How to Create [PsCustomObject] with Properties AND Methods

Question

I try to define an object with custom methods like this but my syntaxe is wrong:

$Obj = [pscustomobject]@{
    A = @(5,6,7)
    B = 9
    Len_A = {return $this.A.count;}
    Sum_A = {return (SumOf $this.A);}
}

for use like :

$Obj.Len_A()       # return 3
$Obj.A += @(8,9)   # @(5,6,7,8,9)
$Obj.Len_A()       # return 5

Answer 1

You probably want to use the Add-Member cmdlet:

$Obj = [pscustomobject]@{
    A = @(5,6,7)
    B = 9
}

$Obj | Add-Member -MemberType ScriptMethod -Name "Len_A" -Force -Value {
    $this.A.count 
} 

Now you can call the method as expected using:

$Obj.Len_A()

Answer 2

You did not mention which version of powershell you are using. If you want object-orientation use class like this.

class CustomClass {
     $A = @(5,6,7)
     $B = 9
     [int] Len_A(){return $this.A.Count}
     [int] Sum_A(){
       $sum = 0
       $this.A | ForEach-Object {$sum += $_}
      return $sum
     }
}

$c = New-Object CustomClass
$s = $c.Sum_A()
$l = $c.Len_A()