Debugger cannot find [System.Drawing.Color] when in script

[gerane]

When debugging a script that contains a Color type it throws an error.

Example is using New-SlackMessageAttachment -Color $([System.Drawing.Color]::red)

Unable to find type [System.Drawing.Color].
+ New-SlackMessageAttachment -Color $([System.Drawing.Color]::red) `
+                                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (System.Drawing.Color:TypeName) [], RuntimeException
    + FullyQualifiedErrorId : TypeNotFound

Unable to find type [System.Drawing.Color].
+ ... SlackMessageAttachment -Color $([System.Drawing.Color]::LightGreen) `
+                                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (System.Drawing.Color:TypeName) [], RuntimeException
    + FullyQualifiedErrorId : TypeNotFound

[rkeithhill]

You need to load that assembly Add-Type -Assembly System.Drawing

[gerane]

Why does the debugger need to load it? Running in any other context does not require it to be loaded.

[rkeithhill]

Well, if I fire up a PowerShell v5 console with -NoProfile it doesn't have the assembly loaded either:

PS C:\Users\Keith> [System.Drawing.Color]::LightGreen
Unable to find type [System.Drawing.Color].
At line:1 char:1
+ [System.Drawing.Color]::LightGreen
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (System.Drawing.Color:TypeName) [], RuntimeException
    + FullyQualifiedErrorId : TypeNotFound

However, once I execute Out-GridView that assembly is loaded. It would also be loaded by default for ISE since ISE is a WPF app.

I wouldn't rely on PowerShell loading an assembly meant for GUI apps. For instance, you could get the debugger to work by simply calling this command before referencing the color:

Microsoft.PowerShell.Management\Get-Clipboard | Out-Null

That command pulls in WinForms, which pulls in System.Drawing. IMO it is better to explicitly add the assembly.

[daviwil]

Yep, that assembly is not loaded by default. Keith is correct, it gets loaded when anything UI-related gets loaded into the PowerShell session. Out-GridView is one way, running your code in the ISE is another way. If the Slack module depends on that type it needs to call Add-Type -Assembly System.Drawing when the module gets loaded.

If you start powershell.exe with -NoProfile and try to run that command, does it work?

[gerane]

This isn't actually a GUI app, but is sending a slack message. The color was for the color of the notification. I will just have to add the type before hand.

[rkeithhill]

It doesn't have to be a GUI app. I have PSReadline handler function loaded in my profile that loads WinForms to copy stuff to the clipboard. When testing, I try to always fire up PowerShell with -NoProfile to make sure that I'm testing in more of a "clean state".

[rkeithhill]

Closed issue as "by design".