1 private void textBox3_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
2 {
3 //阻止从键盘输入键
4 e.Handled = true;
5 if(e.KeyChar>='0' && e.KeyChar <='9')
6 {
7 e.Handled = false;
8 }
9
10 }
11 或者
12 private void tbID_KeyPress(object sender, KeyPressEventArgs e)
13 {
14 if (!((e.KeyChar >= '0' && e.KeyChar <= '9') || e.KeyChar == ' '))//不输入输入除了数字之外的所有非法字符的判断
15 {
16 e.Handled = true;
17 }
18 }
19
20
21 多条件的：
22
23 private void TxtUser_KeyPress(object sender, KeyPressEventArgs e)
24 {
25 //阻止从键盘输入键
26 e.Handled = true;
27
28 if ((e.KeyChar >= '0' && e.KeyChar <= '9') || (e.KeyChar == (char)8))
29 {
30
31 if ((e.KeyChar == (char)8)) { e.Handled = false; return; }
32 else
33 {
34 int len = TxtUser.Text.Length;
35 if (len < 5)
36 {
37 if (len == 0 && e.KeyChar != '0')
38 {
39 e.Handled = false; return;
40 }
41 else if(len == 0)
42 {
43 MessageBox.Show("编号不能以0开头！"); return;
44 }
45 e.Handled = false; return;
46 }
47 else
48 {
49 MessageBox.Show("编号最多只能输入5位数字！");
50 }
51 }
52 }
53 else
54 {
55 MessageBox.Show("编号只能输入数字！");
56 }
57
58
59 }
