Exercise: Look for hidden text somewhere within a set of files

This exercise is provided to allow potential course delegates to choose the correct Wise Owl Microsoft training course, and may not be reproduced in whole or in part in any format without the prior written consent of Wise Owl.

The answer to the exercise will be included and explained if you attend the Wise Owl course listed below!

Category ==> Visual C Sharp 2010  (65 exercises)
Topic ==> Files and folders  (3 exercises)
Level ==> Average difficulty
Course ==> Introduction to Visual C#
Before you can do this exercise, you'll need to download and unzip this file (if you have any problems doing this, click here for help).

You need a minimum screen resolution of about 700 pixels width to see our exercises. This is because they contain diagrams and tables which would not be viewable easily on a mobile phone or small laptop. Please use a larger tablet, notebook or desktop computer, or change your screen resolution settings.

To avoid having to draw the form needed for this exercise, right-click on the name of your project in Solution Explorer then choose Add --> Existing Item... (you can also press SHIFT + ALT + A to do the same thing).

Choose only the file called frmHuntKilroy.cs in the above folder to import it into your project, then edit Program.cs to make this the default form.  When you run your application, you should now see this:

Hunting Kilroy button

Click on the button to look for the word Kilroy hidden somewhere within a .cs code file.


You can now select the files in which you believe Kilroy to have gone missing:

The code files to search

Select these files, then click on the Open button to begin the search.


Hidden away in the code-behind file is the following code:

// loop over all files selected ...

foreach (string EachFile in dfoFile.FileNames)


// **************************************************

// AT THIS POINT EachFile holds the name of each file

// **************************************************


Remove the commented out code, and replace it with your code to:

  • Read in each of the selected files line by line.
  • If you find Kilroy, report on this; otherwise, just close the stream reader down.

This is what you should see when you run your program:

Message revealing where Kilroy is

Your message, of course, won't be censored like this ...


Phew - found him!  You can now close down any open forms.

This page has 0 threads Add post