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求解释解决办法

发布时间: 2012-04-23 13:17:38 作者: rapoo

求解释
我在编写一个计算器的时候为什么必须这样写
dim x as integer
dim y as integer
dim s as integer
Private Sub btnjia_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnjia.Click
x= val(text1.text)
y = val (text2. text)
s=x+y
text3.text=s
end sub
为什么写成这样就出错啊
dim x as integer = val(text1.text)
dim y as integer = val(text2.text)
dim s as integer
Private Sub btnjia_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnjia.Click
s=x+y
text3.text = s
end sub
还有怎样让text3显示的为text1.text+text2.text=text3.text

[解决办法]
dim x as integer = val(text1.text)
你这样,text1还没有输入内容你就开始使用Text了
[解决办法]

VB.NET code
  Private Sub btnjia_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnjia.Click  '下面这三行变量定义要是搬到方法体里面就不会错了,也就是说在方法体外面的时候属于模块变量,  '组件 text1, text2 的 TEXT 属性都还没有被赋值;你后面再输入的值不会改变 x 和 y 最初所  '得到的值;  dim x as integer = val(text1.text)  dim y as integer = val(text2.text)  dim s as integer  s=x+y  text3.text = send sub 

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