This PowerShell script creates a hierarchical list of objects with DisplayName, ID, and ParentID properties, organized into three levels. It also builds a HashTable to store these objects and calculates a FullPath property for each object by recursively resolving the hierarchy using the ParentID. The FullPath represents the hierarchical path fro…

FullPathHashtable.ps1

# Define the list of objects
$objects = @(
    # Level 1
    [PSCustomObject]@{ DisplayName = "Root1"; ID = 1; ParentID = $null }
    [PSCustomObject]@{ DisplayName = "Root2"; ID = 2; ParentID = $null }

    # Level 2
    [PSCustomObject]@{ DisplayName = "Child1.1"; ID = 3; ParentID = 1 }
    [PSCustomObject]@{ DisplayName = "Child1.2"; ID = 4; ParentID = 1 }
    [PSCustomObject]@{ DisplayName = "Child2.1"; ID = 5; ParentID = 2 }
    [PSCustomObject]@{ DisplayName = "Child2.2"; ID = 6; ParentID = 2 }

    # Level 3
    [PSCustomObject]@{ DisplayName = "GrandChild1.1.1"; ID = 7; ParentID = 3 }
    [PSCustomObject]@{ DisplayName = "GrandChild1.1.2"; ID = 8; ParentID = 3 }
    [PSCustomObject]@{ DisplayName = "GrandChild1.2.1"; ID = 9; ParentID = 4 }
    [PSCustomObject]@{ DisplayName = "GrandChild2.1.1"; ID = 10; ParentID = 5 }
    [PSCustomObject]@{ DisplayName = "GrandChild2.1.2"; ID = 11; ParentID = 5 }
    [PSCustomObject]@{ DisplayName = "GrandChild2.2.1"; ID = 12; ParentID = 6 }

    # Additional objects to make 15 total
    [PSCustomObject]@{ DisplayName = "Child1.3"; ID = 13; ParentID = 1 }
    [PSCustomObject]@{ DisplayName = "GrandChild1.3.1"; ID = 14; ParentID = 13 }
    [PSCustomObject]@{ DisplayName = "GrandChild1.3.2"; ID = 15; ParentID = 13 }
)

# Create a HashTable to store the objects
$ObjectsHashTable = @{}
$Objects |ForEach-Object { $ObjectsHashTable[$_.ID] = $_ }

# Add a script property that looks up it's own parent via the table
$Objects |Add-Member -MemberType ScriptProperty -Name FullPath -Value {
  @(
    if ($this.ParentID -and $ObjectsHashTable.Contains($this.ParentID)){
      $ObjectsHashTable[$this.ParentID].FullPath
    }
    $this.DisplayName
  ) -join '\'
} -SecondValue { throw [InvalidOperationException]::new('Hands off!') } -Force -PassThru