System Requirements:
- .NET 4.0 (the project could be run in .NET 2.0+ by changing the target version)
- Windows machine - code tested on Windows Server 2003, Windows Vista and Windows XP
Development:
- Language - C#
- IDE - Visual Studio 2010
Properties of Captcha Control:
The following properties can be set for the user control:
- BackgroundImagePath - the path to the background image of captcha text. This property supports local file system path. Use the "~" notation at the start of the path attribute so it can be found by Server.MapPath(path) method.
- CaptchaLength - the length of captcha text. Default is 6. Values less than 5 and over 12 are reset to 12.
- CharacterSet - the set of characters to be used for the captcha. Default is all upper case letters and 1-9 numeric. I would recommend using only upper or lower case letters as this simplifies the text.
- TestButtonText - the text to the Captcha validation button.
- ReLoadButtonText - the text to Captcha Reload button
- SpeakButtonText - the text for the Speak button
- TextColor - text color of captcha text. Use your judgment in setting the color as the captcha may not be readable if color is not properly chosen.
- FontFamily - Font family of captcha text. Default is Arial.
- FontSize - Font size of captcha text. Supports value between 12 and 24. Other values set are automatically changed to 14px.
- SuccessMessage - message to display if value entered is correct.
- ErrorMessage - message to display if value entered is incorrect.
Example:
The default.aspx page is created as an example page. The user control CaptchaControl.ascx is added and the properties are set.
Styling the controls:
The user control consists of Buttons, Textbox and Label controls. CSS styles can be applied to these controls. Currently default styles are set.