Develop Reference

Call PS Script, Save String Returned

My PS script returns a string.
Function GetData {
Param(
[string]$id
)
Process
{
return "Value is $id"
}
GetData -id $arg
The below is the C# that calls the PS script:
PowerShell ps = PowerShell.Create();
string psScript = "GetData.ps1";
ps.AddScript(psScript);
// only takes one parameter
ps.AddParameter("25");
Collection<PSObject> results = ps.Invoke();
foreach (PSObject r in results)
{
Console.WriteLine(r.ToString());
}
Console.ReadLine();
Nothing returns.
I double checked the script and it does return a value when I pass in the path manually when calling the script directly in PowerShell. I also made sure that in the Properties of the project the Platform target is x64 (based on another question's error). I also tried to directly save the result in the Invoke method, but it gave an error, which showed that I have to actually save it in a collection, even though it's one record.
Forgot, also tried:
psParam = "25";
string psScript = "GetData.ps1 -arg'" + psParam + "'";
And no result on the console.
Tested this:
PowerShell ps = PowerShell.Create();
string psScript = ".\\GetData.ps1";
ps.AddCommand(psScript);
ps.AddArgument("25");
Collection<PSObject> results = ps.Invoke();
foreach (PSObject r in results)
{
Console.WriteLine(r.ToString());
}
Console.ReadLine();
And used most of the above and this errors because it says GetData.ps1 is not recognized as the name of a cmdlet, function, script file, or operable program. If I point directly to it by placing it on my C drive (C:\GetData.ps1), it does nothing.
Double check; inside the script I am calling the function on the last line:
GetData -id $arg
Is this correct?

Pay attention to your function. It gets an open curly brace '{', but not the matching close curly brace '}'. Your defective PowerShell code will emit an error not caught by your code.
After you correct this simple error, notice how you're calling your function. What is $arg? I assure you it's not any automatic variable. Have a look in about_automatic_variables...
P.S.: you'd better off asking enormously difficult questions like this one in social . technet . microsoft . com / Forums / windowsserver / en-US / home?forum=winserverpowershell . If you ha did it, the answer would have been posted many hours ago.

The problem is that "return" is not what you think.
In Powershell, the "return value" is the last value on the stack when execution ends. In your case, just omit the "return" keyword, and the string will come out as you expect.
Function return value in PowerShell
Alternatively, you can use Write-Output which would explicitly send the data to the output like a C-style return statement.
Note: Do NOT use Write-Host, as it writes directly to the powershell host, skipping the pipeline and never giving you a chance to see the value.

How to access PowerShell host from C#

In a PowerShell profile, one can identify the PowerShell host in order to do appropriate setup for that host's environment. For example:
if ($host.Name -eq 'ConsoleHost')
{
Import-Module PSReadline
# differentiate verbose from warnings!
$privData = (Get-Host).PrivateData
$privData.VerboseForegroundColor = "cyan"
}
elseif ($host.Name -like '*ISE Host')
{
Start-Steroids
Import-Module PsIseProjectExplorer
}
I would like to be able to do the equivalent identification from a C# context primarily because PowerShell ISE does not support Console.ReadLine so I want to know if it is safe to use it in the current PS host's environment.
I first explored trying to get the output of the Get-Host cmdlet from within C# (per Invoking a cmdlet within a cmdlet). After I located the Microsoft.PowerShell.Commands.Utility assembly (under C:\Program Files (x86)\Reference Assemblies\Microsoft\WindowsPowerShell\3.0) I could compile this but it yielded null...
var cmd = new Microsoft.PowerShell.Commands.GetHostCommand();
var myHost = cmd.Invoke();
...while this would not compile due to the InternalHost class being (ironically!) internal:
var cmd = new Microsoft.PowerShell.Commands.GetHostCommand();
var myHost = cmd.Invoke<System.Management.Automation.Internal.Host.InternalHost>();
Next, I then modified my cmdlet to inherit from PSCmdlet rather than Cmdlet (to allow access to the SessionState), so I could then access the PS host object like this:
var psVarObject = SessionState.PSVariable.GetValue("Host");
Of course, that returns a pure Object, which I then needed to cast to... oh, wait... it's still internal!... so this would not compile:
string psHost = ((System.Management.Automation.Internal.Host.InternalHost)psVarObject).Name;
Leaving me no alternative but to use reflection on a foreign assembly (horrors!):
string psHost = (string)psVarObject.GetType().GetProperty("Name").GetValue(psVarObject, null);
That works, but is less than ideal, because reflecting upon any 3rd-party assembly is a fragile thing to do.
Any alternative ideas on either (a) identifying the host or, (b) backing up a bit, being able to use the host's own Read-Host cmdlet to get a typed input from a user?

You can just use Host property from PSCmdlet class. And if you want to do Read-Host:
Host.UI.ReadLine()

When getting
var psVarObject = SessionState.PSVariable.GetValue("Host");
You can cast it to System.Management.Automation.Host.PSHost instead of InternalHost

Escaping single quotes in C# powershell runspace

I am trying to run Exchange cmdlets using System.Automation dll in C#.
In http://technet.microsoft.com/en-us/library/dd315325.aspx, they have said that for escaping single quotes, we basically need to append it with another single quote
For example,
[PS] C:\Windows\system32>Write-Host 'Live and let le''arn'
Live and let le'arn
However, when I try to do the same thing with my cmdlet,
New-Mailbox -Name 'user1.''.cn'
The new mailbox is actually created with name as user.''.cn. We would like it to be user.'.cn
Code to execute this cmdlet is as follows:
AutomatedRunspace.Command command = new AutomatedRunspace.Command(cmdlet.Command);
foreach (CmdletParameter param in cmdlet.GetParameters())
{
command.Parameters.Add(param.Name, param.Value);
}
pipeline.Commands.Add(command);
Is there anything we can do to correctly escape it?

When you're invoking cmdlets in C#, you need to also worry about the C# string quoting behavior. It's not clear in your question what exactly you're setting the Name parameter to in C# code. I would try this:
string nameArg = "user1.'.cn";
That is, the PowerShell API should be bypassing the parameter parsing phase since you're supplying the argument directly via the API.

How do I call a specific Method from a Python Script in C#?

I'm wondering if there is a possibility to call a specific Method from a Python script over a C# project.
I have no code... but my idea is:
Python Code:
def SetHostInfos(Host,IP,Password):
Work to do...
def CalcAdd(Numb1,Numb2):
Work to do...
C# Code:
SetHostInfos("test","0.0.0.0","PWD")
result = CalcAdd(12,13)
How can I call one of the Methods, from this Python script, over C#?

You can host IronPython, execute the script and access the functions defined within the script through the created scope.
The following sample shows the basic concept and two ways of using the function from C#.
var pySrc =
#"def CalcAdd(Numb1, Numb2):
return Numb1 + Numb2";
// host python and execute script
var engine = IronPython.Hosting.Python.CreateEngine();
var scope = engine.CreateScope();
engine.Execute(pySrc, scope);
// get function and dynamically invoke
var calcAdd = scope.GetVariable("CalcAdd");
var result = calcAdd(34, 8); // returns 42 (Int32)
// get function with a strongly typed signature
var calcAddTyped = scope.GetVariable<Func<decimal, decimal, decimal>>("CalcAdd");
var resultTyped = calcAddTyped(5, 7); // returns 12m

I found a similar way to do it, the call of the method is much easier with it.
C# Code goes as follows:
IDictionary<string, object> options = new Dictionary<string, object>();
options["Arguments"] = new [] {"C:\Program Files (x86)\IronPython 2.7\Lib", "bar"};
var ipy = Python.CreateRuntime(options);
dynamic Python_File = ipy.UseFile("test.py");
Python_File.MethodCall("test");
So basically I submit the Dictionary with the Library path which I want to define in my python file.
So the PYthon Script looks as follows:
#!/usr/bin/python
import sys
path = sys.argv[0] #1 argument given is a string for the path
sys.path.append(path)
import httplib
import urllib
import string
def MethodCall(OutputString):
print Outputstring
So The method call is now much easier from C#
And the argument passing stays the same.
Also with this code you are able to get a custom library folder
for the Python file which is very nice if you work in a network
with a lot of different PC's

You could make your python program take arguments on the command line then call it as a command line app from your C# code.
If that's the way to go then there are plenty of resources:
How do I run a Python script from C#?
http://blogs.msdn.com/b/charlie/archive/2009/10/25/hosting-ironpython-in-a-c-4-0-program.aspx

Changing environment variables of the calling process

This one seems trivial but the answer has eluded me for a few days now.
I have a Windows batch file, that calls a C# program to do an extra verification that cannot be done in a batch file. After the verification is complete I need to return a status and a string back to the calling shell.
Now the return value is trivial and my C# console app simply sets a return value (exit code if you will). And I thought the string will also be a piece of cake. I attempted to define a new shell variable using the:
Environment.SetEnvironmentVariable("ERR", "Some text");
This call should (and does) define a shell variable within the current process - that is the very C# process that created the variable. The value is lost as soon as the C# app terminates and the shell that created the C# app knows nothing about the variable. So... A call with no particular use... At all... Unless perhaps if I created a child process from the C3 app, perhaps it would inherit my variables.
The EnvironmentVariableTarget.Machine and EnvironmentVariableTarget.User targets for the SetEnvironmentVariable call don't solve the problem either, as only a newly created process will get these new values from the registry.
So the only working solution I can think of is:
write to stdout
write to a file
encode extra meaning into the return value
The first two are a bit ugly and the last one has its limitations and problems.
Any other ideas (how to set a shell variable in the parent process)? Maybe such shell variable modifications are a security concern (think PATH)...
Thank-you for your time.

I had the same problem as Ryan and the only thing that came to my mind as a work-around was to write a batch in error out to set the variable and to call it from the batch.
ConsoleApplication1.exe:
'put some sensible code here
'put result in variable myResult
Dim myResult As String = Guid.NewGuid().ToString("D").ToUpperInvariant()
Console.WriteLine("Normal output from the consonle app")
Console.Error.WriteLine("#ECHO OFF")
Console.Error.WriteLine("SET zzzResult={0}", myResult)
Test.cmd (the calling batch):
#ECHO OFF
:Jump to folder of batch file
PUSHD %~d0%~p0
:Define a temp file
SET zzzTempFile=%TEMP%\TMP%Random%.CMD
:Call .NET console app
ConsoleApplication1.exe 2>%zzzTempFile%
:Call the generated batch file
CALL %zzzTempFile%
:Clean up temp file
DEL %zzzTempFile%
:Clean up variable
SET zzzTempFile=
:Do something with the result
ECHO Yeah, we finally got it!
ECHO:
ECHO The value is "%zzzResult%".
ECHO:
:Clean up result variable
SET zzzResult=
:Go back to original folder
POPD
That should do the trick. And yes, I do know this is an old post and Ryan is solving other issues by now, but there might be still somebody else out there having the same problem...

What you are asking is to be able to arbitrarily write to the memory space of a running process. For good reason, this is not possible without SeDebugPrivilege.
Any of the three solutions you list will work. Stdout is the standard way to communicate with a batch script.
By the way, you're writing a Windows batch file. I'm pretty sure the ship has already sailed on "a bit ugly".

If you want to put a value of some output into a variable in the batch you can use the following construct:
FOR /F "usebackq tokens=4 delims=\[\] " %i IN (`ver`) DO set VERSION=%i
ECHO %VERSION%
Output on my OS:
6.1.7601
'usebackq' means we are using back quotes which gives the ability to use a fileset in the command quoted with double quotes. You may not need this. 'tokens' means the index in the resulting string array to select (it can be a range M-N). If you need to skip lines use 'skip=X'). 'delims' are the string separators to use (like string-Split() in .Net).
You will put your console app instead of 'ver' and adapt the delimiters and tokens to match your specific output. If you have more variables to fill you will need to make the if a bit more complex but that should make a good start.

My BAT is a bit rusty, but I think it's possible to retrieve the 'exit' code from processes you've run externally, perhaps via %ERRORLEVEL%. If that's the case, make sure to exit your program via
Environment.Exit(123); // where 123 = error code
You can't add any messages, so you'll have to do that in the .bat file.
If this isn't the case, stdout is probably the best way.

After stumbling on this myself as well recently, I came up with this approach. What I did is run the bat file using the Process class, i.e.
// Spawn your process as you normally would... but also have it dump the environment varaibles
Process process = new Process();
process.StartInfo.FileName = mybatfile.bat;
process.StartInfo.Arguments = #"&&set>>envirodump.txt";
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.RedirectStandardError = false;
process.Start();
string output = process.StandardOutput.ReadToEnd();
process.WaitForExit();
// Read the environment variable lines into a string array
string[] envirolines = File.ReadAllLines("envirodump.txt");
File.Delete("envirodump.txt");
// Now simply set the environment variables in the parent process
foreach(string line in a)
{
string var = line.Split('=')[0];
string val = line.Split('=')[1];
Environment.SetEnvironmentVariable(var, val);
}
This seems to have worked for me. It's not the cleanest approach, but will work in a bind. :)