Add-FormatTable.ps1

function New-FormatTableItem {
    <#
        .SYNOPSIS
            Create new format Table Item
        .DESCRIPTION
            Create new format Table Item for use with Add-FormatTable
        .EXAMPLE
            Assuming you have a custom object with a type name of 'Custom.UserType':

            @(
                (New-FormatTableItem 'First Name' 'FirstName' 20),
                (New-FormatTableItem 'Last Name' 'LastName' 20),
                (New-FormatTableItem 'Sex' 'Sex' 10),
                (New-FormatTableItem 'E-mail' 'Email' 20)
            ) | Add-FormatTable -TypeName 'Custom.UserType'

            This will add a custom table formatting definition for the specified type name.
        .NOTES
            Based on a function by Lee Holmes in his excellent Windows PowerShell Cookbook (O'Reilly)
            Author: Øyvind Kallstad
            Date: 09.11.2014
            Version: 1.0
    #>
    [CmdletBinding()]
    param (
        [Parameter()]
        [string] $Label,

        [Parameter(Mandatory)]
        [string] $PropertyName,

        [Parameter()]
        [int] $Width = 20,

        [Parameter()]
        [System.Management.Automation.Alignment] $Alignment = 'Undefined'
    )

    $tableControlColumnHeader = New-Object -TypeName System.Management.Automation.TableControlColumnHeader $Label, $Width, $Alignment
    $tableControlColumn = New-Object -TypeName System.Management.Automation.TableControlColumn $Alignment, (New-Object -TypeName System.Management.Automation.DisplayEntry $PropertyName, 'Property')
    
    Write-Output ([PSCustomObject] @{
        TableControlColumnHeader = $tableControlColumnHeader
        TableControlColumn = $tableControlColumn
    })
}

function Add-FormatTable {
    <#
        .SYNOPSIS
            Add table formatting definition for the specified type
        .EXAMPLE
            Assuming you have a custom object with a type name of 'Custom.UserType':

            @(
                (New-FormatTableItem 'First Name' 'FirstName' 20),
                (New-FormatTableItem 'Last Name' 'LastName' 20),
                (New-FormatTableItem 'Sex' 'Sex' 10),
                (New-FormatTableItem 'E-mail' 'Email' 20)
            ) | Add-FormatTable -TypeName 'Custom.UserType'

            This will add a custom table formatting definition for the specified type name.
        .NOTES
            Based on a function by Lee Holmes in his excellent Windows PowerShell Cookbook (O'Reilly)
            Author: Øyvind Kallstad
            Date: 09.11.2014
            Version: 1.0
    #>
    [CmdletBinding()]
    param (
        [Parameter(Mandatory)]
        [string] $TypeName,

        [Parameter(ValueFromPipelineByPropertyName)]
        [System.Management.Automation.TableControlColumnHeader[]] $TableControlColumnHeader,
        
        [Parameter(ValueFromPipelineByPropertyName)]
        [System.Management.Automation.TableControlColumn[]] $TableControlColumn
    )

    BEGIN {
        $table = New-Object System.Management.Automation.TableControl
        $row = New-Object System.Management.Automation.TableControlRow
    }

    PROCESS {
        foreach($item in $TableControlColumn) {
            $row.Columns.Add($item)
        }

        foreach($header in $TableControlColumnHeader) {
            $table.Headers.Add($header)
        }
    }

    END {
        $table.Rows.Add($row)

        $formatView = New-Object System.Management.Automation.FormatViewDefinition 'TableView', $table
        $extendedType = New-Object System.Management.Automation.ExtendedTypeDefinition $TypeName
        $extendedType.FormatViewDefinition.Add($formatView)
        [Runspace]::DefaultRunspace.InitialSessionState.Formats.Add($extendedType)
        Update-FormatData
    }
}