自定义错误类型和错误信息的实例

这里定义了一个错误的激发条件 (month < 1 Or month > 12) ，     然后用Throw New ArgumentOutOfRangeException()抛出一个异常，再通过Try中的 Catch e As ArgumentOutOfRangeException接收异常提示并做出反应。

代码如下：

 

Module Module1

    Sub Main()
        Dim month As Integer
        Do While (True)
            Try
                KeyinMonth(month)
                Exit Do
            Catch e As ArgumentOutOfRangeException
                Console.WriteLine("乐博网提示：不合理月份")
            Catch e As Exception
                Console.WriteLine("乐博网提示：其它种错误")
            End Try
        Loop
        Console.ReadLine()
    End Sub

    Public Sub KeyinMonth(ByRef month As Integer)
        Console.Write("乐博网提示：输入月份 ( 1 - 12 ) : ")
        month = Console.ReadLine()
        If (month < 1 Or month > 12) Then
            Throw New ArgumentOutOfRangeException()
        End If
    End Sub

End Module