PowerShell–Object Orientation

PowerShell does not have a class construct as a first class citizen. You can create objects either from .NET or creating CmdLets but how do you create an object from a pure PowerShell script?.

I came up with a solution previously I would like to share. However doing a bit of searching afterwards I found this project on CodePlex The solution looks pretty awesome so it is probably worth checking out as well.

The solution I came up with previously was to use PSObject and using Add-Member Cmdlet.

I wanted to be able to describe the function that I will be using as follows:

PowerShell Object Builder Definition

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function New-ObjectBuilder() { }

You would use this as follows:

PowerShell Object Builder Usage

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function New-MyObject() {        $obj = New-ObjectBuilder     $obj.AddBackingField("_Test", "testing")     $obj.AddProperty("Test", [ref]$obj._Test)     $obj.AddMethod("TestRun", {         param ($aaa, $bbb)         Write-Host "TestRun: " $this.Test, $aaa, $bbb        });     return $obj } $obj = New-MyObject $obj.TestRun("a1", "b11")

And there is not really that much code to implement this function:

PowerShell Object Builder

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function New-ObjectBuilder() {     $instance = new-object PSObject           $instance | add-member -MemberType ScriptMethod -Name AddProperty -Value {         param ($name, [ref]$backingField)         $this | add-member -MemberType ScriptProperty -Name $name -Value {             return $backingField.Value         }.GetNewClosure() -SecondValue {             $backingField.Value = $args[0]         }.GetNewClosure()       }           $instance | add-member -MemberType ScriptMethod -Name AddBackingField -Value {         param ($name, $value = '')         $this = Add-Member -InputObject $this -MemberType NoteProperty -Name $name -Value $value -PassThru     }       $instance | add-member -MemberType ScriptMethod -Name AddMethod -Value {         param ($name, $codeBlock)         $this | add-member -MemberType ScriptMethod -Name $name -Value $codeBlock     }           return $instance }

You can now reuse this function and create new functions to construct your object