vb.net – 如何使用Try,Catch和Finally

我的任务是编写一个程序,询问用户10个数字,然后找到它的平均值,并且必须包括Try,Catch和Finally关键字. (除以零例外).

如何使用Try,Catch和Finally？

到目前为止我的程序看起来像这样：

Module Module1
    Public Sub Main()
            Dim A,B,C,D,E,F,G,H,I,J,K,L,M As Integer
            Console.WriteLine("Enter 1st Number: ")
            A = Console.ReadLine()
            Console.WriteLine("Enter 2nd Number: ")
            B = Console.ReadLine()
            Console.WriteLine("Enter 3rd Number: ")
            C = Console.ReadLine()
            Console.WriteLine("Enter 4th Number: ")
            D = Console.ReadLine()
            Console.WriteLine("Enter 5th Number: ")
            E = Console.ReadLine()
            Console.WriteLine("Enter 6th Number: ")
            F = Console.ReadLine()
            Console.WriteLine("Enter 7th Number: ")
            G = Console.ReadLine()
            Console.WriteLine("Enter 8th Number: ")
            H = Console.ReadLine()
            Console.WriteLine("Enter 9th Number: ")
            I = Console.ReadLine()
            Console.WriteLine("Enter 10th Number: ")
            J = Console.ReadLine()
            K = (A+B+C+D+E+F+G+H+I+J)
            Console.WriteLine("Enter the amount of numbers to average: ")
            M = Console.ReadLine()
            L = K / M
            Console.WriteLine("The Average Is: " & L)
            Console.ReadKey()
    End Sub
End Module

Try,Catch,Finally块对于处理错误非常有用,在正常情况下它会导致程序崩溃.

例如：

Dim n As Integer
Dim a As Integer = 0
Dim b As Integer = 1
Try
    n = b / a
Catch
    MsgBox("We've crashed :(")
Finally
    MsgBox("..but we're still alive!")
End Try

您还可以获得有关确切错误的信息,可能的用途是您可能希望将其过滤掉,以便忽略特定错误,例如：

Dim n As Integer
Dim a As Integer = 0
Dim b As Integer = 1
Try
    n = a / b
Catch ex As DivideByZeroException
    MsgBox("We've crashed,here's the specific error: " + ex.Message)
Catch ex As Exception
    MsgBox("Some other error happened: " + ex.Message)
Finally
    MsgBox("..but we're still alive!")
End Try

这三部分：

>尝试：尝试执行此块中的代码,如果失败;
> Catch：捕获异常/错误并执行此块内的代码
>最后：最后在此块中执行代码,无论Try和Catch组件中发生了什么.

例如,您可以针对特定用例使用类似的内容：

[...]
Try
    L = K / M
    Console.WriteLine("The Average Is: " & L)
    Console.ReadKey()
Catch
    Console.WriteLine("Uh oh,we've divided by 0!")
Finally
    Console.WriteLine("Press any key to continue.")
    [...]
End Try

official documentation有一些方便的信息.

作为对您的问题发表评论的用户(Mark),您的代码存在其他问题(不会覆盖它们,因为它超出了问题的范围),您应该turn on Option Strict查看它们.利用For循环和数组或列表,您的代码也可以更高效,但我会留给您做.