Convert argb to string

Question

Which method allows convert ARGB to string as 'int, int, int'? Example. The $Main background color is set as a string '0, 100, 200'. Return $Main.BackColor gives ARGB but not string '0, 100, 200':

$Main  = [System.Windows.Forms.Form] @{
    BackColor = '0, 100, 200'
}

$Main.BackColor
--------------
R             : 0
G             : 100
B             : 200
A             : 255
IsKnownColor  : False
IsEmpty       : False
IsNamedColor  : False
IsSystemColor : False
Name          : ff0064c8

The To.String() method returns the result Color [A=255, R=0, G=100, B=200] . This is not what is expected.

At the moment I am doing this:

 ('R', 'G', 'B').ForEach({ $Main.BackColor.$_ }) -join ', '

--------------
0, 100, 200

However, I hope that there are special methods for converting as ARGB to string, as string to ARGB. What are these methods? Thanks

Answer 1

However, I hope that there are special methods for converting as argb to string, as string to argb. What are these methods?

You'd think so, but to my knowledge there isn't a builtin two-way convertion for this, unfortunately.

Here are a couple of things you can do instead:

Create your own ConvertFrom-Color function:

function ConvertFrom-Color
{
    param(
        [Parameter(Mandatory=$true,ValueFromPipeline=$true)]
        [System.Drawing.Color[]]$InputColor
    )

    process {
        foreach($color in $InputColor){
            $color.R,$color.G,$color.B -join ', '
        }
    }
}

And use when needed:

PS C:\> $colorString = $Main.BackColor |ConvertFrom-Color
PS C:\> $colorString
0, 100, 200

---

Use an [int]

An ARGB color consists of 4 1-byte channels, which fits perfectly into a 32-bit integer. If you need to communicate a distinct color using a single argument, this is already supported:

PS C:\> $color = [System.Drawing.Color]'0,100,100'
PS C:\> $color.ToArgb()
-16751516
PS C:\> $argbValue = $color.ToArgb()
PS C:\> [System.Drawing.Color]::FromArgb($argbValue)

R             : 0
G             : 100
B             : 100
A             : 255
IsKnownColor  : False
IsEmpty       : False
IsNamedColor  : False
IsSystemColor : False
Name          : ff006464

Just like with your initial string representation, it's worth highlighting that converting from the [int] representation works both with explicit casts and implicit conversions when assigning to typed properties:

$argbValue = -16751516
# This works just fine
[System.Drawing.Color]$argbValue
# As does this
[System.Windows.Forms.Form]@{ BackColor = $argbValue }

---

Override Color.ToString()

Since you're interested in changing the behavior of the default string representation of System.Drawing.Color, you might as well override the ToString() method implementation:

Update-TypeData -TypeName System.Drawing.Color -MemberType ScriptMethod -MemberName ToString -Value {
    $this.psobject.Properties['R','G','B'].Value -join ', '
} -Force

Now all instances of [System.Drawing.Color] will use your custom ToString() method when converted to a string:

PS C:\> "$($Main.BackColor)"
0, 100, 200

Answer 2

There are some nice and initiative answers for this question, but it looks like all have overlooked the correct way, using type converters. There is a ColorConverter responsible for ConvertTo and ConvertFrom String/Color:

$Color = [System.Drawing.Color]'0, 100, 200'
[System.Drawing.ColorConverter]::new().ConvertToString($Color)
# Result: 0, 100, 200

This is the same class which is used by PropertyGrid to convert the string to Color or Color and vice versa.

It will take care of A element of the color as well, for example if you create the color like 100, 0, 100, 200. This solution automatically include or ignore A portion whenever is required:

$Color = [System.Drawing.Color]'100, 0, 100, 200'
[System.Drawing.ColorConverter]::new().ConvertToString($Color)
# Result: 100, 0, 100, 200