Compare Dates in loop - date

Question

I have a requirement where I need to read a date from a CSV file and compare it to a date variable within the script. However, my code doesn't work when some of the date entries in the CSV file are blank. Any idea how I can store a blank date in [datetime] variable?
Here's the part of my code:
#This is my date variable in script
$InactivityDate = (Get-Date).AddDays(-62).Date
Import-Csv $MyCSV | ForEach {
#This is the date variable i'm reading from csv file
$whenCreated = $_.whenCreated
#This converts value in string variable $whenCreated to [DateTime] format
$ConvertWhenCreated = ([datetime]::ParseExact($whenCreated,"dd/MM/yyyy",$null))
#Comparing dates
if($ConvertWhenCreated -le $InactivityDate)
{
"Account is dormant"
}
Above code works fine when $whenCreated contains some value, but when it's blank PowerShell obviously cannot compare a date variable with blank value :(
The only solution I can see now is to check if $whenCreated is blank and save a very old date like it happens in Excel, e.g.:
if($whenCreated -eq "")
{
$whenCreated = "01/01/1900 00:00:00"
}
Should this be OK or is there another logical solution?

Answer 1

Your problem most likely isn't with the comparison, but with the conversion of the blank value to a date via ParseExact(). If you want accounts with no date treated as dormant you could simply do something like this:
$whenCreated = $_.whenCreated
if ($whenCreated) {
$whenCreated = [DateTime]::ParseExact($whenCreated, 'dd/MM/yyyy', $null)
}
if ($whenCreated -le $InactivityDate) {
'Account is dormant'
}
Checking if an empty string (or $null) is lesser or equal to $InactivityDate will return $true as long as $InactivityDate contains a date.

Answer 2

You already test if the string is empty, which is good. But there is no need to assign a fake old date, you can simply assign $null:
$InactivityDate = (Get-Date).AddDays(-62)
$dateString = "2014-11-01"
if ($dateString) {
$date = Get-Date $dateString
} else {
$date = $null
}
if ($date -le $InactivityDate) {
"Account is dormant"
}