Public/Network/Test-EmailAddress.ps1

function Test-EmailAddress {
  <#
.SYNOPSIS
    Tests validity if specified string is an email address.
.DESCRIPTION
    Casts the passed value as "System.Net.Mail.MailAddress" data type.
    If successful it parses string into the properties: DisplayName, User, Host, Address
    White space normally delimits the DisplayName from the address so an extra check
    is performed to see if EmailAddress specified matches the resolved Address property
.EXAMPLE
    Test-EmailAddress -EmailAddress "user@gmail.com"
 
    Would return:
    True
.EXAMPLE
    Test-EmailAddress "bademail"
 
    Would return:
    False
.EXAMPLE
    Test-EmailAddress "test user@gmail.com" -verbose
 
    Would return:
    VERBOSE: You entered email address: [test user@gmail.com]
    VERBOSE: Address resolved to: [user@gmail.com]
    VERBOSE: [user@gmail.com] does not match [test user@gmail.com]
    VERBOSE: The address is NOT valid.
    False
.EXAMPLE
    Test-EmailAddress -EmailAddress "user@gmail.com" -verbose
 
    Would return:
    VERBOSE: You entered email address: [user@gmail.com]
    VERBOSE: Address resolved to: [user@gmail.com]
    VERBOSE: Address valid, no guarantee that address [user@gmail.com] exists.
#>


  [CmdletBinding(ConfirmImpact = 'None')]
  [Outputtype('bool')]
  Param (
    [parameter(Mandatory, HelpMessage = 'Add help message for user', Position = 0, ValueFromPipeLine, ValueFromPipeLineByPropertyName)]
    [Alias('Address')]
    [string] $EmailAddress
  )

  begin {
    Write-Invocation $MyInvocation
  }

  process {
    Out-Verbose "You entered email address: [$($EmailAddress)]"
    try {
      $temp = [System.Net.Mail.MailAddress] $EmailAddress
      Out-Verbose "Address resolved to: [$($temp.Address)]"
      if ($temp.Address -ne $EmailAddress) {
        Out-Verbose "[$($temp.Address)] does not match [$($EmailAddress)]"
        Write-Output -InputObject $false
      } else {
        Out-Verbose "Address valid, no guarantee that address [$($EmailAddress)] exists."
        Write-Output -InputObject $True
      }
    } catch {
      Out-Verbose 'The address is NOT valid.'
      Write-Output -InputObject $False
    }
  }

  end {
    Out-Verbose $fxn "Complete."
  }
}