listbox demo

  1 using System;
  2 using System.Collections.Generic;
  3 using System.ComponentModel;
  4 using System.Data;
  5 using System.Drawing;
  6 using System.Linq;
  7 using System.Text;
  8 using System.Windows.Forms;
  9 
 10 namespace ListBoxDemo
 11 {
 12     public partial class Form1 : Form
 13     {
 14         public Form1()
 15         {
 16             InitializeComponent();
 17         }
 18 
 19         private void Form1_Load(object sender, EventArgs e)
 20         {
 21             SetupButtonEnabled();
 22         }
 23 
 24         //设置按钮的可用和不可用
 25         private void SetupButtonEnabled()
 26         {
 27             string s = textBox1.Text.Trim();
 28             int i = listBox1.SelectedIndex;
 29             int count = listBox1.Items.Count;
 30 
 31             //添加
 32             btnAdd.Enabled = !listBox1.Items.Contains(s) && s.Length > 0 && !s.Contains(",");
 33 
 34             //删除
 35             btnDel.Enabled = i != -1;
 36 
 37             //重命名
 38             btnRename.Enabled = i != -1 && listBox1.Items[i].ToString() != s;
 39 
 40             //上移
 41             btnMoveUp.Enabled = i - 1 >= 0;
 42 
 43             //下移
 44             btnMoveDown.Enabled = i + 1 < listBox1.Items.Count && i != -1; 
 45 
 46             //第一条
 47             btnFirst.Enabled = count > 0 && i != 0;
 48 
 49             //最后一条
 50             btnLast.Enabled = i != count - 1; 
 51 
 52             //上一条
 53             btnPre.Enabled = count > 0 && i != 0 && i != -1;
 54 
 55             //下一条
 56             btnNext.Enabled = i != count - 1 && i != -1;
 57 
 58             //搜索
 59             btnFind.Enabled = textBox1.Text.Trim().Length > 0;
 60 
 61             //模糊搜索
 62             btnFind1.Enabled = btnFind.Enabled;
 63 
 64             //取消选择
 65             btn取消选择.Enabled = i != -1;
 66         }
 67 
 68         private void 添加文本_Click(object sender, EventArgs e)
 69         {
 70             string s = textBox1.Text.Trim();
 71             if (s == "")
 72             {
 73                 MessageBox.Show("内容不能为空或空格", "操作取消", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
 74             }
 75             else
 76             {      
 77                     /*
 78                      * 不添加列表中已经存在的内容， 
 79                      */
 80                 listBox1.Items.Add(s);
 81             }
 82             textBox1.Text = "";
 83             textBox1.Focus();
 84         }
 85 
 86         private void 修改选中的项_Click(object sender, EventArgs e)
 87         {
 88             /*
 89              * 可以通过这样直接修改指定的项的值   listBox1.Items[i] = "指定值";
 90              *   
 91              */
 92             string s = textBox1.Text;
 93             int i = listBox1.SelectedIndex;
 94             if (i != -1)
 95             {
 96                 if (listBox1.Items[i].ToString() != s)
 97                 {
 98                     listBox1.Items[i] = s;
 99                        
100                     s = listBox1.Items[i].ToString();
101                 }
102                 else
103                 {
104                     MessageBox.Show("名字相同", "不用重新命名", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
105                 }
106             }
107         }
108 
109         private void 删除选中的项_Click(object sender, EventArgs e)
110         {
111             /*
112              * 这里的操作是 一次只删除一项
113              */
114             int i = listBox1.SelectedIndex;
115             if (i != -1)
116             {
117                 DialogResult d = MessageBox.Show("是否确定删除该分组？", "删除操作", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
118                 if (d == DialogResult.Yes)
119                 {
120                     listBox1.Items.RemoveAt(i);
121                     textBox1.Text = "";
122 
123                     if (listBox1.Items.Count > 0  )
124                     {
125                         if (i == listBox1.Items.Count)  //这一句是避免抛出异常
126                         {
127                             i = 0;
128                         }
129                         listBox1.SelectedIndex = i;
130                         listBox1.Focus();
131                     }
132                 }
133             }
134         }
135 
136         public static void Swap(ref string a, ref string b)
137         {
138             string c = a;
139             a = b;
140             b = c;
141         }
142 
143         /*
144          *  上移 和下移 实际上是交换2个数值
145          *  上移就是[当前选中]的项和 [上一个项] 对换下值
146          *  下移就是[当前选中]的项和 [下一个项] 对换下值
147          * 
148          */
149 
150         private void btnMoveUp_Click(object sender, EventArgs e)
151         {
152             //[上移]
153             string s = textBox1.Text;
154             int i = listBox1.SelectedIndex;
155             if (i != -1)
156             {
157                 if (i - 1 >= 0)
158                 {
159                     string a = listBox1.Items[i].ToString();
160                     string b = listBox1.Items[i - 1].ToString();
161                     Swap(ref a, ref b);
162                     listBox1.Items[i] = a;
163                     listBox1.Items[i - 1] = b;
164                     listBox1.SelectedIndex = i - 1;
165                 }
166             }
167         }
168 
169         private void btnMoveDown_Click(object sender, EventArgs e)
170         {
171             //[下移]
172             string s = textBox1.Text;
173             int i = listBox1.SelectedIndex;
174             if (i != -1)
175             {
176                 if (i + 1 < listBox1.Items.Count)
177                 {
178                     string a = listBox1.Items[i].ToString();
179                     string b = listBox1.Items[i + 1].ToString();
180                     Swap(ref a, ref b);
181                     listBox1.Items[i] = a;
182                     listBox1.Items[i + 1] = b;
183                     listBox1.SelectedIndex = i + 1;
184                 }
185             }
186         }
187 
188         private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
189         {
190             object obj = listBox1.SelectedItem;
191             string s = obj != null ? obj.ToString() : ""; //listbox如果没有选中则返回null
192             textBox1.Text = s;
193             SetupButtonEnabled();
194         }
195 
196         private void textBox1_TextChanged(object sender, EventArgs e)
197         {
198             //当文本框中的内容和选中的内容一样则不用重命名
199             SetupButtonEnabled();
200         }
201 
202 
203         //用来存放listBox的内容
204         string myStr = "";
205         private void btnSave_Click(object sender, EventArgs e)
206         {
207             /*
208              * 将listBox的值转换成这种格式 aa,bb,cc,ddd,ee,ff 然后写入文件
209              *  ,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
210              */
211             string s = "";
212             StringBuilder sb = new StringBuilder();
213             int length = listBox1.Items.Count;
214             for (int i = 0; i < length; i++)
215             { 
216                 s = listBox1.Items[i].ToString();
217                 sb.Append(s + ",");
218             }
219             s = sb.ToString();
220             if (s.EndsWith(","))
221                 s = s.Substring(0, s.Length - 1);
222             myStr = s;
223             MessageBox.Show(s);
224         }
225 
226         private void btnRead_Click(object sender, EventArgs e)
227         {
228             /*
229              * 读取
230              * 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
231              */
232             string[] arr = myStr.Split(new char[] { ‘,‘ });
233             listBox1.Items.Clear();
234             listBox1.Items.AddRange(arr);
235         }
236 
237         private void listBox1_MouseDown(object sender, MouseEventArgs e)
238         {
239             //双击删除选中的项 
240             int i = listBox1.SelectedIndex;
241             if (i != -1)
242             {
243                 if (e.Clicks == 2)
244                 {
245                     listBox1.Items.RemoveAt(i);
246                 }
247             }
248         }
249 
250         private void 清空_Click(object sender, EventArgs e)
251         {   //清空
252             listBox1.Items.Clear();
253         }
254 
255         private void 第一条_Click(object sender, EventArgs e)
256         {
257             if (listBox1.Items.Count > 0)
258             {
259                 listBox1.SelectedIndex = 0;
260                 label1.Text = listBox1.SelectedItem.ToString();
261             }
262 
263             SetupButtonEnabled();
264         }
265 
266         private void 上一条_Click(object sender, EventArgs e)
267         {
268             if (listBox1.SelectedIndex - 1 >= 0)
269             {
270                 int i = listBox1.SelectedIndex;
271                 i--;
272                 listBox1.SelectedIndex = i;
273 
274                 label1.Text = listBox1.SelectedItem.ToString();
275             }
276             SetupButtonEnabled();
277         }
278 
279         private void 下一条_Click(object sender, EventArgs e)
280         {
281             if (listBox1.SelectedIndex + 1 <= listBox1.Items.Count)
282             {
283                 int i = listBox1.SelectedIndex;
284                 i++;
285                 listBox1.SelectedIndex = i;
286 
287                 label1.Text = listBox1.SelectedItem.ToString();
288             }
289             SetupButtonEnabled();
290         }
291 
292         private void 最后一条_Click(object sender, EventArgs e)
293         {
294             if ( listBox1.Items.Count >0)
295             {
296                 listBox1.SelectedIndex = listBox1.Items.Count - 1;
297                 label1.Text = listBox1.SelectedItem.ToString();
298             }
299             SetupButtonEnabled();
300         }
301 
302         private void 查找内容_Click(object sender, EventArgs e)
303         {
304             /*精确搜索*/
305             string s = textBox1.Text;
306             int i = listBox1.Items.IndexOf(s);   // int i = listBox1.FindStringExact(s);
307             if (i != -1)
308             {
309                 listBox1.SelectedIndex = i;
310             }
311             else
312             {
313                 MessageBox.Show("列表中没有此项");
314             }
315         }
316 
317         private void 模糊查询_Click(object sender, EventArgs e)
318         {
319             //模糊查询  只要项目包含关键字就行
320             string s = textBox1.Text;
321             bool b = false;
322             for (int i = 0; i < listBox1.Items.Count; i++)
323             {
324                 b = false;
325                 string x = listBox1.Items[i].ToString();
326                 if (x.Contains(s))
327                 {
328                     listBox1.SelectedIndex = i;
329                     b = true;
330                     break;
331                 }
332             }
333             if (b == false)
334             {
335                 MessageBox.Show("列表中没有此项");
336             }
337         }
338 
339         private void button1_Click(object sender, EventArgs e)
340         {
341             listBox1.SelectedIndex = -1;
342         }
343     }
344 }