Passing Variables from C# to Powershell

Question

I am working on a C# project that that is supposed to grab a string variable (file path) and pass it to PowerShell script to have further commands done with it. I have been looking around online and through Stack and have not been able to find something that works for me...

Here is my C# code as it stands right now:

string script = System.IO.File.ReadAllText(@"C:\my\script\path\script.ps1");

using (Runspace runspace = RunspaceFactory.CreateRunspace())
{

    runspace.Open();
    PowerShell ps = PowerShell.Create();
    ps.Runspace = runspace;
    ps.AddScript(script);
    ps.Invoke();
    ps.AddCommand("LocalCopy");

    foreach (PSObject result in ps.Invoke())
    {
        Console.WriteLine(result);
    }
}

Here is my PowerShell script:

Function LocalCopy
{
    Get-ChildItem -path "C:\Users\file1\file2\file3\" -Filter *.tib -Recurse | 
    Copy-Item -Destination "C:\Users\file1\file2\local\"
}

What I want to do is have the first part of the the script: "C:\Users\file1\file2\file3\" replaced with (what i am assuming would be) a variable that I could pass from the C# code to the PowerShell script. I am very new to working with PowerShell and am not quite sure how I would go about doing something like this.

---EDIT---

I am still having issues with my code, but i am not getting any errors. I believe that it is because the variable is still not being passed through...

C# code:

string script = System.IO.File.ReadAllText(@"C:\my\script\path\script.ps1");

using (Runspace runspace = RunspaceFactory.CreateRunspace())
{

    runspace.Open();
    PowerShell ps = PowerShell.Create();
    ps.Runspace = runspace;
    ps.AddScript(script);
    ps.Invoke();
    ps.AddArgument(FilePathVariable);
    ps.AddCommand("LocalCopy");

    foreach (PSObject result in ps.Invoke())
    {
        Console.WriteLine(result);
    }
}

PowerShell code:

Function LocalCopy
{
    $path = $args[0]
    Get-ChildItem -path $path -Filter *.tib -Recurse | 
    Copy-Item -Destination "C:\Users\file1\file2\local\"
}

Any help would be much appreciated. Thanks!

Have you looked at the Runspace.InitialSessionState.Variables property? — Sam Goldberg
– Sam Goldberg, Commented Aug 13, 2013 at 13:49

Keith Hill · Accepted Answer · 2013-08-14 16:37:52Z

6

I would go the route Anand has shown to pass a path into your script. But to answer the question posed by your title, here's how you pass variable from C#. Well this is really how you set the variable in the PowerShell engine.

ps.Runspace.SessionStateProxy.SetVariable("Path", @"C:\Users\file1\file2\file3\");

Note: in C# for file paths you really want to use verbatim @ strings.

Update: based on your comments, try this:

runspace.Open();
PowerShell ps = PowerShell.Create();
ps.Runspace = runspace;
ps.AddScript(script, false); // Use false to tell PowerShell to run script in current 
                             // scope otherwise LocalCopy function won't be available
                             // later when we try to invoke it.
ps.Invoke();
ps.Commands.Clear();
ps.AddCommand("LocalCopy").AddArgument(FilePathVariable);
ps.Invoke();

edited Aug 14, 2013 at 16:37

answered Aug 13, 2013 at 16:41

Keith Hill

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7 Comments

scapegoat17 Over a year ago

if i needed to pass the file path through as a variable would i just do it like so ps.Runspace.SessionStateProxy.SetVariable("Path", variablepath);?

Keith Hill Over a year ago

If you needed to set a PowerShell variable called $Path that would then get used by your script, then yes. This is how you would do it. However, in your case, you could just pass the the path via a C# variable to your function invocation as @Anand has shown except that you can do this ps.AddArgument(someCSharpVariable). You will need to modify your function to use either a param($path) block or use $path = $args[0]. Then use that variable with the command: gci $path *.tib -r.

scapegoat17 Over a year ago

I have just updated my code to what i currently am working with. I do not really understand what is going on with the $path = $args[0], but i still feel that my error is coming through either the c# or powershell code where i have updated it. Do you have any ideas/explanations as to what i am doing?

Keith Hill Over a year ago

You need to add the argument to the function invocation e.g. ps.AddCommand("LocalCopy").AddArgument(FilePathVariable). See the update to my answer as there is more to this to get it to work.

scapegoat17 Over a year ago

I actually just figured that out in between posts, but i just moved the powershell portion outside of the function instead of doing what you suggested. I might try what you did instead since it seems to look a little cleaner.

|

Anand · Accepted Answer · 2013-08-13 13:32:20Z

5

ps.AddArgument("C:\Users\file1\file2\file3\");

you can use args to fetch the argument in powershell.

$path = $args[0]

MSDN

edited Aug 13, 2013 at 13:32

answered Aug 13, 2013 at 13:29

Anand

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2 Comments

scapegoat17 Over a year ago

So I am assuming that if I wanted to keep it as a variable on the C# side i could just do: ps.AddArgument(pathvaribale);?

Keith Hill Over a year ago

The OP problem's was a little more fundamental than just adding an argument for the function. When ps.AddScript(script) executes, it executes the script in a new scope so that the defined function is not available after it is invoked. You have to pass false to get the script to run in the current scope so the function remains after the script is invoked e.g. ps.AddScript(script, false);

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