How to iterate through an array of objects in Powershell

Question

I'm doing some basic validation on form fields. What's the correct way to iterate through an array of objects to validate them? When I try the below I get

The property 'BackColor' cannot be found on this object. Verify that the property exists and can be set.

I guess what I'm missing is a way of telling Powershell these are references to other variables, rather than variables themselves.

$MandatoryFields = @(
    'txtUsername',
    'txtFirst',
    'txtLast',
    'txtEmail',
    'ComboLicense'
)

ForEach ($Field in $MandatoryFields) {
    If ([string]::IsNullOrWhitespace($Field.text)) {
        $Validation = "failed"
        $Field.BackColor = "red"
    }
}

EDIT: Okay, what I needed was the actual variables in the array, like so:

$MandatoryFields = @(
    $txtUsername,
    $txtFirst,
    $txtLast,
    $txtEmail,
    $ComboLicense
)

Not sure,I understand,but,does this help https://stackoverflow.com/questions/37688708/iterate-over-psobject-properties-in-powershell — TheGameiswar, Mar 08 '21 at 11:21
Don't think so. So in my example, I have objects in the script - txtUsername, txtFirst etc - I've written down the names of those objects in the $MandatoryFields array. And I want to do this with each of those objects in a ForEach loop. I want to do those things with the actual objects, not with the names of those objects that I've written in the $MandatoryFields array. Does that make sense? — daninthemix, Mar 08 '21 at 11:26
In other words, I need to tell Powershell - don't worry about the text 'txtUsername' in this array - instead go and look at the actual txtUsername object elsewhere in this script and give me a property... — daninthemix, Mar 08 '21 at 11:27
what are you trying to do with those objects,can you give more context of this ? — TheGameiswar, Mar 08 '21 at 11:30
Basically I want to read the Text property of a bunch of objects, check that its not empty, and if it is, change the BackColor property of that object to red. I wanted to do it with an array of Object names, rather than having dozens of IF statements. — daninthemix, Mar 08 '21 at 11:37
Take a look at my post https://stackoverflow.com/questions/66106458/foreach-printing-out-whole-array . Kind of similar, ignore the actual question and see the code. — Abraham Zinala, Mar 08 '21 at 14:01

TheGameiswar · Answer 1 · 2021-03-08T13:22:04.877

2

Try adding your objects to an array like below

$objects = [System.Collections.ArrayList]@()

$myObject = [PSCustomObject]@{
    Name     = 'Kevin'
    Language = 'PowerShell'
    State    = 'Texas'
}


$objects.add($myObject)

$myObject1= [PSCustomObject]@{
    Name     = 'Kevin'
    Language = 'PowerShell'
    State    = 'Texas'
}


  $objects.add($myObject1)

foreach($obj in $objects){

$obj.firstname

}

edited Mar 08 '21 at 13:22

answered Mar 08 '21 at 11:48

TheGameiswar

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Arrays are not expandable so probably better in this case to use something like an ArrayList, or List[object], no? Otherwise you are processing an entire new array every time you call += – Efie Mar 08 '21 at 13:19

score 0 · Answer 2 · answered Mar 08 '21 at 12:06

I'm assuming your using System.Windows.Forms to create your form. If that's the case when adding controls you should assign a name to the control. Then you can loop through your controls and check if the control name matches your list of mandatory controls and then execute your check.

$MandatoryFields = @(
    'txtUsername',
    'txtFirst',
    'txtLast',
    'txtEmail',
    'ComboLicense'
)

$Controls = MyForm.controls

ForEach ($c in $Controls) {
    ForEach ($Field in $MandatoryFields) {
        if ($c.Name -eq $Field) {
            If ([string]::IsNullOrWhitespace($c.text)) {
                $Validation = "failed"
                $c.BackColor = "red"
            }
        }
    }
}

How to iterate through an array of objects in Powershell

2 Answers2