Thread(Thread_DisplayMSG);
            //ChaosThreadList.Add(tWorkingThread);
            tWorkingThread.Start();

        }
        private void Thread_DisplayMSG()
        {
            List<Student> list = GetStudentList();
            int k = ;
            foreach (var item in list)
            {
                progressBar1.Value = k;
                k++;

                DispMsg(k, item.Name);
            }
            listView1.VirtualListSize = myCache.Count;
        }

        private void DispMsg(int iIndex, string strMsg)
        {
            if (this.listView1.InvokeRequired == false)                      //如果调用该函数的线程和控件lstMain位于同一个线程内
            {
                ListViewItem listViewItem = new ListViewItem();
                listViewItem.SubItems[].Text = iIndex.ToString();
                listViewItem.SubItems.Add(strMsg);
                myCache.Add(listViewItem);
            }
            else                                                        //如果调用该函数的线程和控件lstMain不在同一个线程
            {
                //通过使用Invoke的方法，让子线程告诉窗体线程来完成相应的控件操作
                DispMSGDelegate DMSGD = new DispMSGDelegate(DispMsg);

                //使用控件lstMain的Invoke方法执行DMSGD代理(其类型是DispMSGDelegate)
                this.listView1.Invoke(DMSGD, iIndex, strMsg);

            }
        }

        private List<Student> GetStudentList()
        {
            List<Student> list = new List<Student>();
            for (int i = ; i < ; i++)
            {
                Student stu = new Student { Name = "student" + i, Sex = "男" };
                list.Add(stu);
            }
            return list;
        }
        private void listView1_RetrieveVirtualItem(object sender, RetrieveVirtualItemEventArgs e)
        {
            if (myCache != null)
            {
                e.Item = myCache[e.ItemIndex];
            }
            else
            {
                //A cache miss, so create a new ListViewItem and pass it back.
                int x = e.ItemIndex * e.ItemIndex;
                e.Item = new ListViewItem(x.ToString());
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            listView1.View = View.Details;
            listView1.VirtualMode = true;

            listView1.RetrieveVirtualItem += new RetrieveVirtualItemEventHandler(listView1_RetrieveVirtualItem);
        }

    }
    public class Student
    {
        public string Sex { get; set; }
        public string Name { get; set; }
    }
}