Write-String.ps1

filter Write-String {
    <#
    .SYNOPSIS
        Write a string representation of an object.
    .DESCRIPTION
        Write-String creates formatted string representations of an input object.
    .INPUTS
        System.Object
    .EXAMPLE
        Get-Process | Write-String
        
        Write each process object using the ToString method.
    .EXAMPLE
        Get-Process | Write-String { "$($_.Name): $($_.ID)" }
        
        Write each process object using the script block.
    .EXAMPLE
        Get-Process | Write-String -Format '{0}: {1}' -Property Name, ID
        
        Write each process object using the specified format.
    #>
    
    [CmdletBinding(DefaultParameterSetName = 'ToString')]
    [OutputType([String])]
    param (
        # The input object to write.
        [Parameter(ValueFromPipeline = $true)]
        [Object[]]$InputObject,
            
        # Write the string using a script block. The script block may include the pipeline variable, $_, to reference the input object.
        [Parameter(Position = 1, ParameterSetName = 'FromScriptBlock')]
        [ScriptBlock]$ScriptFormat,

        # Write a string using the defined format using the "-f" operator.
        [Parameter(Mandatory = $true, ParameterSetName = 'ToFormat')]
        [String]$Format,
        
        # A list of properties from the object which will be used to satisfy a format string.
        [Parameter(Mandatory = $true, ParameterSetName = 'ToFormat')]
        [String[]]$Property
    )
    
    if (($InputObject | Measure-Object).Count -gt 1) {
        $psboundparameters.Remove('InputObject')
        $InputObject | Write-String @psboundparameters
    } else {
        if ($pscmdlet.ParameterSetName -eq 'FromScriptBlock') {
            & $ScriptFormat
        } elseif ($pscmdlet.ParameterSetName -eq 'ToFormat') {
            try {
                $Format -f (foreach ($name in $Property) { $_.$name })
            } catch {
                $pscmdlet.ThrowTerminatingError($_)
            }
        } else {
            $_.ToString()
        }
    }
}

I fixed it by changing line 51 to this

$Format -f ($Property | ForEach-Object { $_.$name })