Powershell 字符串未被识别为有效的日期时间

Question

I got a code to convert Date as below:

$DatePart = get-aduser -identity $AcountName -Properties * | Select-Object whenCreated
$DatePartSubs =$DatePart.whenCreated
$DatePartSubstring = $DatePartSubs.ToShortDateString()
$FinalDate = [datetime]::ParseExact($DatePartSubstring,'dd/MM/yyyy',$null)

But when i tried to format date i got below error

Where variable "$DatePartSubstring" equals:

What i did wrong and how to fix it?

Answer 1

Try this out it converts the date to the required format:

[datetime]$DatePartSubstring = "2019-06-13"
$FinalDate = $DatePartSubstring.ToString("dd/mm/yyy")
Write-Host $FinalDate -ForegroundColor Green

Answer 2

It looks like you are trying to get the date part, without the time, as a date-time object, where the time has been set to midnight. Converting to a sting and back again is the long way around. You might be better off to do the following:

$DatePart = get-aduser -identity $AcountName -Properties * | Select-Object whenCreated
$FinalDate = $DatePart.whencreated.Date

This should set final date to midnight of the day in question. Note, however, that if you attempt to display $FinalDate on the console, Powershell will implicitly convert it to a string before displaying it. In order to find out what it really is, do

$FinalDate.GetType()

Answer 3

PowerShell conveniently maps quite a lot of LDAP attributes to more friendly names and on some of the attributes it converts them to more usable object types. Especially on attributes that we would like to use as DateTime objects and that are stored in AD as Generalized-Time strings like this comes in handy.

So in your case, I would do

$CreatedDate = Get-ADUser -Identity $AcountName -Properties Created | Select-Object -ExpandProperty Created

Below a table that shows you the most commonly used attributes on users and how PowerShell maps them:

Property	Syntax	R/RW	LDAPDisplayName
AccountLockoutTime	DateTime	RW	lockoutTime, converted to local time
AccountNotDelegated	Boolean	RW	userAccountControl (bit mask 1048576)
AllowReversiblePasswordEncryption	Boolean	RW	userAccountControl (bit mask 128)
BadLogonCount	Int32	R	badPwdCount
CannotChangePassword	Boolean	RW	nTSecurityDescriptor
CanonicalName	String	R	canonicalName
Certificates	ADCollection	RW	userCertificate
ChangePasswordAtLogon	Boolean	W	If pwdLastSet = 0
City	String	RW	l
CN	String	R	cn
Company	String	RW	company
Country	String	RW	c (2 character abbreviation)
Created	DateTime	R	whenCreated
Deleted	Boolean	R	isDeleted
Department	String	RW	department
Description	String	RW	description
DisplayName	String	RW	displayName
DistinguishedName	String (DN)	R	distinguishedName
Division	String	RW	division
DoesNotRequirePreAuth	Boolean	RW	userAccountControl (bit mask 4194304)
EmailAddress	String	RW	mail
EmployeeID	String	RW	employeeID
EmployeeNumber	String	RW	employeeNumber
Enabled	Boolean	RW	userAccountControl (bit mask not 2)
Fax	String	RW	facsimileTelephoneNumber
GivenName	String	RW	givenName
HomeDirectory	String	RW	homeDirectory
HomedirRequired	Boolean	RW	userAccountControl (bit mask 8)
HomeDrive	String	RW	homeDrive
HomePage	String	RW	wWWHomePage
HomePhone	String	RW	homePhone
Initials	String	RW	initials
LastBadPasswordAttempt	DateTime	R	badPasswordTime, converted to local time
LastKnownParent	String (DN)	R	lastKnownParent
LastLogonDate	DateTime	R	lastLogonTimeStamp, converted to local time
LockedOut	Boolean	RW	msDS-User-Account-Control-Computed (bit mask 16)
LogonWorkstations	String	RW	userWorkstations
Manager	String (DN)	RW	manager
MemberOf	ADCollection	R	memberOf
MNSLogonAccount	Boolean	RW	userAccountControl (bit mask 131072)
MobilePhone	String	RW	mobile
Modified	DateTime	R	whenChanged
Name	String	R	cn (Relative Distinguished Name)
ObjectCategory	String	R	objectCategory
ObjectClass	String	R	objectClass, most specific value
ObjectGUID	Guid	R	objectGUID converted to string
Office	String	RW	physicalDeliveryOfficeName
OfficePhone	String	RW	telephoneNumber
Organization	String	RW	o
OtherName	String	RW	middleName
PasswordExpired	Boolean	RW	msDS-User-Account-Control-Computed (bit mask 8388608) (see Note 1)
PasswordLastSet	DateTime	RW	pwdLastSet, local time
PasswordNeverExpires	Boolean	RW	userAccountControl (bit mask 65536)
PasswordNotRequired	Boolean	RW	userAccountControl (bit mask 32)
POBox	String	RW	postOfficeBox
PostalCode	String	RW	postalCode
PrimaryGroup	String	R	Group with primaryGroupToken
ProfilePath	String	RW	profilePath
ProtectedFromAccidentalDeletion	Boolean	RW	nTSecurityDescriptor
SamAccountName	String	RW	sAMAccountName
ScriptPath	String	RW	scriptPath
ServicePrincipalNames	ADCollection	RW	servicePrincipalName
SID	Sid	R	objectSID converted to string
SIDHistory	ADCollection	R	sIDHistory
SmartcardLogonRequired	Boolean	RW	userAccountControl (bit mask 262144)
State	String	RW	st
StreetAddress	String	RW	streetAddress
Surname	String	RW	sn
Title	String	RW	title
TrustedForDelegation	Boolean	RW	userAccountControl (bit mask 524288)
TrustedToAuthForDelegation	Boolean	RW	userAccountControl (bit mask 16777216)
UseDESKeyOnly	Boolean	RW	userAccountControl (bit mask 2097152)
UserPrincipalName	String	RW	userPrincipalName

Get-ADUser by default returns objects with these properties: DistinguishedName, Enabled, GivenName, Name, ObjectClass, ObjectGUID, SamAccountName, SID, Surname, UserPrincipalName . If you want more, then you need to specify the extra's with the -Properties parameter. Best not use -Properties *