Tips - About [DateTime].md

About [DateTime]

DaysInMonth property

The class [DateTime] has an interesting property : DaysInMonth The syntax is : [DateTime]::DaysInMonth(<Year>, <Month>) i.e.

$Current Date / Times
$CurrentYear = $((Get-Date).Year) #Current Year
$CurrentMonth = $((Get-Date).Month) #Current Month
$LastDayofCurrentMonth = [DateTime]::DaysInMonth($CurrentYear, $CurrentMonth)
Write-Host "Current Year is $CurrentYear " -ForegroundColor Green
Write-Host "Current  Month is $CurrentMonth" -ForegroundColor Green
Write-host "Last Day of CurrentMonth is $LastDayofCurrentMonth" -ForegroundColor Green
Current Year is 2020
Current  Month is 2
Last Day of CurrentMonth is 29

This Could be useful when we want to work with date.

First Day of the month

To get the first day of the month we can do like the following

$FirstDateTimeoftheMonth = Get-Date -Day 1 -Month $CurrentMonth -Year $CurrentYear -Hour 0 -Minute 0 -Second 0
$FirstDateTimeoftheMonth
samedi 1 février 2020 00:00:00

Of course, this object is a [DateTime] object, then we can query its specifics property.

$FirstDateTimeoftheMonth.Date
$FirstDateTimeoftheMonth.Day
$FirstDateTimeoftheMonth.DayOfWeek

Last [DateTime] of the month

Use the previous var to build an new [DateTime] object giving the desired information

$LastDateTimeoftheMonth = Get-Date -Day $LastDayofCurrentMonth -Month $CurrentMonth -Year $CurrentYear -Hour 23 -Minute 59 -Second 59

references : https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/get-date?view=powershell-7