I was working at a script where I created a custom object, and I wanted to to change the default properties shown when the object where written to the host. Easy enough, right? I have done this before of course, but this time I started thinking if it were possible to have the headings be different when using the default view, as opposed to, let’s say when shown using Format-List.
So, consider we have an object with the following properties: ‘FirstName’, ‘LastName’ and ‘Email’.
When called, it would display like this:
FirstName LastName Email --------- -------- ----- John Michaelson jm@email.com
And using Format-List:
FirstName : John LastName : Michaelson Email : jm@email.com
But this is what I wanted my output to be when calling the object:
First Name Last Name E-mail --------- -------- ----- John Michaelson jm@email.com
This is just an example of course, and could easily have been achieved using Select-Object with a custom expression.
So why didn’t I just name my properties this way when I defined the object in the script you might ask? I asked myself the same thing, but I like a challenge, ok? Besides, what I wanted was that the heading when used with Format-Table was for the headings to be ‘First Name’, ‘Last Name’ and ‘E-mail’, while when used with Format-Table * or Format-List, they should show as ‘FirstName’, ‘LastName’, and ‘Email’. Makes sense right?
After doing a little research I decided that I needed to define a format.ps1xml file to make this happen. After a lot of trial-and-error I got it working as I wanted. Was I happy now? No, of course not. There had to be a better way! Back to Google with me, and after a while I came over a link to Windows PowerShell Cookbook by Lee Holmes, at Google Books. I actually own this book, and see that in it, he have actually written a function called Add-FormatData that let’s you add a table formatting definition for a specific type name. His function didn’t solve my little problem though, but I had enough information now to build upon his function.
I ended up with two functions; New-FormatTableItem and Add-FormatTable, which let’s you perform what I wanted like this:
@( (New-FormatTableItem 'First Name' 'FirstName' 20), (New-FormatTableItem 'Last Name' 'LastName' 20), (New-FormatTableItem 'E-mail' 'Email' 20) ) | Add-FormatTable -TypeName 'Custom.UserType'
The New-FormatTableItem functions are used to create an array of Table Items, which I then pipe into Add-FormatTable. I don’t know how useful this is going to be for you guys, but it was a fun exercise for me, so I wanted to share it. Here is the code:
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 | |
} | |
} |
Hi Øyvind,
Thanks a lot for sharing. I came across your post, since I was researching for a similar post on my blog(https://powershellone.wordpress.com/2015/03/09/powershell-format-table-views/). I came up with a similar function (Add-FormatTableView) to create custom table views (for Format-Table -View) for built-in objects.
Kind regards,
Dirk
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