How to create C# async powershell method?

Question

So I want to create a way to run a powershell script asynchronously. The below code is what I have so far, but it doesn't seem to be async because it locks up the application and the output is incorrect.

    public static string RunScript(string scriptText)
    {
        PowerShell ps = PowerShell.Create().AddScript(scriptText);

        // Create an IAsyncResult object and call the
        // BeginInvoke method to start running the 
        // pipeline asynchronously.
        IAsyncResult async = ps.BeginInvoke();

        // Using the PowerShell.EndInvoke method, get the
        // results from the IAsyncResult object.
        StringBuilder stringBuilder = new StringBuilder();
        foreach (PSObject result in ps.EndInvoke(async))
        {
            stringBuilder.AppendLine(result.Methods.ToString());
        } // End foreach.

        return stringBuilder.ToString();
    }

Answer 1

You are calling it asynchronously.

However, you are then defeating the purpose by synchronously waiting for the asynchronous operation to finish, by calling EndInvoke().

To actually run it asynchronously, you need to make your method asynchronous too.
You can do that by calling Task.Factory.FromAsync(...) to get a Task<PSObject> for the asynchronous operation, then using await.