private void textBox1_KeyPress(object sender,KeyPressEventArgs e)  
{  
      //数字0~9所对应的keychar为48~57
      e.Handled = true;  
      //输入0-9
      if ((e.KeyChar >= 47 && e.KeyChar <= 58))  
      {  
            e.Handled = false;  
       }  
}