passing parameters to powershell from c#

Question

Hi,

I'm trying to pass a parameter to powershell from c# web app, but keep getting an error

Reason = {"The term 'Param($ds)\r\n\r\n$ds\r\n\r\n\r\n' 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."}

my powershell script is as follows:

Param($ds)

write-host $ds

my c# is:

    protected void drpCluster_SelectedIndexChanged(object sender, EventArgs e)
    {
        // Looping through all the rows in the GridView
        foreach (GridViewRow row in GridVMApprove.Rows)
        {
            if (row.RowState == DataControlRowState.Edit)
            {
                //create dynamic dropDowns for datastores
                DropDownList drpDatastore = (DropDownList)row.FindControl("drpDatastore");
                DropDownList drpCluster = (DropDownList)row.FindControl("drpCluster");
                var Datacenter = "'" + drpCluster.SelectedValue + "'";
                strContent = this.ReadPowerShellScript("~/scripts/Get-DatastoresOnChange.ps1");
                this.executePowershellCommand(strContent, Datacenter);
                populateDropDownList(drpDatastore);
            }
        }
    }

    public string ReadPowerShellScript(string Script)
    {
        //Read script
        StreamReader objReader = new StreamReader(Server.MapPath(Script));
        string strContent = objReader.ReadToEnd();
        objReader.Close();

        return strContent;
    }

    private string executePowershellCommand(string scriptText, string scriptParameters)
    {
        RunspaceConfiguration rsConfig = RunspaceConfiguration.Create();
        PSSnapInException snapInException = null;
        PSSnapInInfo info = rsConfig.AddPSSnapIn("vmware.vimautomation.core", out snapInException);
        Runspace RunSpace = RunspaceFactory.CreateRunspace(rsConfig);
        RunSpace.Open();
        Pipeline pipeLine = RunSpace.CreatePipeline();
        Command scriptCommand = new Command(scriptText); 
        pipeLine.Commands.AddScript(scriptText);
        if (!(scriptParameters == null))
        {
            CommandParameter Param = new CommandParameter(scriptParameters);
            scriptCommand.Parameters.Add(Param);
            pipeLine.Commands.Add(scriptCommand);              
        }

        // execute the script
        Collection<PSObject> commandResults = pipeLine.Invoke();


        // close the runspace
        RunSpace.Close();

        // convert the script result into a single string
        System.Text.StringBuilder stringBuilder = new System.Text.StringBuilder();
        foreach (PSObject obj in commandResults)
        {
            stringBuilder.AppendLine(obj.ToString());
        }

        OutPut = stringBuilder.ToString();
        return OutPut;
    }

i've followed some other threads but can't script to execute. My Powershell scripts executes if i run it from powershell console just calling the script and a parameter. if i remove Param($ds) from the powershell script it doesn't error.

can anyone help?

thanks.

Answer 1

Only scriptblocks, ps1/psm1 files and functions/filters can have a param block. The script you should be adding with AddScript should be of the form:

& { param($ds); $ds }

& is the call operator. In your example, you are trying to execute param as a command.

update

You must pass the arguments to the scriptblock like so:

& { param($ds); $ds } 42

This results in 42 being passesd to the scriptblock. Sticking script in with AddScript doesn't implicitly create a ps1 file. It's akin to you typing:

ps c:\> param($ds); $ds

...directly at the prompt; this is meaningless. Make sense?

-Oisin