Question

As per this sample – http://msdn.microsoft.com/en-us/library/windows/desktop/ee706590(v=vs.85).aspx,

I am trying to invoke my script in an async way. But, at the same time, I want to give feedback to the GUI on the set of operations happening i.e. want to spit the Write-verbose stuffs happening behind the scenes parallely on the GUI.

I am confused in achieving this – because I see there is a DataReady event on the PipelineReader object ? Is it possible to somehow consume that w.r.t the MSDN sample above such that I can show feedback on the GUI ?

Conceptually, I am not able to relate this sample with the DataReady event.

Answer 1

Got it ! Here is the full code…

Add a Rich Textbox = txtOutput on a Form first
& Add a reference to

C:\Program Files (x86)\Reference
Assemblies\Microsoft\WindowsPowerShell\v1.0\System.Management.Automation.dll

    IAsyncResult _invokeResult; 

    PowerShell _ps = PowerShell.Create();

    delegate void SetOutput(string value);

    // Monitor the DataAdded
    _ps.Streams.Verbose.DataAdded += new EventHandler<DataAddedEventArgs>(Verbose_DataAdded);

    var sr = new StreamReader(@"C:\MyScript.ps1");
    _ps.AddScript(sr.ReadToEnd());
    _invokeResult = _ps.BeginInvoke<PSObject>(null, null, AsyncInvoke, null);


   void Verbose_DataAdded(object sender, DataAddedEventArgs e)
   {
       System.Diagnostics.Debug.Print( ((PSDataCollection<VerboseRecord>) sender)[e.Index].ToString()) ;

       if (txtOutput.InvokeRequired)
       {
           string msg = ((PSDataCollection<VerboseRecord>) sender)[e.Index].ToString();
           txtOutput.Invoke(new SetOutput(Execute), new object[] { msg} );
       }
   }



   void AsyncInvoke(IAsyncResult ar)
   {
       // end
       try
       {
           _ps.EndInvoke(ar);
       }
       catch (Exception ex)
       {
             // do something with the error...
       }
  }

private void Execute(string msg)
        {
            txtOutput.SelectionFont = new Font(txtOutput.SelectionFont.FontFamily, 9.0f);
            txtOutput.AppendText(msg);
            txtOutput.ScrollToCaret();
        }