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An Introduction to COM Programming with Delphi (5 / 6)
Page 3: Homework Assignment
 More of this Feature
• Page 1: Marshaling Data. Variant Reference Page.
• Page 2: Using Variants and Variant Arrays
 More Delphi COM Lessons
• TOC
• Lesson 1
• Lesson 2
• Lesson 3
• Lesson 4
• Lesson 6
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 Related Resources
• COM / OLE / ActiveX programming with Delphi

Delphi encapsulates the entire world of variants into just a handful of functions and procedures, that we've "learned" how to use. To learn even more, here's a homework assignement for you.

Homework Assignment

In this homework assignment, we will need to solidify your understanding of variant arrays. I want you do create an in-process COM server that contains a single com object. This com object has a sing function in it that enumerates the windows using the Windows API and stores the window handle and window class name into a compounded variant array. The client program will be able to make a single function call to the Com Object that returns the variant array. The client will then display the list of window handles followed by its associated class name in a list box.

Homework Summary
To do this assignment, all of the following will probably need to be used:

1) VarArrayLowBound
2) VarArrayHighBound
3) VarIsEmpty
4) VarArrayCreate
5) VarArrayReDim
6) VarArrayOf
7) VarClear
8) GetClassName
9) An EnumWindowsProc called from the EnumWindows Win API function.

Download: the solution to Lesson 5.

First page > Marshaling Data. Variant types. > Page 1, 2, 3

An Introduction to COM Programming with Delphi: Table of Content
<< Previous Lesson (4): A Com Object walk-a-bout. A Class Factory tour. Our first true COM Object program.
>> Last Lesson (6): Let's see how to make your first Type Library using Delphi.

 

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