Introduction:

Creating a poll on your website enables you to find out more about the interests of the user. I recently added a weekly poll system to GridViewGuy. In this article I will explain how to create an AJAX enabled polling system using ASP.NET client callbacks.

Database Schema:

The database schema consists of only two tables:

1)    PollQuestions: This table holds all the questions for the poll.

2)    PollChoices: This table holds the choices of the poll questions.

Take a look at the schema shown below:

Poll Control Architecture:

I wanted to create the polling user control in a way that it does not depend on the Page. Let’s take a look at the class diagram below:

Now, let me explain each class in details:

IPoll: IPoll is an interface which will be used by all the polling classes.

WeeklyPoll: This is the class responsible for creating weekly polls. It implements the IPoll interface.

PollQuestion: This is an entity class which maps to the PollQuestions table in the database.

PollChoice: This is an entity class which maps to the PollChoices table in the database.

PollTableHelper: This is a helper class which is used to generate dynamic HTML tables.

ControlToHtmlConvertor: This class contains helper methods to convert a control into pure HTML.

DataAccess: This class serves as the DataAccess class and used to INSERT and SELECT polls from the database.

Implementation:

Let’s dive into the implementation details. We will see few important classes in this article. For complete implementation you can download the code at the end of this article.

IPollInterface: