Question

VB.NET如何把字符串（不全是数字或为空）转换成数字？

编一个类似于注册机的程序，怎么把TextBox里带字母的字符串转换成数字？（转换成编码也行，只要能计算）
这样写如果不输入或输入的不是纯数字就报错：
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
'两个TextBox已建立，TextBox1用于输入用户名，TextBox2用于显示注册码
Dim usernane, pasward As String
Dim temp As Long
usernane = CLng(TextBox1.Text)
temp = usernane * 3 - 500
pasward = CStr(temp)
TextBox2.Text = pasward
End Sub

Answer 1

明白你的意思了,只要是字母都会转换成数字,帮你写好了("usernane"和 "pasward" 我这里写成 "username" 和" password"）
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim username, password As String
Dim temp As Long
Dim r As String = ""
Dim v As String = TextBox1.Text
For Each c In v.ToString
If IsNumeric(c) Then
r &= c
Else
r &= ((Asc(c) - 65).ToString("00"))
End If
Next
username = r
temp = username * 3 - 500
password = CStr(temp)
TextBox2.Text = password
End Sub

Answer 2

解决的思路：
方法1：把其中非数字忽略掉，即去除。
方法2：把字符转换成它的ASCII码.
另外，你的代码中声明变量的语句：Dim usernane, pasward As String
把usernane声明为String类型了，怎么在使用的时候：usernane = CLng(TextBox1.Text)
是试图存放长整型的数值呢？

Answer 3

明白你的意思了,只要是字母都会转换成数字,帮你写好了("usernane"和 "pasward" 我这里写成 "username" 和" password"）
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim username, password As String
Dim temp As Long
Dim r As String = ""
Dim v As String = TextBox1.Text
For Each c In v.ToString
If IsNumeric(c) Then
r &= c
Else
r &= ((Asc(c) - 65).ToString("00"))
End If
Next
username = r
temp = username * 3 - 500
password = CStr(temp)
TextBox2.Text = password
End Sub