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Get Virtual Machine names in PowerShell via C# (Hyper-V)

I am trying to get the list of virtual machine names, from a local Hyper-V server, with the following code:
string _scr = ("Get-VM | Select -ExpandProperty Name");
var _ps = PowerShell.Create();
_ps.AddScript(_scr);
Collection<PSObject> _cObj = _ps.Invoke();
foreach (PSObject _vm in _cObj)
{
Console.WriteLine(_vm);
}
The Get-VM cmdlet should return values in string format already, but I don't get any output.
I would like to get a result like the following output we get in PowerShell:
PS C:\> Get-VM | Select -ExpandProperty Name
VM-Name1
VM-Name2
VM-Name3
VM-Name4
PS C:\>
Can anyone help me with this please?
Thanks a million.
Ada

Get-VM only works in a PowerShell session run as administrator. When I try your C# code run as an administrator it does print VM names.
When I try it without administrator rights I get no output, same as you - but there is an error reported if you check _ps.HadErrors it's true. Try this version of your code:
string _scr = ("Get-VM | Select -ExpandProperty Name");
var _ps = PowerShell.Create();
_ps.AddScript(_scr);
Collection<PSObject> _cObj = _ps.Invoke();
if (_ps.HadErrors) {
Console.WriteLine(_ps.Streams.Error[0].ToString());
}
foreach (PSObject _vm in _cObj)
{
Console.WriteLine(_vm);
}
I get "You do not have the required permission to complete this task. Contact the administrator of the authorization policy for the computer {name}", you may get another error which gives you an idea what is going wrong.
(Another consideration, if the Hyper-V module is not being autoloaded you may need Import Hyper-V; at the beginning of your PowerShell code).

Why does my powershell function fail to be called from C#?

Trying to use a powershell script with a function as follows:
function MoveCompressFiles{
Param
(
[Parameter(Mandatory=$true )]
[string] $Des,
[Parameter(Mandatory=$true)]
[string] $Src
)
Add-Type -AssemblyName System.Drawing
$files = Get-ChildItem $Src
foreach ($f in $files) {
if (($f.Length / 1KB) -lt [int32]200) {
Copy-Item -Path $f.FullName -Destination $Des
}
else {
Copy-Item -Path $f.FullName -Destination $Des
while (((Get-Item (($Des).ToString() + "\$f")).Length / 1KB ) -gt 500) {
$img = [System.Drawing.Image]::FromFile((($Des).ToString() + "$f"))
[int32]$new_width = $img.Width * (20 / 100);
[int32]$new_height = $img.Height * (20 / 100);
$img2 = New-Object System.Drawing.Bitmap($new_width, $new_height)
$graph = [System.Drawing.Graphics]::FromImage($img2)
$graph.DrawImage($img, 0, 0, $new_width, $new_height)
$newImgName = "M".ToString() + $f.ToString()
$img2.Save(($Des).ToString()+"\$newImgName")
$img.Dispose()
$img2.Dispose()
Remove-Item ($Des.ToString()+$f)
Rename-Item -Path ($Des.ToString()+$newImgName) -NewName "$f"
Write-Host ((Get-Item ($Des.ToString()+$f)).Length / 1KB )
}
$filesize = $f.Length * 0.8
$filesize=($filesize / 1KB)
#$filesize = [math]::round(($filesize / 1KB), 0)
$abc = "KB"
$filesizeSTR = $filesize.ToString() + $abc
Push-Location $Src
mogrify -path $Des -define jpeg:extent=$filesizeSTR $f
Pop-Location
Write-Host "Moved file $f"
}
}
}
Works in Powershell, however when i try to do it it in my solution,
private static void Powershell()
{
string SCRIPT_PATH = System.IO.File.ReadAllText(#"C:\Untitled2.ps1");
using (Runspace runspace = RunspaceFactory.CreateRunspace())
{
runspace.Open();
PowerShell ps = PowerShell.Create();
ps.Runspace = runspace;
ps.AddScript(SCRIPT_PATH);
ps.Invoke();
ps.AddCommand("MoveCompressFiles").AddParameters(new Dictionary<string, string>
{
{"Des" , #"C:\Des"},
{"Src", #"C:\Src"}
});
}
}
It doesn't work, I've tried some other methods of calling a function from a ps script but it still fails to even move the files to another location

Since you need to dot-source your script file (. <script>) in order to make the MoveCompressFiles function available, which requires an .AddScript() call,
I suggest constructing a single piece of PowerShell code in a string variable that both dot-sources the script and invokes your function via a single .AddScript() call.
However, in order to guarantee that .AddScript() works, you must first ensure that the PowerShell execution policy allows script invocation, using a call to Set-ExecutionPolicy; the code below uses -Scope Process, so as to limit the change to the current process.
Update: There's a simpler way to configure the execution policy, via the initial session state - see this answer.
var SCRIPT_PATH = #"C:\Untitled2.ps1";
var src = #"C:\Src";
var des = #"C:\Des";
var script = $#". ""{SCRIPT_PATH}""; MoveCompressFiles -Des ""{des}"" -Src ""{src}""";
using (PowerShell ps = PowerShell.Create())
{
// Make sure that script execution is allowed.
ps.AddCommand("Set-ExecutionPolicy")
.AddParameter("Scope", "Process")
.AddParameter("ExecutionPolicy", "Bypass")
.AddParameter("Force", true);
ps.Invoke();
// Add the PowerShell code constructed above and invoke it.
ps.AddScript(script);
// Use foreach (var o in ps.Invoke()) { Console.WriteLine(o); } to print the output.
ps.Invoke();
}
Note the simplified, implicit runspace creation, by using PowerShell.Create() only.
The embedded PowerShell code dot-sources your script file (. <script>) in order to define the MoveCompressFiles function, and then invokes the function.
Note that the above, as your own code, doesn't capture or print the output from the PowerShell code (.Invoke()'s output).
To see if errors occurred, you can check ps.HadErrors and examine ps.Streams.Error or any of the other streams, such as .ps.Streams.Information for the Write-Host output (the success stream's output is what .Invoke() returns directly).
For instance, use something like the following to print all errors (messages only) that occurred to the console's standard error stream:
foreach (var o in ps.Streams.Error) {
Console.Error.WriteLine(o);
}
As for what you tried:
ps.AddScript(SCRIPT_PATH); ps.Invoke();
While this executes your script, it does so in a child scope, so the embedded function MoveCompressFiles definition is not added to your session's top-level scope, so the subsequent .AddCommand() call fails, because the MoveCompressFiles function isn't available.
Instead, you must dot-source your script (. <script>), which makes it run in the caller's scope and therefore makes its function definition available there.
As an aside: Despite the .AddScript() method's name, its primary purpose is to execute a piece of PowerShell code, not a script file.
To execute the latter (without dot-sourcing), use .AddCommand().

Script works in powershell but not c#

This script works when running in PowerShell ISE (it sets the given user's Remote Desktop Services Profile settings in Active Directory):
Get-ADUser FirstName.LastName | ForEach-Object {
$User = [ADSI]"LDAP://$($_.DistinguishedName)"
$User.psbase.invokeset("TerminalServicesProfilePath","\\Server\Share\HomeDir\Profile")
$User.psbase.invokeset("TerminalServicesHomeDrive","H:")
$User.psbase.invokeset("TerminalServicesHomeDirectory","\\Server\Share\HomeDir")
$User.setinfo()
}
But when I try running it from a C# application I get an error for each invokeset that I call:
Exception calling "InvokeSet" with "2" argument(s):
"Unknown name. (Exception from HRESULT: 0x80020006 (DISP_E_UNKNOWNNAME))"
Here is the code, which is inside my PowerShell class:
public static List<PSObject> Execute(string args)
{
var returnList = new List<PSObject>();
using (var powerShellInstance = PowerShell.Create())
{
powerShellInstance.AddScript(args);
var psOutput = powerShellInstance.Invoke();
if (powerShellInstance.Streams.Error.Count > 0)
{
foreach (var error in powerShellInstance.Streams.Error)
{
Console.WriteLine(error);
}
}
foreach (var outputItem in psOutput)
{
if (outputItem != null)
{
returnList.Add(outputItem);
}
}
}
return returnList;
}
And I call it like this:
var script = $#"
Get-ADUser {newStarter.DotName} | ForEach-Object {{
$User = [ADSI]""LDAP://$($_.DistinguishedName)""
$User.psbase.invokeset(""TerminalServicesProfilePath"",""\\file\tsprofiles$\{newStarter.DotName}"")
$User.psbase.invokeset(""TerminalServicesHomeDrive"",""H:"")
$User.psbase.invokeset(""TerminalServicesHomeDirectory"",""\\file\home$\{newStarter.DotName}"")
$User.setinfo()
}}";
PowerShell.Execute(script);
Where newStarter.DotName contains the (already existing) AD user's account name.
I tried including Import-Module ActveDirectory at the top of the C# script, but with no effect. I also called $PSVersionTable.PSVersion in both the script running normally and the C# script and both return that version 3 is being used.
After updating the property names to
msTSProfilePath
msTSHomeDrive
msTSHomeDirectory
msTSAllowLogon
I am getting this error in C#:
Exception calling "setinfo" with "0" argument(s): "The attribute syntax specified to the directory service is invalid.
And querying those properties in PowerShell nothing (no error but also no output)
Does anyone happen to know what could cause this?
Many thanks

Updated answer: It seems that these attributes don't exist in 2008+. Try these ones instead:
msTSAllowLogon
msTSHomeDirectory
msTSHomeDrive
msTSProfilePath
See the answer in this thread for the full explanation.
Original Answer:
The comment from Abhijith pk is probably the answer. You need to run Import-Module ActiveDirectory, just like you need to do in the command line PowerShell.
If you've ever run Import-Module ActiveDirectory in the PowerShell command line, you'll know it takes a while to load. It will be the same when run in C#. So if you will be running several AD commands in your application, you would be better off keeping a Runspace object alive as a static object and reuse it, which means you only load the ActiveDirectory module once.
There is details here about how to do that in C#:
https://blogs.msdn.microsoft.com/syamp/2011/02/24/how-to-run-an-active-directory-ad-cmdlet-from-net-c/
Particularly, this is the code:
InitialSessionState iss = InitialSessionState.CreateDefault();
iss.ImportPSModule(new string[] { "activedirectory" });
Runspace myRunSpace = RunspaceFactory.CreateRunspace(iss);
myRunSpace.Open();

How to incorporate ScriptBlocks into a hosted powershell environment

I've recently started to explore powershell scripting as well as powershell hosting.
From a powershell command prompt the following line executes as I would expect.
"fee" | &{ process { $_; $args } } "fi" "fo" "fum"
This script outputs the "fee" that's in the pipeline ($_) plus the "fi", "fo", and "fum" that are passed in as arguments to the scriptBlock ($args).
I am trying to achieve this same result by using the System.Management.Automation.Powershell class.
When I try this:
using (var ps = PowerShell.Create())
{
var result = ps
.AddScript(#"&{ process { $_; $args} }")
.AddArgument("fi")
.AddArgument("fo")
.AddArgument("fum")
.Invoke(Enumerable.Repeat("fee", 1));
}
my result array contains a single null element (not sure what's going on there).
If I try this:
using (var ps = PowerShell.Create())
{
var result = ps
.AddCommand("Invoke-Command")
.AddParameter("ScriptBlock", ScriptBlock.Create(#"&{ process { $_; $args } }"))
.AddParameter("ArgumentList", new string[] { "fi", "fo", "fum"})
.Invoke(Enumerable.Repeat("fee", 1));
}
only "fee" is output. The $args array is empty.
Finally, when I try this:
using (var ps = PowerShell.Create())
{
var result = ps
.AddCommand("Invoke-Command")
.AddParameter("ScriptBlock", ScriptBlock.Create(#"&{ process { $_; $args } } ""fi"" ""fo"" ""fum"""))
.Invoke(Enumerable.Repeat("fee", 1));
}
I get closest. The pipelined "fee", and the "fi", "fo", and "fum" arguments are all output. The problem with this, however, is that I ideally would prefer to dynamically pass my arguments to the scriptBlock rather than concatenating them into the script block expression.
My question is how can I create a script block in a hosted powershell environment that can both access data in the pipeline from which it is invoked as well as accept parameters? I've only been able to achieve one or the other. I am using version 4.5 of the .Net framework and version 3 of the System.Management.Automation assembly.

It's because a wrong script is used for AddScript, &{} should not be used because it is actually done by Invoke() in the C# code. Here is the PowerShell analogue of C# code that works:
$ps = [powershell]::Create()
$ps.AddScript('process { $_; $args}').
AddArgument('fi').
AddArgument('fo').
AddArgument('fum').
Invoke(#('fee'))
Output:
fee
fi
fo
fum
as expected.

Customer refuses "scripts" in the environment. How do I embed a *.ps1 in a C# app?

I have the following sample Powershell script that is embedded in my C# application.
Powershell Code
$MeasureProps = "AssociatedItemCount", "ItemCount", "TotalItemSize"
$Databases = Get-MailboxDatabase -Status
foreach($Database in $Databases) {
$AllMBStats = Get-MailboxStatistics -Database $Database.Name
$MBItemAssocCount = $AllMBStats | %{$_.AssociatedItemCount.value} | Measure-Object -Average -Sum
$MBItemCount = $AllMBStats | %{$_.ItemCount.value} | Measure-Object -Average -Sum
New-Object PSObject -Property #{
Server = $Database.Server.Name
DatabaseName = $Database.Name
ItemCount = $MBItemCount.Sum
}
}
Visual Studio offers me the following embedding options:
Every PowerShell sample I've seen (MSDN on Exchange, and MSFT Dev Center) required me to chop up the Powershell command into "bits" and send it through a parser.
I don't want to leave lots of PS1 files with my application, I need to have a single binary with no other "supporting" PS1 file.
How can I make it so myapp.exe is the only thing that my customer sees?

Many customers are averse to moving away from a restricted execution policy because they don't really understand it. It's not a security boundary - it's just an extra hoop to jump through so you don't shoot yourself in the foot. If you want to run ps1 scripts in your own application, simply use your own runspace and use the base authorization manager which pays no heed to system execution policy:
InitialSessionState initial = InitialSessionState.CreateDefault();
// Replace PSAuthorizationManager with a null manager which ignores execution policy
initial.AuthorizationManager = new
System.Management.Automation.AuthorizationManager("MyShellId");
// Extract psm1 from resource, save locally
// ...
// load my extracted module with my commands
initial.ImportPSModule(new[] { <path_to_psm1> });
// open runspace
Runspace runspace = RunspaceFactory.CreateRunspace(initial);
runspace.Open();
RunspaceInvoke invoker = new RunspaceInvoke(runspace);
// execute a command from my module
Collection<PSObject> results = invoker.Invoke("my-command");
// or run a ps1 script
Collection<PSObject> results = invoker.Invoke("c:\temp\extracted\my.ps1");
By using a null authorization manager, execution policy is completed ignored. Remember - this is not some "hack" because execution policy is something for protecting users against themselves. It's not for protecting against malicious third parties.
http://www.nivot.org/nivot2/post/2012/02/10/Bypassing-Restricted-Execution-Policy-in-Code-or-in-Script.aspx

First of all you should try removing your customer's aversion To scripts. Read up about script signing, execution policy etc.
Having said that, you can have the script as a multiline string in C# code itself and execute it.Since you have only one simple script, this is the easiest approach.
You can use the AddScript ,ethos which takes the script as a string ( not script path)
http://msdn.microsoft.com/en-us/library/dd182436(v=vs.85).aspx

You can embed it as a resource and retrieve it via reflection at runtime. Here's a link from MSDN. The article is retrieving embedded images, but the principle is the same.

You sort of hovered the answer out yourself. By adding it as content, you can get access to it at runtime (see Application.GetResourceStream). Then you can either store that as a temp file and execute, or figure out a way to invoke powershell without the use of files.

Store your POSH scripts as embedded resources then run them as needed using something like the code from this MSDN thread:
public static Collection<PSObject> RunScript(string strScript)
{
HttpContext.Current.Session["ScriptError"] = "";
System.Uri serverUri = new Uri(String.Format("http://exchangsserver.contoso.com/powershell?serializationLevel=Full"));
RunspaceConfiguration rc = RunspaceConfiguration.Create();
WSManConnectionInfo wsManInfo = new WSManConnectionInfo(serverUri, SHELL_URI, (PSCredential)null);
using (Runspace runSpace = RunspaceFactory.CreateRunspace(wsManInfo))
{
runSpace.Open();
RunspaceInvoke scriptInvoker = new RunspaceInvoke(runspace);
scriptInvoker.Invoke("Set-ExecutionPolicy Unrestricted");
PowerShell posh = PowerShell.Create();
posh.Runspace = runSpace;
posh.AddScript(strScript);
Collection<PSObject> results = posh.Invoke();
if (posh.Streams.Error.Count > 0)
{
bool blTesting = false;
string strType = HttpContext.Current.Session["Type"].ToString();
ErrorRecord err = posh.Streams.Error[0];
if (err.CategoryInfo.Reason == "ManagementObjectNotFoundException")
{
HttpContext.Current.Session["ScriptError"] = "Management Object Not Found Exception Error " + err + " running command " + strScript;
runSpace.Close();
return null;
}
else if (err.Exception.Message.ToString().ToLower().Contains("is of type usermailbox.") && (strType.ToLower() == "mailbox"))
{
HttpContext.Current.Session["ScriptError"] = "Mailbox already exists.";
runSpace.Close();
return null;
}
else
{
HttpContext.Current.Session["ScriptError"] = "Error " + err + "<br />Running command " + strScript;
fnWriteLog(HttpContext.Current.Session["ScriptError"].ToString(), "error", strType, blTesting);
runSpace.Close();
return null;
}
}
runSpace.Close();
runSpace.Dispose();
posh.Dispose();
posh = null;
rc = null;
if (results.Count != 0)
{
return results;
}
else
{
return null;
}
}
}

The customer just can't see the PowerShell script in what you deploy, right? You can do whatever you want at runtime. So write it to a temporary directory--even try a named pipe, if you want to get fancy and avoid files--and simply start the PowerShell process on that.
You could even try piping it directly to stdin. That's probably what I'd try first, actually. Then you don't have any record of it being anywhere on the computer. The Process class is versatile enough to do stuff like that without touching the Windows API directly.