验证以确保输入的值是整数

Question

我想要一个验证方法来确保输入的值是有效的，它必须是一个整数（可以包括负数）并且不能为空。我已经写了这段代码，但是不正确，请有人帮助我。谢谢

If (b <> Integer Or " ") Then
            Console.WriteLine("Value entered must be a number")
        End If


new code:
Line98:
        Console.WriteLine("Please input the value of, B:")
        b = Console.ReadLine()
        If Not Integer.TryParse(b, New Integer) Then
            Console.WriteLine("Value entered must be a number")
            GoTo Line98
        End If

所以我使用了一个 select 语句，如果用户输入“abckak”任何非数字数据，我会收到错误 Unhandled Exception: System.InvalidCastException: Conversion from string “gakjdg” to type 'Integer' is not valid.

如何解决这个问题，这是我的代码的一个简单示例

 Console.WriteLine("..........Main Menu..........")
            Console.WriteLine("Please input 1 ")
            Console.WriteLine("Please input 2")
            Console.WriteLine("Please input 3 ")
            Console.WriteLine("Please input 4 ")
            Console.WriteLine("Please input 5 for Help")
            Console.WriteLine("Please input 6 to Exit")

            Console.WriteLine("Please enter your choice: ")

            Choice = Console.ReadLine()
            Select Case Choice

case1; etc

Case Else
                    Console.WriteLine("Error: " & Choice & " is not a option, Please try again")

Answer 1

查看Integer.TryParse，如果可以，它会尝试将字符串解析为整数，如果不能它不会抛出异常...

 Dim b As Integer
 Console.WriteLine("Please input the value of, B:")            
 If Not Integer.TryParse(Console.ReadLine(), b) Then
    Console.WriteLine("Value entered must be a number")
    GoTo Line98
 End If

如果它可以解析用户的输入，那么b就是解析出来的值，否则b的值仍然是0...

按评论编辑

Dim b As Integer
Do Until b > 0
    Console.WriteLine("Please input the value of, B:")            
    If Not Integer.TryParse(Console.ReadLine(), b) OrElse b <= 0 Then
      Console.WriteLine("Value entered must be a number and not equal 0")
      GoTo Line98
    End If
 Loop