Verbose in class with "using module" directive

Question

I faced a specific behavior while using verbose output in class.

This works like a charm:

# SomeModule.psm1
class SomeClass {
    SomeClass() {
        Write-Verbose "It works!"
    }
}

function Test-SomeModule {
    [CmdletBinding()]
    param()
    [SomeClass]::new()
}

And console output looks as expected:

PS C:\> Test-SomeModule -Verbose
VERBOSE: It works!
PS C:\>

But! if we move the class to a separate file and import it to root module:

# SomeClass.psm1
class SomeClass {
    SomeClass() {
        Write-Verbose "It works!"
    }
}

# SomeModule.psm1
using module .\SomeClass.psm1

function Test-SomeModule {
    [CmdletBinding()]
    param()
    [SomeClass]::new()
}

There will be no verbose out, even -Verbose parameter is specified:

PS C:\> Test-SomeModule -Verbose
PS C:\>

Can anybody explain me this? Is there any way to passthrough verbose preference to the class, imported with "using module"?

mklement0 · Accepted Answer · 2025-11-29 05:59:38Z

The root cause of your problem is a long-standing, known problem:

In advanced functions, common parameters such as -Verbose are translated to function-local instances of preference variables with generally equal effect, such as $VerbosePreference = 'Continue'
However, preference variables are not seen across scope-domain ("session state") boundaries, so that a class definition from a (different) module does not respect them - which explains your symptom.
- See GitHub issue #4568 for a discussion of this long-standing problem.

Workarounds:

PowerShell (Core) 7 (v7.4+) only:
- Decorate your class definition with the [NoRunspaceAffinity()] attribute, which prevents it from binding to the scope domain of the module of origin and instead binds it to the caller's scope domain on instantiation of the class:
```
# SomeClass.psm1 - PowerShell (Core) 7.4+ only
[NoRunspaceAffinity()]
class SomeClass {
    SomeClass() {
        Write-Verbose "It works!"
    }
}        
```
- The caller's code can remain the same as in your question.
Alternative that also works in Windows PowerShell (the legacy, ships-with-Windows, Windows-only edition of PowerShell whose latest and final version is 5.1):
- Define your class in a *.ps1 (regular script file) rather than a *.psm1 file (script-module file).
```
# SomeClass.ps1 - NOTE: .ps1 rather than .psm1
class SomeClass {
    SomeClass() {
        Write-Verbose "It works!"
    }
}        
```
- Then, in the calling code, use dot-sourcing rather than using module in order to import your class definition from the .ps1 file (dot-sourced *.ps1 scripts implicitly run in the same scope domain as the caller):
```
# Caller code

# Dot-source the *.ps1 file with the class definition(s)
. .\SomeClass.ps1

function Test-SomeModule {
    [CmdletBinding()]
    param()
    [SomeClass]::new()
}
```

Maybe second workaround is not pretty, but it works. Thanks a lot!

Santiago Squarzon · Accepted Answer · 2025-11-29 17:59:57Z

1

Another workaround could be to pass the cmdlet as parameter of your constructor and use it instead of Write-Verbose to stream verbose output, this wouldn't require any change to the file structure (both can be .psm1) but would require adding the parameter in your class .ctor and passing $PSCmdlet when creating the instance of your class.

Additionally, this approach will respond correctly to -Verbose and $VerbosePreference.

# SomeClass.psm1
class SomeClass {
    SomeClass([System.Management.Automation.PSCmdlet] $cmdlet) {
        # $cmdlet could be stored in a field to use in other methods
        $cmdlet.WriteVerbose('It works!')
    }
}

# SomeModule.psm1
using module .\SomeClass.psm1

function Test-SomeModule {
    [CmdletBinding()]
    param()
    [SomeClass]::new($PSCmdlet)
}

edited Nov 29 at 17:59

answered Nov 29 at 13:24

Santiago Squarzon

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