Showing error while adding element in List[int] in powershell? - powershell

Question

$sumList= New-Object System.Collections.Generic.List[int]
$eventList = New-Object System.Collections.Generic.List[string]
$preSumList= New-Object System.Collections.Generic.List[int]
$threadInitDelay = [int]$commaSplit[++$eventIndex].Split(':')[1].Trim()
$preProcessTime = [int]$commaSplit[++$eventIndex].Split(':')[1].Trim()+[int]$commaSplit[++$eventIndex].Split(':')[1].Trim()+$commaSplit[[int]++$eventIndex].Split(':')[1].Trim()
$respTime = [int]$commaSplit[++$eventIndex].Split(':')[1].Trim();
$index =$eventList.FindIndex({param([string]$s) return $s -like 'hi'})
if($index -eq -1){
$eventList.Add($eventName)
$sumList.Add($threadInitDelay)
$respSumList.Add($respTime)
Getting this error:
Method invocation failed because [System.Int32[]] doesn't contain a method named 'Add'.
At D:\Powercel\PowershellPractice.ps1:151 char:19
+ $sumList.Add <<<< ($threadInitDelay)
+ CategoryInfo : InvalidOperation: (Add:String) [], RuntimeException
+ FullyQualifiedErrorId : MethodNotFound
Method invocation failed because [System.Int32[]] doesn't contain a method named 'Add'.
At D:\Powercel\PowershellPractice.ps1:152 char:23
+ $respSumList.Add <<<< ($respTime)
+ CategoryInfo : InvalidOperation: (Add:String) [], RuntimeException
+ FullyQualifiedErrorId : MethodNotFound
Method invocation failed because [System.Int32[]] doesn't contain a method named 'Add'.
At D:\Powercel\PowershellPractice.ps1:153 char:23
+ $respMaxTime.Add <<<< ($respTime)
+ CategoryInfo : InvalidOperation: (Add:String) [], RuntimeException
+ FullyQualifiedErrorId : MethodNotFound
Method invocation failed because [System.Int32[]] doesn't contain a method named 'Add'.
At D:\Powercel\PowershellPractice.ps1:155 char:19
+ $minTime.Add <<<< ($threadInitDelay)
+ CategoryInfo : InvalidOperation: (Add:String) [], RuntimeException
+ FullyQualifiedErrorId : MethodNotFound
Could you please help me out?

Answer 1

A possible scenario is that you were testing and actually casted those variables like the error states. The error is not wrong. Those variables are not the list types that you have in your code. I can almost reproduce this issue:
PS M:\Scripts\Inno\Output> [int[]]$sumlist = 5,5
PS M:\Scripts\Inno\Output> $sumlist.GetType().Fullname
System.Int32[]
PS M:\Scripts\Inno\Output> $sumlist.Add(5)
Exception calling "Add" with "1" argument(s): "Collection was of a fixed size."
At line:1 char:1
+ $sumlist.Add(5)
+ ~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : NotSupportedException
PS M:\Scripts\Inno\Output> $sumlist = New-Object System.Collections.Generic.List[int]
While I didn't get the same error as you the point is the type of the variable didn't change even though I tried to recasted it. That is because of property of the variable explained in this answer by PetSerAl. Have a look at the command Get-Variable sumlist | ft Name,Attributes and you should see System.Management.Automation.ArgumentTypeConverterAttribute. Removing the variable and starting again I get your expected behavior.
PS M:\Scripts\Inno\Output> Remove-Variable sumlist
PS M:\Scripts\Inno\Output> $sumlist = New-Object System.Collections.Generic.List[int]
PS M:\Scripts\Inno\Output> $sumlist.Add(5)
PS M:\Scripts\Inno\Output> $sumlist.GetType().FullName
System.Collections.Generic.List`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]