In this example, we will create a web page which will track and display
the hit counts for the web site. ASP developers must be familiar with
a similar technique used to track the hit counts in classic ASP web
This web page can be easily re-used in the application, enabling you
to provide the functionality in multiple web pages.
track the hit count in a text file on the web server. We could have
used an Application variable for the same job or persisted the value
to a database.
To display the hit count, we read the current value from the text
file, and increment it by one. We use GDI+ classes to create the image
to display the counter value. Alternatively, this counter can be rendered
using 10 pre-created images, displaying numbers from 0 to 9 and arranged
to indicate the counter value. Creating graphic images on the fly
to display the counter will allow us to extend our sample to customize
the look and feel of the counter.
We will create a Visual C# web application and add a web page in the
new project. This web page will hold the core functionality of managing
the hit counter in the text file and returning a graphic image to
render the counter value.
This web page does not contain any server controls. In the Page_Load
event, add the following code.
The above code invokes methods to get the counter value and render
the image for the counter value.
Letís take a look at the code that fetches the counter value.
The above function just reads the value from a text file. If the text
file does not exist, the default value of 0 is used. The counter is
incremented and the new value is saved in the same text file for the
next invocation. The hit counter value is then returned to the calling
The DrawCounter function uses GDI+ classes from the .Net Framework
to render an image containing the counter value. Letís take a look
at this function.
Now we have a web page that draws a custom gif image containing the
hit counter value. Letís see how to use this functionality in our
application web pages.
In the web page where you want to display the hit counter, you can
add an image control. Set the ImageUrl property of the web page to
point to the first web page. When the page is requested, the image
will display the value of the hit counter.
Figure: The hit counter is displayed in our web form.
- You can expand the sample by adding code to enhance/customize the
hit counter image.
- You can make use of caching strategies and/or cookies to prevent
the counter from incrementing on every page refresh.
About the Author:
Dipal Choksi is a Bachelor of Engineering (Computer Science). She
has industry experience in team-effort projects and also as an individual
contributor. She has worked on Visual Basic, Visual C++, Java, Directory
Services, ASP projects
Read this newsletter at: http://archive.devnewz.com/2004/0127.html