private void textBox1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
if(((e.KeyChar >= 'A')&&(e.KeyChar <='Z'))||((e.KeyChar >= '0')&&(e.KeyChar <= '9'))||(e.KeyChar == 8)||((e.KeyChar >='a')&&(e.KeyChar<='z')))
{
//
}
else
{
e.Handled = true;
}
}