Generating alternate colors in an email HTML table generated by PowerShell in SharePoint

Generating rich text emails with PowerShell

In this post: Generating automatic emails with embedded-reports and link to uploaded csv
we explored sending emails and attachments with HTML tables. Now let’s have a look at alternating row colors in the HTML.

This function will be used later to inject CSS reference to alternating colors into the HTML Table:

Function Set-AlternatingRows {
	
    [CmdletBinding()]
   	Param(
       	[Parameter(Mandatory=$True,ValueFromPipeline=$True)]
        [string]$Line,
       
   	    [Parameter(Mandatory=$True)]
       	[string]$CSSEvenClass,
       
        [Parameter(Mandatory=$True)]
   	    [string]$CSSOddClass
   	)
	Begin {
		$ClassName = $CSSEvenClass
	}
	Process {
		If ($Line.Contains("<tr>"))
		{	$Line = $Line.Replace("<tr>","<tr class=""$ClassName"">")
			If ($ClassName -eq $CSSEvenClass)
			{	$ClassName = $CSSOddClass
			}
			Else
			{	$ClassName = $CSSEvenClass
			}
		}
		Return $Line
	}
}

Let’s now define $a as the styles, including the style for alternating rows, which we will use when generating the HTML table:

$a = "<style>"
$a = $a + "TABLE{border-width: 1px;border-style: solid;border-color:black;}"
$a = $a + "Table{background-color:#EFFFFF;border-collapse: collapse;}"
$a = $a + "TH{border-width:1px;padding:5px;border-style:solid;border-color:black;background-color:#DDDDDD}"
$a = $a + "TD{border-width:1px;padding-left:5px;padding-right:3px;border-style:solid;border-color:black;}"
$a = $a + ".odd { background-color:#ccddee; }"
$a = $a + ".even { background-color:#eeeeff; }"
$a = $a + "</style>"

In generating the HTML table, note the reference to the above function in the Pipeline:

	$MyOutput = $table | ConvertTo-Html Title, Link, Author, Size, FileName, Modified -head $a -body "<H1>$($rows.count) $($Header)</H1>"  | Set-AlternatingRows -CSSEvenClass even -CSSOddClass odd | Convert-HTMLEscape

As a refresher, we use this function to handle HTML escaping so the HTML comes out delightfully formatted:

Function Convert-HTMLEscape {
<#
convert &lt; and &gt; to < and > It is assumed that these will be in pairs
#>

[cmdletbinding()]

Param (
[Parameter(Position=0,ValueFromPipeline=$True)]
[string[]]$Text
)

Process {
foreach ($item in $text) {
    if ($item -match "&lt;") {
        
        (($item.Replace("&lt;","<")).Replace("&gt;",">")).Replace("&quot;",'"')
     }
     else {
        #otherwise just write the line to the pipeline
        $item
     }
 }
} #close process

} #close function