Homework Project (Server)

1. Create 3 Com Objects that provide the implementation for the following interfaces. The names of them should be:
   1. TSystemDirectories
   2. TSystemInformation
   3. TCompleteSystemInformation
2. Create an interface called ISystemDirectories that contains 2 methods.
   1. Method 1 returns a widestring containing the windows system directory name.
   2. Method 2 returns a widestring containing the windows directory name.
3. Create another interface called ISystemInformation that contains 4 methods.
   1. Method 1 returns a widestring containing the name of the computer
   2. Method 2 returns a widestring containing the name of the keyboard
   3. Method 3 returns an Integer containing the number of function keys available on the keyboard.
   4. Method 4 returns an Integer containing the delay rate of the keyboard.
4. Create a 3rd interface called ICompleteSystemInformation that allows you to access the functionality of the previous 2 interfaces, but provides no actual implementation of the methods.

Homework Project (Client)

1. Create a new application
2. Add a TListbox component to it and name it "OutputList"
3. Add 3 buttons
   1. Get System Information button: Displays the results of the 4 methods defined in the ISystemInformation interface into the OutputList TListBox
   2. Get System Directories button: Displays the results of the 2 methods defined in the ISystemDirectories interface into the OutputList TListBox
   3. Get Complete SysInfo button: Displays all methods defined in the ISystemDirectories interface and ISystemInformation through the use of the ICompleteSystemInformation interface into the OutputList TListBox

Homework Summary
This homework isn’t that bad actually. You will probably spend more time trying to find the Win API calls that you will programming the interfaces and COM Objects. There is one major catch to this though that you must work though. It isn’t easy, but I’ve given you several clues in the Homework Project descriptions listed above. Because I am a nice guy, I’ll even give you another nugget of information:

When you instantiate a Com Object, the Class Factory never calls the objects constructor Create. It does call a certain abstract method however ... this may help with the 3rd interface I want you to build ...

Download the solution to this homework assignment.

That's all folks! (for this lesson)

First page > A Com Object walk-a-bout. A Class Factory tour. > Page 1, 1, 2, 3

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