此方法控制TextBox只收数字：0~9 , 也自可以定义其它可输入字符,如改成: 65~123,只允许输入: a~z和A~Z 等.-This method controls TextBox only accept numbers: 0 to 9, but also from other available input character can be defined, such as changed: 65 ~ 123, only allows the input: a ~ z and A ~ Z and so on.