Powershell How to Overload Array Index Operator?

问题

In Powershell, how do you overload the indexing of an array operator?

Here is what I am doing now:

class ThreeArray {

    $myArray = @(1, 2, 3)

    [int] getValue ($index) {
        return $this.myArray[$index]
    }

    setValue ($index, $value) {
        $this.myArray[$index] = $value
    }
}

$myThreeArray = New-Object ThreeArray

Write-Host $myThreeArray.getValue(1) # 2

$myThreeArray.setValue(2, 5)
Write-Host $myThreeArray.getValue(2) # 5

And, I want to do this:

$myThreeArray = New-Object ThreeArray

Write-Host $myThreeArray[1] # 2

$myThreeArray[2] = 5
Write-Host $myThreeArray[2] # 5

So, how do I operator overload the indexing of an array? Is it even possible at all?

Thanks!

回答1:

The simplest approach is to derive from System.Collections.ObjectModel.Collection<T>

class ThreeArray : System.Collections.ObjectModel.Collection[string]
{
  ThreeArray() : base([System.Collections.Generic.List[string]](1, 2, 3)) {}
}

To demonstrate:

$myThreeArray = [ThreeArray]::new() # same as: New-Object ThreeArray

$myThreeArray[1]     # print the 2nd element

$myThreeArray[2] = 5 # modify the 3rd element...
$myThreeArray[2]     # and print it

'--- all elements:'
$myThreeArray        # print all elmements

The above yields: