listbox demo

功能

添加、删除、修改选中的项、上移、下移、清空、保存列表、加载列表、判断内容是否重复、查找、模糊查找、取消选择、上一条、下一条、第一条、最后一条

下载地址：https://download.csdn.net/download/u012663700/11994849

 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 ListBoxDemo
 {
     public partial class Form1 : Form
     {
         public Form1()
         {
             InitializeComponent();
         }

         private void Form1_Load(object sender, EventArgs e)
         {
             SetupButtonEnabled();
         }

         //设置按钮的可用和不可用
         private void SetupButtonEnabled()
         {
             string s = textBox1.Text.Trim();
             int i = listBox1.SelectedIndex;
             int count = listBox1.Items.Count;

             //添加
             btnAdd.Enabled = !listBox1.Items.Contains(s) && s.Length >  && !s.Contains(",");

             //删除
             btnDel.Enabled = i != -;

             //重命名
             btnRename.Enabled = i != - && listBox1.Items[i].ToString() != s;

             //上移
             btnMoveUp.Enabled = i -  >= ;

             //下移
             btnMoveDown.Enabled = i +  < listBox1.Items.Count && i != -; 

             //第一条
             btnFirst.Enabled = count >  && i != ;

             //最后一条
             btnLast.Enabled = i != count - ; 

             //上一条
             btnPre.Enabled = count >  && i !=  && i != -;

             //下一条
             btnNext.Enabled = i != count -  && i != -;

             //搜索
             btnFind.Enabled = textBox1.Text.Trim().Length > ;

             //模糊搜索
             btnFind1.Enabled = btnFind.Enabled;

             //取消选择
             btn取消选择.Enabled = i != -;
         }

         private void 添加文本_Click(object sender, EventArgs e)
         {
             string s = textBox1.Text.Trim();
             if (s == "")
             {
                 MessageBox.Show("内容不能为空或空格", "操作取消", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
             }
             else
             {
                     /*
                      * 不添加列表中已经存在的内容，
                      */
                 listBox1.Items.Add(s);
             }
             textBox1.Text = "";
             textBox1.Focus();
         }

         private void 修改选中的项_Click(object sender, EventArgs e)
         {
             /*
              * 可以通过这样直接修改指定的项的值   listBox1.Items[i] = "指定值";
              *
              */
             string s = textBox1.Text;
             int i = listBox1.SelectedIndex;
             if (i != -)
             {
                 if (listBox1.Items[i].ToString() != s)
                 {
                     listBox1.Items[i] = s;

                     s = listBox1.Items[i].ToString();
                 }
                 else
                 {
                     MessageBox.Show("名字相同", "不用重新命名", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                 }
             }
         }

         private void 删除选中的项_Click(object sender, EventArgs e)
         {
             /*
              * 这里的操作是 一次只删除一项
              */
             int i = listBox1.SelectedIndex;
             if (i != -)
             {
                 DialogResult d = MessageBox.Show("是否确定删除该分组？", "删除操作", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
                 if (d == DialogResult.Yes)
                 {
                     listBox1.Items.RemoveAt(i);
                     textBox1.Text = "";

                     if (listBox1.Items.Count >   )
                     {
                         if (i == listBox1.Items.Count)  //这一句是避免抛出异常
                         {
                             i = ;
                         }
                         listBox1.SelectedIndex = i;
                         listBox1.Focus();
                     }
                 }
             }
         }

         public static void Swap(ref string a, ref string b)
         {
             string c = a;
             a = b;
             b = c;
         }

         /*
          *  上移 和下移 实际上是交换2个数值
          *  上移就是[当前选中]的项和 [上一个项] 对换下值
          *  下移就是[当前选中]的项和 [下一个项] 对换下值
          *
          */

         private void btnMoveUp_Click(object sender, EventArgs e)
         {
             //[上移]
             string s = textBox1.Text;
             int i = listBox1.SelectedIndex;
             if (i != -)
             {
                 if (i -  >= )
                 {
                     string a = listBox1.Items[i].ToString();
                     string b = listBox1.Items[i - ].ToString();
                     Swap(ref a, ref b);
                     listBox1.Items[i] = a;
                     listBox1.Items[i - ] = b;
                     listBox1.SelectedIndex = i - ;
                 }
             }
         }

         private void btnMoveDown_Click(object sender, EventArgs e)
         {
             //[下移]
             string s = textBox1.Text;
             int i = listBox1.SelectedIndex;
             if (i != -)
             {
                 if (i +  < listBox1.Items.Count)
                 {
                     string a = listBox1.Items[i].ToString();
                     string b = listBox1.Items[i + ].ToString();
                     Swap(ref a, ref b);
                     listBox1.Items[i] = a;
                     listBox1.Items[i + ] = b;
                     listBox1.SelectedIndex = i + ;
                 }
             }
         }

         private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
         {
             object obj = listBox1.SelectedItem;
             string s = obj != null ? obj.ToString() : ""; //listbox如果没有选中则返回null
             textBox1.Text = s;
             SetupButtonEnabled();
         }

         private void textBox1_TextChanged(object sender, EventArgs e)
         {
             //当文本框中的内容和选中的内容一样则不用重命名
             SetupButtonEnabled();
         }

         //用来存放listBox的内容
         string myStr = "";
         private void btnSave_Click(object sender, EventArgs e)
         {
             /*
              * 将listBox的值转换成这种格式 aa,bb,cc,ddd,ee,ff 然后写入文件
              *  ,为分割符，为了避免把逗号号进来， SetupButtonEnabled中设置了如果内容包含,则不能添加
              */
             string s = "";
             StringBuilder sb = new StringBuilder();
             int length = listBox1.Items.Count;
             for (int i = ; i < length; i++)
             {
                 s = listBox1.Items[i].ToString();
                 sb.Append(s + ",");
             }
             s = sb.ToString();
             if (s.EndsWith(","))
                 s = s.Substring(, s.Length - );
             myStr = s;
             MessageBox.Show(s);
         }

         private void btnRead_Click(object sender, EventArgs e)
         {
             /*
              * 读取
              * 将这样的 aa,bb,cc,ddd,ee,ff  字符串 转换成字符串数组然后 添加到listBox中
              */
             string[] arr = myStr.Split(new char[] { ',' });
             listBox1.Items.Clear();
             listBox1.Items.AddRange(arr);
         }

         private void listBox1_MouseDown(object sender, MouseEventArgs e)
         {
             //双击删除选中的项
             int i = listBox1.SelectedIndex;
             if (i != -)
             {
                 if (e.Clicks == )
                 {
                     listBox1.Items.RemoveAt(i);
                 }
             }
         }

         private void 清空_Click(object sender, EventArgs e)
         {   //清空
             listBox1.Items.Clear();
         }

         private void 第一条_Click(object sender, EventArgs e)
         {
             if (listBox1.Items.Count > )
             {
                 listBox1.SelectedIndex = ;
                 label1.Text = listBox1.SelectedItem.ToString();
             }

             SetupButtonEnabled();
         }

         private void 上一条_Click(object sender, EventArgs e)
         {
             if (listBox1.SelectedIndex -  >= )
             {
                 int i = listBox1.SelectedIndex;
                 i--;
                 listBox1.SelectedIndex = i;

                 label1.Text = listBox1.SelectedItem.ToString();
             }
             SetupButtonEnabled();
         }

         private void 下一条_Click(object sender, EventArgs e)
         {
             if (listBox1.SelectedIndex +  <= listBox1.Items.Count)
             {
                 int i = listBox1.SelectedIndex;
                 i++;
                 listBox1.SelectedIndex = i;

                 label1.Text = listBox1.SelectedItem.ToString();
             }
             SetupButtonEnabled();
         }

         private void 最后一条_Click(object sender, EventArgs e)
         {
             if ( listBox1.Items.Count >)
             {
                 listBox1.SelectedIndex = listBox1.Items.Count - ;
                 label1.Text = listBox1.SelectedItem.ToString();
             }
             SetupButtonEnabled();
         }

         private void 查找内容_Click(object sender, EventArgs e)
         {
             /*精确搜索*/
             string s = textBox1.Text;
             int i = listBox1.Items.IndexOf(s);   // int i = listBox1.FindStringExact(s);
             if (i != -)
             {
                 listBox1.SelectedIndex = i;
             }
             else
             {
                 MessageBox.Show("列表中没有此项");
             }
         }

         private void 模糊查询_Click(object sender, EventArgs e)
         {
             //模糊查询  只要项目包含关键字就行
             string s = textBox1.Text;
             bool b = false;
             for (int i = ; i < listBox1.Items.Count; i++)
             {
                 b = false;
                 string x = listBox1.Items[i].ToString();
                 if (x.Contains(s))
                 {
                     listBox1.SelectedIndex = i;
                     b = true;
                     break;
                 }
             }
             if (b == false)
             {
                 MessageBox.Show("列表中没有此项");
             }
         }

         private void button1_Click(object sender, EventArgs e)
         {
             listBox1.SelectedIndex = -;
         }
     }
 }