listbox更新item的事件

Question

我想实现这么一件事，每当listbox中的item发生变化：增加减少或clear···就会触发一个事件，然后执行一堆代码~

本以为这会是一个很基础的事件，但是在listbox的事件表中查了半天也没有发现像的。有知道到底是哪一个事件的么？或者提供其他的解决办法？

Answer 1

确实没有，你可以通过这个方式：

【1、界面】

【2.代码】

namespace CSharp
{
    public partial class Form1 : Form
    {
        /// <summary>
        /// 自定义类
        /// </summary>
        private class MyBindingList<T> : BindingList<T>
        {
            /// <summary>
            /// 自定义删除事件
            /// </summary>
            public event Action<T> AfterRemoving = null;

            //重写删除事件
            protected override void RemoveItem(int index)
            {
                //先保留删除的东西
                T t = Items[index];
                //删除
                base.RemoveItem(index);
                //删除后触发事件
                if (AfterRemoving != null)
                {
                    AfterRemoving(t);
                }
            }

            protected override void ClearItems()
            {
                //在清楚前备份全部记录
                T[] tArray = new T[Items.Count];
                Items.CopyTo(tArray, 0);
                //删除全部记录
                base.ClearItems();
                //引发删除事件
                foreach (T item in tArray)
                {
                    AfterRemoving(item);
                }
            }
        }

        MyBindingList<string> stringList = null;

        public Form1()
        {
            InitializeComponent();
            stringList = new MyBindingList<string>();
            stringList.Add("a");
            stringList.Add("b");
            stringList.Add("c");
            //绑定添加事件
            stringList.ListChanged += new ListChangedEventHandler(stringList_ListChanged);
            stringList.AfterRemoving += new Action<string>(stringList_AfterRemoving);
            listBox1.DataSource = stringList;
        }

        void stringList_ListChanged(object sender, ListChangedEventArgs e)
        {
            if (e.ListChangedType == ListChangedType.ItemAdded)
            {
                MessageBox.Show(stringList[e.NewIndex]);
            }
        }

        void stringList_AfterRemoving(string obj)
        {
            MessageBox.Show("删除了：" + obj);
        }
    
        private void button1_Click(object sender, EventArgs e)
        {
            //添加记录
            stringList.Add("aa");
        }

        private void button2_Click(object sender, EventArgs e)
        {
            //清除全部记录
            stringList.Clear();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            //删除
            stringList.Remove("a");
        }

    }
}

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Answer 2

是否可尝试使用DataSet绑定ListBox，借用BindSource的ListChanged事件做点文章，可以达到增加、减少item的效果，而利用DataTable的TableCleared事件能达到clear的效果。粗略的代码如下：

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

namespace listbox
{
    public partial class Form1 : Form
    {
        public Form1()
        { 
            InitializeComponent();
            this.dataSet1.Tables[0].TableCleared += new DataTableClearEventHandler(Form1_TableCleared);
        }

        private void Form1_TableCleared(object sender, DataTableClearEventArgs e)
        {
            MessageBox.Show("CLR");
        }


        #region ADD_BUTTON
        private void button1_Click(object sender, EventArgs e)
        {
            if (this.textBox1.Text.ToString().Trim() == "")
                return;

            DataRow dr = this.dataSet1.Tables[0].NewRow();
            dr["COL"] = this.textBox1.Text.ToString();
            this.dataSet1.Tables[0].Rows.Add(dr);
            this.dataSet1.Tables[0].AcceptChanges();
        }
        #endregion

        private void dataTable1BindingSource_ListChanged(object sender, ListChangedEventArgs e)
        {
            if (e.ListChangedType == ListChangedType.ItemAdded)
            {
                MessageBox.Show("ADD");
            }

            if (e.ListChangedType == ListChangedType.ItemDeleted)
            {
                MessageBox.Show("DEL");
            }
        }

        #region DEL_BUTTON
        private void button2_Click(object sender, EventArgs e)
        {
            if (this.dataSet1.Tables[0].Rows.Count == 0)
                return;

            this.dataSet1.Tables[0].Rows.RemoveAt(this.dataTable1ListBox.SelectedIndex);
            this.dataSet1.Tables[0].AcceptChanges();
        }
        #endregion

        #region CLR_BUTTON
        private void button3_Click(object sender, EventArgs e)
        {
            this.dataSet1.Tables[0].Clear();
        }
        #endregion

    }
}

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Answer 3

dear

如果是我，我会用bindingSource

        private BindingList<string> _data = new BindingList<string>() { "1", "2", "3", "4" };
        private BindingSource _source = new BindingSource();
 
        private void Form1_Load(object sender, EventArgs e)
        {
            this._source.DataSource = this._data;
            this.listBox1.DataSource = this._source;
            this._source.ListChanged += new ListChangedEventHandler(_source_ListChanged);
        }
 
        private void _source_ListChanged(object sender, System.ComponentModel.ListChangedEventArgs e)
        {
            switch (e.ListChangedType)
            {
                case ListChangedType.Reset:
                    break;
                case ListChangedType.ItemAdded:
                    break;
                case ListChangedType.ItemDeleted:
                    break;
                case ListChangedType.ItemMoved:
                    break;
                case ListChangedType.ItemChanged:
                    break;
                case ListChangedType.PropertyDescriptorAdded:
                    break;
                case ListChangedType.PropertyDescriptorDeleted:
                    break;
                case ListChangedType.PropertyDescriptorChanged:
                    break;
                default:
                    throw new ArgumentOutOfRangeException();
            }
        }

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