I am trying to use ValidateLength declaration with Read-Host, however I cannot get it to work. If I use it without Read-Host it works flawless. Here are some basic examples:
[ValidateLength(1,3)]$test = '123'
[ValidateLength(1,3)]$test1 = Read-Host
123
Attribute cannot be added because it would cause the variable test1 with value
123 to become invalid.
At line:1 char:1
+ [ValidateLength(1,3)]$test1 = Read-Host
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : MetadataError: (:) [], ValidationMetadataExcepti
on
+ FullyQualifiedErrorId : ValidateSetFailure
Is it possible to use ValidateLength declaration with Read-Host?
Declare your Read-Host as a string (since ValidateLength can not accept anything except a string) and the problem is solved.
[ValidateLength(1,3)]$test1 = [String](Read-Host "Input")
I am not sure why you have to cast a type on it, but it solves the problem.
Related
PowerShell version: 5.x, 6
I'm trying to create a new object of System.Collections.Generic.Dictionary, but it fails.
I tried the following "versions":
> $dictionary = new-object System.Collections.Generic.Dictionary[[string],[int]]
New-Object : Cannot convert 'System.Object[]' to the type 'System.String' required by parameter 'ComObject'. Specified method is not supported.
At line:1 char:25
+ ... ry = new-object System.Collections.Generic.Dictionary[[string],[int]]
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (:) [New-Object], ParameterBindingException
+ FullyQualifiedErrorId : CannotConvertArgument,Microsoft.PowerShell.Commands.NewObjectCommand
> $dictionary = new-object System.Collections.Generic.Dictionary[string,int]
New-Object : Cannot convert 'System.Object[]' to the type 'System.String' required by parameter 'ComObject'. Specified method is not supported.
At line:1 char:25
+ ... ionary = new-object System.Collections.Generic.Dictionary[string,int]
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (:) [New-Object], ParameterBindingException
+ FullyQualifiedErrorId : CannotConvertArgument,Microsoft.PowerShell.Commands.NewObjectCommand
I know that I can use a hashtable under PowerShell, but I want to know how to create a dictionary via the above declaration.
What am I missing?
Thx
Used type name System.Collections.Generic.Dictionary[[string],[int]] contains a comma. By Creating and initializing an array:
To create and initialize an array, assign multiple values to a
variable. The values stored in the array are delimited with a
comma…
Hence, you need to escape the comma (read the about_Escape_Characters and about_Quoting_Rules help topics). There are more options:
In Windows PowerShell, the escape character is the backtick (`),
also called the grave accent (ASCII 96).
$dictionary = new-object System.Collections.Generic.Dictionary[[string]`,[int]]
Quotation marks are used to specify a literal string. You can enclose
a string in single quotation marks (') or double quotation marks
(").
$dictionary = new-object "System.Collections.Generic.Dictionary[[string],[int]]"
or
$dictionary = new-object 'System.Collections.Generic.Dictionary[[string],[int]]'
The problem is how powershell is interpreting your argument.
When you include a comma in your string, it's now trying to bind
'System.Collections.Generic.Dictionary[[string]', '[int]]'
to the -TypeName parameter which is of type <string[]> or in the error message, <System.Object[]>. This can be solved by properly quoting your argument so it matches the expected parameter binding of <string>:
New-Object -TypeName 'System.Collections.Generic.Dictionary[[string], [int]]'
As well as the accepted answer, a dictionary can also be initialised using the syntax in the code block below, which:
removes the need to escape any characters
is much cleaner (in my opinion)
gives you intellisense (tested in PowerShell & PowerShell ISE)
$dictionary = [System.Collections.Generic.Dictionary[string,int]]::new()
... where string and int are .NET types.
I want to set environment variable in powershell that has dot in name.
This line throws an error:
$env:Test.Env.Var1 = "test111"
The property 'Var1' cannot be found on this object. Verify that the property exists and can be set.
At line:1 char:1
+ $env:Test.Env.Var1 = "test111"
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : PropertyNotFound
Is it possible to set "Test.Env.Var1" variable without using [Environment]::SetEnvironmentVariable method?
This can be done by
${env:test.value} = 'value'
Note the colon after env. This works in both powershell and pwsh
Cf. https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_variables?view=powershell-7.2#variable-names-that-include-special-characters
It can be done by
${env:Test.Env.Var1} = 'value'
source
Thanks to #4c74356b41 who provided answer in comment.
I am simply trying to create a powershell script which calculates the md5 sum of an executable (a file).
My .ps1 script:
$answer = Read-Host "File name and extension (ie; file.exe)"
$someFilePath = "C:\Users\xxx\Downloads\$answer"
If (Test-Path $someFilePath){
$stream = [System.IO.File]::Open("$someFilePath",[System.IO.Filemode]::Open, [System.IO.FileAccess]::Read)
$hash = [System.BitConverter]::ToString($md5.ComputeHash($stream))
$hash
$stream.Close()
}
Else{
Write-Host "Sorry, file $answer doesn't seem to exist."
}
Upon running my script I receive the following error:
You cannot call a method on a null-valued expression.
At C:\Users\xxx\Downloads\md5sum.ps1:6 char:29
+ $hash = [System.BitConverter]::ToString($md5.Compute ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull
To my understanding, this error means the script is attempting to do something, but another part of the script does not have any information to permit the first part of the script to work properly. In this case, $hash.
Get-ExecutionPolicy outputs Unrestricted.
What is causing this error?
What exactly is my null valued expression?
Any help is appreciated. I apologize if this is trivial and will continue my research.
References:
http://blogs.technet.com/b/heyscriptingguy/archive/2013/03/27/troubleshoot-the-invokemethodonnull-error-with-powershell.aspx
How to get an MD5 checksum in PowerShell
The simple answer for this one is that you have an undeclared (null) variable. In this case it is $md5. From the comment you put this needed to be declared elsewhere in your code
$md5 = new-object -TypeName System.Security.Cryptography.MD5CryptoServiceProvider
The error was because you are trying to execute a method that does not exist.
PS C:\Users\Matt> $md5 | gm
TypeName: System.Security.Cryptography.MD5CryptoServiceProvider
Name MemberType Definition
---- ---------- ----------
Clear Method void Clear()
ComputeHash Method byte[] ComputeHash(System.IO.Stream inputStream), byte[] ComputeHash(byte[] buffer), byte[] ComputeHash(byte[] buffer, int offset, ...
The .ComputeHash() of $md5.ComputeHash() was the null valued expression. Typing in gibberish would create the same effect.
PS C:\Users\Matt> $bagel.MakeMeABagel()
You cannot call a method on a null-valued expression.
At line:1 char:1
+ $bagel.MakeMeABagel()
+ ~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull
PowerShell by default allows this to happen as defined its StrictMode
When Set-StrictMode is off, uninitialized variables (Version 1) are assumed to have a value of 0 (zero) or $Null, depending on type. References to non-existent properties return $Null, and the results of function syntax that is not valid vary with the error. Unnamed variables are not permitted.
I am searching through the active directory for users under a specific organisation unit, that I would like to change using ADSI.
# get all users from the organizational unit
$accounts = Get-ADObject -filter 'objectClass -eq "user"' -SearchBase $dsn
# iterate over user objects
foreach ($account in $accounts) {
# unfortunately we have to use ADSI over the set-aduser cmdlet as we neeed to touch remote desktop attribues
$user = [ADSI]"LDAP://" + ($account.DistinguishedName).ToString()
# get logon name
$SamAccountName = $user.psbase.InvokeGet("SamAccountName")
# Profile Attributes
$user.psbase.InvokeSet("ProfilePath", "")
$user.psbase.InvokeSet("ScriptPath", "DIR\Logon.cmd")
$user.psbase.InvokeSet("HomeDrive", "H:")
$user.psbase.InvokeSet("HomeDirectory", "\\host\users$\${SamAccountName}")
# Remote Desktop Services Attributes
$user.psbase.InvokeSet("TerminalServicesProfilePath", "")
$user.psbase.InvokeSet("TerminalServicesHomeDirectory", "\\host\users$\${SamAccountName}")
$user.psbase.InvokeSet("TerminalServicesHomeDrive", "H:")
# Write attributes back to global catalog
$user.SetInfo()
}
This all works fine, until it comes to the $user = [ADSI]"LDAP://" + ($account.DistinguishedName).ToString() part.
Method invocation failed because [System.DirectoryServices.DirectoryEntry] does not contain a method named 'op_Addition'.
At \\tsclient\D\SourceCode\PowerShell\Set-ADUserAttributes.ps1:37 char:5
+ $user = [ADSI]"LDAP://" + ($account.DistinguishedName).ToString()
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (op_Addition:String) [], RuntimeException
+ FullyQualifiedErrorId : MethodNotFound
Exception calling "InvokeGet" with "1" argument(s): "Unspecified error
"
At \\tsclient\D\SourceCode\PowerShell\Set-ADUserAttributes.ps1:40 char:5
+ $SamAccountName = $user.psbase.InvokeGet("SamAccountName")
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : DotNetMethodException
It seems there is no query getting executed. However, $account.DistinguishedName contains the correct LDAP path (which I have tested manually).
So what am I doing wrong here?.
You're trying to append to an ADSI object by casting "LDAP://" as [ADSI] before you do the append.
Cat your strings first, then do the cast:
$user = [ADSI]("LDAP://" + $account.DistinguishedName)
The casting operation has higher precedence than the concatenation operation, so you need to do the concatenation in a subexpression, either like this:
[adsi]("LDAP://" + $account.DistinguishedName)
or like this:
[adsi]"LDAP://$($account.DistinguishedName)"
The distinguished name is automatically converted to a string here, so you don't need to manually call ToString().
I am not very familiar with powershell scripting and I'm stuck on this problem -
I need to make some operations on object retrieved like this:
$object = [ADSI]'LDAP://CN=Test User,OU=Dept,OU=Users,DC=example,DC=org'
...
$object.Commit()
this works fine, but I have to use distinguished name stored in variable - my test script looks like this, but its not working:
$object = [ADSI]'LDAP://$variable'
...
$object.Commit()
the first call to [ADSI] itself doesn't cause error, but any following operation crashes with message:
The following exception occurred while retrieving member "commit": "The server is not operational.
"
At line:1 char:10
+ $object.commit <<<< ()
+ CategoryInfo : NotSpecified: (:) [], ExtendedTypeSystemException
+ FullyQualifiedErrorId : CatchFromBaseGetMember
I'm pretty sure, that the parameter is sent in some wrong way, but I don't know, how to fix it, can anybody help?
tahnks
Try:
$object = [ADSI]"LDAP://$variable"
Single quotes don't expand variables.