The ToString Trick

Output custom objects any way you want

PowerShell is great for dealing with custom objects.

We can easily create custom objects by casting a dictionary to [PSCustomObject] or using New-Object PSObject -Property @{}.

    [PSCustomObject]@{MyNumber = 42; MyString = 'Hello World!'}

PowerShell can also add methods to custom objects.

One of the most useful methods to add is the ToString() method.

Imagine you have some custom object and you want to make a report or a webpage

There are many ways to approach this, but one of the easiest ways is to override the ToString() method of the object.

By overriding the ToString() method, you can control how the object is represented as a string.

This page is actually an example of this trick in action

Page Source

<#
.SYNOPSIS
    The ToString Trick
.DESCRIPTION
    Output custom objects any way you want.
.NOTES        
    Output a `[PSCustomObject]` any way you want by overriding the `ToString()` method on the object.
.LINK
    https://MrPowerShell.com/Tricks/The-ToString-Trick
#>

# Create an object to represent the page.
$ThisPage = 
    [PSCustomObject]@{
        Title = 'The ToString Trick'
        Description = 'Output custom objects any way you want'
        Markdown = @(
"PowerShell is great for dealing with custom objects."
'We can easily create custom objects by casting a dictionary to `[PSCustomObject]` or using `New-Object PSObject -Property @{}`.'
"
~~~PowerShell
$({
    [PSCustomObject]@{MyNumber = 42; MyString = 'Hello World!'}
}.ToString()
)~~~
"

"PowerShell can also add methods to custom objects."

"One of the most useful methods to add is the `ToString()` method."

"Imagine you have some custom object and you want to make a report or a webpage"

"There are many ways to approach this, but one of the easiest ways is to override the `ToString()` method of the object."

"By overriding the `ToString()` method, you can control how the object is represented as a string."

"This page is actually an example of this trick in action"

        )
        Source = "$($MyInvocation.MyCommand.ScriptBlock)"
    }

# Add a ToString method to the object that formats the output as HTML.
$ThisPage | 
    Add-Member -MemberType ScriptMethod -Name ToString -Value {
        @(
            "<h1>$($this.Title)</h1>"
            "<h2>$($this.Description)</h2>"
            (ConvertFrom-Markdown -InputObject $(
                $this.Markdown -join ([Environment]::NewLine * 2)
            )).Html
            
            "<h3>Page Source</h3>" 
            "<pre><code class='language-powershell'>$([Web.HttpUtility]::HtmlEncode($this.Source))</code></pre>"
        ) -join [Environment]::NewLine
    } -Force

# Set the title and description for the page.
$title = $ThisPage.Title
$description = $ThisPage.Description

# And stringify the page.
"$thisPage"