How to execute a powershell script using c# and setting execution policy?

Question

I tried to combine two answers from stackoverflow (first & second)

InitialSessionState iss = InitialSessionState.CreateDefault();
// Override ExecutionPolicy

PropertyInfo execPolProp = iss.GetType().GetProperty(@"ExecutionPolicy");
if (execPolProp != null && execPolProp.CanWrite)
{
    execPolProp.SetValue(iss, ExecutionPolicy.Bypass, null);
}
Runspace runspace = RunspaceFactory.CreateRunspace(iss);
runspace.Open();

Pipeline pipeline = runspace.CreatePipeline();

//Here's how you add a new script with arguments
Command myCommand = new Command(scriptfile);
CommandParameter testParam = new CommandParameter("key","value");
myCommand.Parameters.Add(testParam);

pipeline.Commands.Add(myCommand);

// Execute PowerShell script
results = pipeline.Invoke();

In my powershell script I have the following parameter:

Param(
[String]$key
)

However, when I execute this, then I get the following exception:

System.Management.Automation.CmdletInvocationException: Cannot validate argument on parameter 'Session'. 
The argument is null or empty. 
Provide an argument that is not null or empty, and then try the command again.

mklement0 · Accepted Answer · 2025-01-12 00:34:53Z

7

Without knowing what your specific problem was, note that your C# code can be greatly streamlined, which may also resolve your problem:

There is no need to resort to reflection in order to set a session's execution policy.
Using an instance of the PowerShell class greatly simplifies command invocation.

// Create an initial default session state.
var iss = InitialSessionState.CreateDefault2();
// Set its script-file execution policy (for the current session only).
iss.ExecutionPolicy = Microsoft.PowerShell.ExecutionPolicy.Bypass;

// Create a PowerShell instance with a runspace based on the 
// initial session state.
PowerShell ps = PowerShell.Create(iss);

// Add the command (script-file call) and its parameters, then invoke.
var results =
  ps
   .AddCommand(scriptfile)
   .AddParameter("key", "value")
   .Invoke();

Note:

Using a per-process execution-policy override, as shown above, does not work if the current machine's / current user's execution policy is controlled by GPOs (Group Policy Objects).
- See this answer for a comprehensive overview of PowerShell's script execution policies.
The .Invoke() method only throws an exception if a terminating error occurred during execution of the PowerShell script. The more typical non-terminating errors are instead reported via .Streams.Error.

edited Jan 12 at 0:34

answered Aug 26, 2021 at 17:01

mklement0

452k68 gold badges727 silver badges986 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Abraham Zinala Over a year ago

This is interesting. So, in C# you don't have to mark a line continuation like you would in PowerShell (i.e. : the backtick ( ` ) )?

mklement0 Over a year ago

@AbrahamZinala: There is no line-continuation char. in C#, because the logic is reversed: a statement, irrespective of how many lines it spans, is only terminated by ; In PowerShell, which doesn't require explicit statement termination, you can situationally get away without a line-ending backtick, namely when the statement is unambiguously incomplete, notably after a line-ending | and, similarly, but not identically, to the ps example above: a line-ending . - that is, the . must be at the end of the line for PowerShell to know that the statement continues.

mklement0 Over a year ago

@AbrahamZinala: As an explicit exception, PowerShell (Core) 7+ now allows you to place a | on the next line in order to continue a pipeline. That is, while Windows PowerShell only supports, e.g. Get-Date |<newline> Format-List, PowerShell (Core) 7+ now also supports Get-Date<newline>| Format-List, albeit only in scripts, because interactively Get-Date would execute by itself before you get a chance to continue the statement (except inside { ... }).

Collectives™ on Stack Overflow

How to execute a powershell script using c# and setting execution policy?

1 Answer 1

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related