Lesson 19 Exercise 4

mpthemaster · #1 (**permalink**) June 11th, 2011, 02:41 PM

How do I have the console window come up? Just typing: "Console.WriteLine(whatever)" doesn't.

Edit: I've figured out who to do it, but I don't really understand what is going on. Is this the most simplified that I could have the code to activate and deactivate the console window?

Code:

" using System.Runtime.InteropServices;
[DllImport("kernel32.dll", EntryPoint = "GetStdHandle", SetLastError = true, CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]

private static extern IntPtr GetStdHandle(int nStdHandle);

[DllImport("kernel32.dll", EntryPoint = "AllocConsole", SetLastError = true, CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]


[DllImport("kernel32.dll", EntryPoint = "FreeConsole", SetLastError = true, CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]

public static extern int FreeConsole();

"

Rod Stephens · #2 (**permalink**) June 11th, 2011, 04:08 PM

Normally you can use the console window in two ways. First, while developing a program, anything you write using Console.WriteLine appears in the Output window. If you can't find it (for example, if you closed it), then you can get it back by looking in the Debug menu's Windows submenu (I think).

Second, if you make a console application, then input and output go to a separate console window similar to what you get by running cmd.exe. When you start the program, this window will just appear and output written by Console.WriteLine will go there.

When the program ends, the window closes. A common mistake is the program runs very quickly, displays output, and the window closes, possibly before you even see it. You can use Console.ReadLine to make it wait until you press Enter. Then you can see everything before it closes.

Let me know if neither of these scenarios is what you had in mind.

(And post a review when you have a chance!)

mpthemaster · #3 (**permalink**) June 11th, 2011, 05:25 PM

******Just to let you know, the above is spam about how to make a hookah and not help at all*********

Thank you. I'm guessing you meant for me to use the output window for that exercise. I didn't realize that Console.WriteLine appears there.

The scenario that I thought you meant for the exercise was to have a console application pop-up from the windows form application when the "List Items" button is pressed. Then in the console application, all the list view items would be displayed as specified in the exercise to the user. The code I posted before allows for me to "enable" or "disable" the console application within the windows form application. I was now just wondering if you could tell me if that code only contains what is necessary to "enable" or "disable" the console application. I was on msdn, but this is still too complex for me to understand myself.

Thanks again for the quick reply. (do you want me to post a review on here or where I bought it?)

Rod Stephens · #4 (**permalink**) June 11th, 2011, 08:54 PM

Yes, it's a bit confusing that Microsoft uses Console.WriteLine to write to the Output window.

Writing there is useful for displaying debugging messages but I hardly ever make console applications. They're just not that interesting. Some authors have you start by making them because that lets them ignore the user interface so they can just cover things like variables and loops, but I think that approach is backward. The large majority of Windows applications use a user interface not a console window so why should you start by learning something you'll hardly ever use again? My opinion, anyway ;-)

Quote:

The scenario that I thought you meant for the exercise was to have a console application pop-up from the windows form application when the "List Items" button is pressed.

The point of that exercise was really to just let you loop through the items in a list. A more realistic example would create a printout showing the items in a bill of sale, but printing isn't until Lesson 33.

Quote:

I was now just wondering if you could tell me if that code only contains what is necessary to "enable" or "disable" the console application.

I'm actually not sure what you could do with that code. It's mainly a declaration of methods provided in external libraries and doesn't actually contain code to do anything with them. My guess is you could use it to create a new console window. It's pretty low-level stuff. It might be the sort of thing that a console application does automatically for you.

Quote:

Thanks again for the quick reply. (do you want me to post a review on here or where I bought it?)

Feel free to ask any questions you have and I'll try to answer as quickly as I can.

The best places to post reviews are places like Amazon where lots of people can see them.

Thanks!