使用正则表达式限制TextBox输入

 1     /// <summary>

 2     ///  使用正则表达式限制输入

 3     /// </summary>

 4     public class TextBoxRegex : TextBox

 5     {

 6         // 正则表达式，只含有汉字、数字、字母、下划线不能以数字开头 

 7         private const string NamimgPattern = "^(?![0-9])[a-zA-Z0-9_\u4e00-\u9fa5]{1,30}$";

 8 

 9         public TextBoxRegex()

10         {

11             TextChanged += TextBoxRegex_TextChanged;

12         }

13 

14         private void TextBoxRegex_TextChanged(object sender, TextChangedEventArgs e)

15         {

16             //屏蔽非法字符粘贴

17             var textBox = sender as TextBox;

18             if (textBox != null)

19             {

20                 var change = new TextChange[e.Changes.Count];

21                 e.Changes.CopyTo(change, 0);

22 

23                 int offset = change[0].Offset;

24                 if (change[0].AddedLength > 0)

25                 {

26                     if (!Regex.IsMatch(textBox.Text, NamimgPattern, RegexOptions.IgnoreCase))

27                     {

28                         // 不符合正则表达式时移除内容，设置光标位置

29                         textBox.Text = textBox.Text.Remove(offset, change[0].AddedLength);

30                         textBox.Select(offset, 0);

31                     }

32                 }

33             }

34         }

35     }