New in PowerShell 6 - Positive And Negative Parameter Validation
source link: https://thomasrayner.ca/new-in-powershell-6-positive-and-negative-parameter-validation/
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New in PowerShell 6 - Positive And Negative Parameter Validation
If you’ve written at least a couple of advanced PowerShell functions, you’re probably no stranger to parameter validation. These are the attributes you attach to parameters to make sure that they match a certain regular expression using [ValidatePattern()], or that when they are plugged into a certain script, that it evaluates to true using [ValidateScript({})]. You’ve probably also used [ValidateRange()] to make sure a number falls between a min and a max value that you specified.
In PowerShell 6, though, there’s something new and cool you can do with ValidateRange. You can specify in a convenient new syntax that the value must be positive or negative.
To do this, you start with a normal ValidateRange attribute, and instead of providing a range of numbers, you just use the word “Positive” or “Negative”, like this.
[ValidateRange('Positive')]$int = 10
[ValidateRange('Negative')]$int = -10
These will both work correctly because we’re assigning a value that works with the validation we’ve specified. Here’s two that will throw errors.
[ValidateRange('Positive')]$int = -10
[ValidateRange('Negative')]$int = 10
Here’s what it looks like in the console.
Neat, right?
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