Output message to Console window if command line parameters incorrect

Question

Can anyone help me output a message to a console box when my .exe is called with the wrong parameters?

Yesterday, some very kind people helped me work out how to call my app without a UI

Here is the thread

command line to make winforms run without UI

So, I have told my app to respond to "/silent archive=true transcode=true" and runs without a UI. Great!

Is it possible to output a message to the command window if they get the command incorrect?

as in "Parameters must be specified like this: /silent archive=true transcode=true"

I have tried this but nothing displays in the dos window..

static void Main(string[] args)
    {
        if (args.Length > 0)
        {
            if (args[0] == "/silent")
            {
                bool archive = false;
                bool transcode = false;

                try
                {
                    if (args[1] == "transcode=true") { transcode = true; };
                    if (args[2] == "archive=true") { archive = true; };
                    Citrix_API_Tool.Engine.DownloadFiles(transcode, archive);
                }
                catch
                {
                    Console.Write ("Hello");
                    Console.ReadLine();
                    return;
                }
            }
        }
        else

@TonyHopkinson: Not if it's already detached from the console... which a WinForms app would be default, IIRC. You really want a binary which will run without a console if started without one... but hang on to the current console if it's run from the command line. — Jon Skeet, Nov 15 '13 at 16:13
@JonSkeet I think you have hit the nail on the head there! No idea how to do what you have suggested though! LOL — Trevor Daniel, Nov 15 '13 at 16:17
@TonyHopkinson and you shouldn't send error messages to standard output anyway, that's what `Console.Error.Write` is for. — Jon Hanna, Nov 15 '13 at 16:49
@GaryWalker not quite, in this case one wants to attach to the parent console. — Jon Hanna, Nov 15 '13 at 16:51
This answer might be helpful: http://stackoverflow.com/questions/1953424/is-there-a-way-to-start-open-the-console-from-a-winforms-wpf-application — Adrian Zanescu, Nov 15 '13 at 16:52
@GaryWalker ugh. I see, they attached to the foreground window. Nasty! Shall add comment. — Jon Hanna, Nov 15 '13 at 17:02
The original answered already explained that what they were showing as an example was ugly and not recommended. When you do garbage like this, your tend to encounter nasty hacks :-) — Gary Walker, Nov 15 '13 at 17:06
Ah never read what you'd done. I usually write two exes when I want console or GUI — Tony Hopkinson, Nov 15 '13 at 22:03

score 0 · Answer 1 · answered Nov 15 '13 at 16:48

internal sealed class Program
{
  [DllImport("kernel32.dll")]
  private static extern bool AttachConsole(int dwProcessId);

  private const int ATTACH_PARENT_PROCESS = -1;
  [STAThread]
  private static void Main(string[] args)
  {
    if(false)//This would be the run-silent check.
    {
      Application.EnableVisualStyles();
      Application.SetCompatibleTextRenderingDefault(false);
      Application.Run(new MainForm());
    }
    try
    {
      throw new Exception("Always throw, as this tests exception handling.");
    }
    catch(Exception e)
    {
      if(AttachConsole(ATTACH_PARENT_PROCESS))
      {
        //Note, we write to Console.Error, not Console.Out
        //Partly because that's what error is for.
        //Mainly so if our output were being redirected into a file,
        //We'd write to console instead of there.
        //Likewise, if error is redirected to some logger or something
        //That's where we should write.
        Console.Error.WriteLine();//Write blank line because of issue described below
        Console.Error.WriteLine(e.Message);
        Console.Error.WriteLine();//Write blank line because of issue described below
      }
      else
      {
        //Failed to attach - not opened from console, or console closed.
        //do something else.
      }
    }
  }      
}

A problem is that the console would have already returned to taking input from the user. Hence you really want to try to have your exception as fast as you can if you're going to have it, so a fast validation check rather than an exception that might happen down the line, is preferable.

Output message to Console window if command line parameters incorrect

1 Answers1