winform文本框只能输入数字

.net(c#) winform文本框只能输入数字,不能其他非法字符 C#的winform中控制TextBox中只能输入数字（加上固定位数和首位不能为0)(KeyPress事件) 给个最简单的方法： private void textBox3_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e) {     //阻止从键盘输入键     e.Handled = true;     if(e.KeyChar>='0' && e.KeyChar <='9')     {         e.Handled = false;     } //支持退格Backspace键 if (e.KeyChar == (char)0x08) { e.Handled = false; } } 或者 private void tbID_KeyPress(object sender, KeyPressEventArgs e)         {             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             {                 e.Handled = true;             }         } 多条件的： private void TxtUser_KeyPress(object sender, KeyPressEventArgs e)         {             //阻止从键盘输入键            e.Handled = true;             if ((e.KeyChar >= '0' && e.KeyChar <= '9') || (e.KeyChar == (char)8))             {                 if ((e.KeyChar == (char)8)) { e.Handled = false; return; }                 else                 {                     int len = TxtUser.Text.Length;                     if (len < 5)                     {                         if (len == 0 && e.KeyChar != '0')                         {                             e.Handled = false; return;                         }                         else if(len == 0)                         {                             MessageBox.Show("编号不能以0开头！"); return;                         }                         e.Handled = false; return;                     }                     else                     {                         MessageBox.Show("编号最多只能输入5位数字！");                     }                 }             }             else             {                 MessageBox.Show("编号只能输入数字！");             }                     }