Event 5: My notes…

We are very close to the end of Scripting Games 2013. But before we finish with event 6, time to say few words about event 5… This time I will focus on things I liked, and things I didn’t like, without paying too much attention to category where I’ve seen either.

Continue reading

HashTables to build an object.

You probably know already v2 feature that allows you to pass hashtable to New-Object cmdlet and have key-value pairs changed into property names – values. I love this feature so much that I usually try to write code using it as much as I can. E.g. description of windows.forms.button may look like this:

$button = New-Object Windows.Forms.Button            
$button.Text = 'OK'            
$size = New-Object Drawing.Size            
$size.Height = 200            
$size.Width = 20            
$button.size = $size

And that works fine, but I avoid this type of syntax. My version would look like that:

$Mybutton = New-Object Windows.Forms.Button -Property @{            
    Text = 'OK'            
    Size = New-Object Drawing.Size -Property @{            
        Height = 200            
        Width = 20 }            
    }

Beauty is in an eye of beholder so I won’t convince you mine is better. But I guess it is clear now, that I simply love this v2 way of adding/ defining properties of an object. So when I saw few times question about recursive object creation using hashtables I decided I have to give it a try. So here is my version that creates multi-level PSObject:

function New-ObjectRecursive {            
    param(            
        $Property            
        )            
    if ($Property -is [hashtable]) {             
        $PropertyHash = @{}            
        foreach ($key in $Property.keys) {            
            $PropertyHash.Add($key, $(New-ObjectRecursive $Property[$key]))            
        }            
        New-Object PSObject -Property $PropertyHash            
    } else {            
        $Property            
    }            
}

Now – what I would like to do is somehow ‘inject’ object type. Maybe I will find a way to have something like:

$MyButton = New-ObjectRecurse @{ Type = 'Windows.Forms.Button';            
    Text = 'OK'            
    Size = @{Type = 'Drawing.Size'; Width = 200; Height = 20 }            
    Location = @{ Type = 'Drawing.Point'; X = 10; Y = 10 }            
    }

For now I can only create stuff like that:

$obj = New-ObjectRecursive -Property @{ Alfa = 1; Beta = @{ One = 1; Two = 2; Three = @{ Deep = 'Foo'; Very = 'Sweet' } } }            
$obj.Beta.Three.Deep
Foo

But somebody asked for it, so maybe he has some use case for that… I hope. 😉

So I did it! 🙂

EDIT: soon after I’ve posted I tried to get to the point where I wanted to be. So now you can either give your hashtable a ‘Type’ key to define a type, or skip it and have PSObject (default type):

function New-ObjectRecursive {            
    param(            
        $Property            
        )            
    if ($Property -is [hashtable]) {            
        if ($Type = $Property.Type) {            
            $Property.Remove('Type')            
        } else {            
            $Type = 'PSObject'            
        }            
        $PropertyHash = @{}            
        foreach ($key in $Property.keys) {            
            $PropertyHash.Add($key, $(New-ObjectRecursive $Property[$key]))            
        }            
        New-Object $Type -Property $PropertyHash            
    } else {            
        $Property            
    }            
}            

Enjoy! 😀