PowerShell 技能连载 - 验证变量有效性

变量和函数参数可以通过验证属性自动地验证有效性。以下是一个简单的例子，确保 $test1 只能存储 1-10 之间的值：

[ValidateRange(1,10)]$test1 = 10

当您将一个小于 1 或大于 10 的值赋给这个变量，PowerShell 将会抛出一个异常。不过通过这种方式您无法控制异常的问本。

通过使用脚本验证器，您可以选择自己希望的错误信息：

[ValidateScript({
If ($_ -gt 10)
{ throw 'You have submitted a value greater than 10. That will not work, dummy!' }
Elseif ($_ -lt 1)
{ throw 'You have submitted a value lower than 1. That will not work, dummy!' }

$true
})]$test2 = 10

以下是输出结果：

PS C:\> $test2 =  4

PS C:\> $test2 =  11
You have submitted a  value greater than 10. That will  not work, dummy!
At line:5 char:3
+ { throw 'You have submitted  a value greater than 10. That will not work, dummy ...
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : OperationStopped: (You have submitted  a...not work, dummy!:String
    ) [], RuntimeException
    + FullyQualifiedErrorId : You have submitted  a value greater than 10. That  will not work, dummy!



PS C:\> $test2 =  -2
You have submitted a  value lower than 1. That will  not work, dummy!
At line:7 char:3
+ { throw 'You have submitted  a value lower than 1. That will not work, dummy ...
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : OperationStopped: (You have submitted  a...not work, dummy!:String
    ) [], RuntimeException
    + FullyQualifiedErrorId : You have  submitted a value lower than 1. That  will not work, dummy!