We Keep Coding

Invoked PS command to string

Is there way to convert invoked powershell command from C# to string?.
Let's say for example i have something like this:
PowerShell ps = PowerShell.Create();
ps.AddCommand("Add-VpnConnection");
ps.AddParameter("Name", "VPN_" + ClientName);
ps.AddParameter("ServerAddress", VPN_SERVER_IP);
ps.AddParameter("AllUserConnection");
ps.AddParameter("SplitTunneling", true);
ps.AddParameter("TunnelType", "L2tp");
And i would like to save invoked command to log file.
Can i somehow return whole command as string?

I believe what you want essentially is this.
PowerShell ps = PowerShell.Create();
ps.AddScript($"Add-VpnConnection -Name \"VPN_{ClientName}\" -ServerAddress {VPNServerIP} -AllUserConnection -SplitTunneling -TunnelType L2tp");
ps.Invoke();
The invoke return will contain a collection of PSObject so you can read it and save the information like you want in a log in c#.

Note: This answer does not solve the OP's problem. Instead, it shows how to capture a PowerShell command's output as a string in C#, formatted in the same way that the command's output would print to the display (console), if it were run in an interactive PowerShell session.
Out-String is the cmdlet that produces formatted, for-display representations of output objects as strings, as they would print to the screen in a PowerShell console.
Therefore, you simply need to use another .AddCommand() in order to pipe the output from your Add-VpnConnection call to Out-String:
string formattedOutput;
using (PowerShell ps = PowerShell.Create())
{
ps.AddCommand("Add-VpnConnection")
.AddParameter("Name", "VPN_" + ClientName)
.AddParameter("ServerAddress")
.AddParameter("AllUserConnection", VPN_SERVER_IP)
.AddParameter("SplitTunneling", true)
.AddParameter("TunnelType", "L2tp");
// Add an Out-String call to which the previous command's output is piped to.
// Use a -Width argument (column count) large enough to show all data.
ps.AddCommand("Out-String").AddParameter("Width", 512);
// Due to use of Out-String, a *single string* is effectively returned,
// as the only element of the output collection.
formattedOutput = ps.Invoke<string>()[0];
}
Console.Write(formattedOutput);

redirecting output from an external dll in powershell

I have a C# assembly that processes an xml file and at the end spits out the results to the console.
e.g. Console.WriteLine(_header.ToString());
I can load this dll in powershell and call the right method like this:
[sqlproj_doctor.sqlprojDoctor]::ProcessXML($file) | out-file ./test.xml
All is well.
The problem begins when I want to redirect the output. For some reason stdout is empty. What am I missing? I need to be further process the output of this dll.
Note: If I compile the same code as an executable, it correctly populates the standard output stream and I can redirect the output.
another note: as a workaround, I changed the method from void to string, and can now manipulate the returned string.

When you call [Console]::WriteLine('SomeText'), it write to PowerShell process stdout, not to command output, and so it can not be redirected from inside same PowerShell process, by standard PowerShell operators, like this:
[Console]::WriteLine('SomeText')|Out-File Test.txt
You have to spawn new PowerShell process, and redirect output of that new process:
powershell -Command "[Console]::WriteLine('SomeText')"|Out-File Test.txt
In case if some command use [Console]::WriteLine to write to console, you can capture that output without starting new PowerShell instance:
$OldConsoleOut=[Console]::Out
$StringWriter=New-Object IO.StringWriter
[Console]::SetOut($StringWriter)
[Console]::WriteLine('SomeText') # That command will not print on console.
[Console]::SetOut($OldConsoleOut)
$Results=$StringWriter.ToString()
$Results # That variable would contain "SomeText" text.
Although this does not help if command does not use [Console]::WriteLine, but write to stdout stream directly:
$OldConsoleOut=[Console]::Out
$StringWriter=New-Object IO.StringWriter
[Console]::SetOut($StringWriter)
$Stdout=[Console]::OpenStandardOutput()
$Bytes=[Console]::OutputEncoding.GetBytes("SomeText"+[Environment]::NewLine)
$Stdout.Write($Bytes,0,$Bytes.Length) # That command will print on console.
$Stdout.Close()
[Console]::SetOut($OldConsoleOut)
$Results=$StringWriter.ToString()
$Results # That variable will be empty.

Using C# to Call a PowerShell Script to Execute the Windows 'djoin' Command

I have the following Windows batch command that works successfully from the Command Prompt: djoin /provision /domain /machineou /machine /savefile
I have been able to wrap this Windows command in a PowerShell command: Invoke-Expression [djoin command] and it works well when running it locally using PowerShell.
I am failing when I try to take the script in Step #2 and call it from a C# web application. I'm trying the following:
PowerShell ps = PowerShell.Create();
ps.addCommand("Invoke-Expression");
ps.AddArgument("<djoin command>");
The web page doesn't give me any errors and I'm stuck on this. Please let me know if you have any questions and thank you for your help.

If you really want to use the PowerShell engine to execute this, then do it this way:
using (var ps = PowerShell.Create())
{
ps.AddScript("djoin /provision /domain /machineou /machine /savefile");
var results = ps.Invoke();
foreach (var r in results)
{
// do something with r
}
}
Note: the use of Invoke-Expression is unnecessary. Also, as MethodMan suggests in his comment, you could just use System.Diagnostics.Process.Start().

Calling PowerShell cmdlet from C# throws CommandNotFoundException

I'm trying to call the Add-AppxPackage cmdlet from C#. I found the MSDN article on running PowerShell from C# code. I have referenced the System.Management.Automation assembly and have tried the following code snippets, all of which result in the same exception when trying to call powerShell.Invoke():
System.Management.Automation.CommandNotFoundException was unhandled
The term 'Add-AppxPackage' is not recognized as the name of a cmdlet,
function, script file, or operable program. Check the spelling of the
name, or if a path was included, verify that the path is correct and
try again.
Snippet 1:
var powerShell = PowerShell.Create();
powerShell.AddCommand(string.Format("Add-AppxPackage '{0}'", appxFilePath));
foreach (PSObject result in powerShell.Invoke())
{
Console.WriteLine(result);
}
I understand why this doesn't work, since I shouldn't be providing parameters in the AddCommand() function.
Snippet 2:
var powerShell = PowerShell.Create();
powerShell.AddCommand("Add-AppxPackage");
powerShell.AddParameter("Path", appxFilePath);
foreach (PSObject result in powerShell.Invoke())
{
Console.WriteLine(result);
}
Snippet 3:
var powerShell = PowerShell.Create();
powerShell.AddCommand("Add-AppxPackage");
powerShell.AddArgument(appxFilePath);
foreach (PSObject result in powerShell.Invoke())
{
Console.WriteLine(result);
}
My C# project targets .Net 4.5, and if I do powerShell.AddCommand("Get-Host") it works and the Version it returns back is 4.0. Add-AppxPackage was added in v3.0 of PowerShell, so the command should definitely exist, and it works fine if I manually run this command from the Windows PowerShell command prompt.
Any ideas what I am doing wrong here? Any suggestions are appreciated.
-- Update --
I found this post and this one, and realized there is a AddScript() function, so I tried this:
Snippet 4:
var powerShell = PowerShell.Create();
powerShell.AddScript(string.Format("Add-AppxPackage '{0}'", appxFilePath));
var results = powerShell.Invoke();
foreach (PSObject result in results)
{
Console.WriteLine(result);
}
And it does not throw an exception, but it also doesn't install the metro app, and the "results" returned from powerShell.Invoke() are empty, so I'm still at a loss...
-- Update 2 --
So I decided that I would try just creating a new PowerShell process to run my command, so I tried this:
Process.Start(new ProcessStartInfo("PowerShell", string.Format("-Command Add-AppxPackage '{0}'; $key = $Host.UI.RawUI.ReadKey('NoEcho,IncludeKeyUp')", appxFilePath)));
but it still throws the same error that Add-AppxPackage is not a recognized cmdlet.
ANSWER
If you follow the long comment thread on robert.westerlund's answer, you will see that for some reason when running/launched from Visual Studio, PowerShell was not including all of the PSModulePaths that it does when running straight from a PowerShell command prompt, so many modules are not present. The solution was to find the absolute path of the module that I needed (the appx module in my case) using:
(Get-Module appx -ListAvailable).Path
And then import that module before trying to call one of its cmdlets. So this is the C# code that worked for me:
var powerShell = PowerShell.Create();
powerShell.AddScript(string.Format(#"Import-Module 'C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\Appx\Appx.psd1'; Add-AppxPackage '{0}'", appxFilePath));
var results = powerShell.Invoke();
UPDATED ANSWER
You can see from this other post I opened, that the problem was with a bug in a Visual Studio extension (in my case StudioShell) causing not all of the PSModulePaths to be loaded. After uninstalling that extension all of the modules were loaded correctly and I no longer needed to manually import the module.

In PowerShell there is a difference between terminating errors (which stops the execution) and non-terminating errors (which are just written to the error stream).
If you want to create a non-terminating error in a function of your own, just use the Write-Error cmdlet. If you want to create a terminating error, use the Throw keyword. You can read more about these concepts if you run Get-Help Write-Error, Get-Help about_Throw and Get-Help about_Try_Catch_Finally.
Using the Add-AppxPackage with a non existing package is a non terminating error and will thus be written to the error stream, but no execution halting exception will be thrown. The following code tries to add a non existing package and then writes the error to the console.
var powerShell = PowerShell.Create();
powerShell.AddScript("Add-AppxPackage NonExistingPackageName");
// Terminating errors will be thrown as exceptions when calling the Invoke method.
// If we want to handle terminating errors, we should place the Invoke call inside a try-catch block.
var results = powerShell.Invoke();
// To check if a non terminating error has occurred, test the HadErrors property
if (powerShell.HadErrors)
{
// The documentation for the Error property states that "The command invoked by the PowerShell
// object writes information to this stream whenever a nonterminating error occurs."
foreach (var error in powerShell.Streams.Error)
{
Console.WriteLine("Error: " + error);
}
}
else
{
foreach(var package in results)
{
Console.WriteLine(package);
}
}

Call external functions from multiple PowerShell scripts in C#

I have a C# application that runs PowerShell scripts after reading them off database as strings. Assume script1, script2 and utilityfunctions are scripts read from database.
var rs = RunspaceFactory.CreateRunspace();
rs.Open();
var ps = PowerShell.Create();
ps.Runspace = rs;
ps.AddScript(utilityFunctions);
ps.AddScript(script1);
Is there anyway possible that I can call functions in utilityFuntions from script1? I have tried using $MyInvocation and go through its properties but did not find anything useful. When going through ps.Commands properties, I can of course see two items but when going through commands within the script, I cannot get to anything inside utilityFunctions. I guess I can read all scripts and concatenate them as string and only pass one script but I am just wondering if there is a way to do it without string concatenation.