Release Date: 09/03/2004
| Update Date: 09/03/2004
Scott mitchell4guysfromrolla.commicrosoft corporation
Suitable for: Microsoft ASP.NET 1.1MICROSoft ASP.NET 2.0MICROSOFT VISUAL Studio .NET
Summary: Use the inheritance of the .NET Framework to extend the ASP.NET class to generate the ASP.NET code that the disabled person is fully accessible.
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Introduction WAI, WCAG, and Section 508 Microsoft for ASP.NET 1.x Easy access ASP.NET Web control creates an adaptive, easy access to DataGrid web controls using easy-to-access DataGrid columns in the ASP.NET web page Accessibility related books in class ASP.NET 2.0
Introduction
Although most online users can use a web browser with typical browser settings to browse the Web site, but if there is a disability user usually uses other methods to access online information. For example, a blind user may use a plain text browser that converts text into Braille, or uses a screen reader to read text. A person with visual obstacles may still use a browser such as Internet Explorer, but to make a browser configured to use a large font size by means of a screen magnifying glass or by means of a browser configured to use a large font size. Action barriers may hinder the user's mouse or keyboard as an input device.
Because people with disabilities typically browse the Web using special devices or non-standard browser configurations, the overall design of a Web site and HTML tags greatly affect the user experience of persons with disabilities. For example, the font size is specified with an absolute measure unit (such as 10pt), and the font size is displayed in the absolute size and is independent of the size of the text configured in its browser. There are flash or shockwave interfaces and do not provide alternative sites in the form of a form, in fact, rejected users who use Braille devices or text speech synthesizers. One Web site is only designed to be able to convert to an alternative device, can be said to be easy to access.
At this point, you may think: "Why do I have to ensure that my web site is easy to access?" I want to have two main reasons:
1. This is a good business - according to the 2000 US census, 49.7 million Americans have disabilities; Harris Interactive Survey in June 2000 shows 43% of the United States disabled people are often online users, and disabled users Internet access The time spent is almost twice as the non-disabled user. To put the results of these two surveys, you will find that more than $ 21 million of American disabled people are often online. If you don't take time to make your Web site easy access, you will reject 21 million potential visits. 2. This is a government agency's directive - in 1998, the US government adopted the section 508 of The Rehabilitation Act, requiring the electronic information of the federal agency to be accessible for persons with disabilities. This bill provides accessibility guidelines for software applications, web applications, and telecommunications products and video products. Not only requires federal agencies to implement accessibility guidelines, but also requests to sign a contract for private companies working by the federal government. (Many countries outside the United States also have similar accessibility requirements for government agencies.) So, if you work for the government or to provide services to the government, create an easy-to-access web application is required.
In this article, we will discuss which steps can be taken to make sure your ASP.NET Web site is easy access. We will briefly look at the official accessible guidelines currently available, and then look at the accessible guidelines used by the US government. This article focuses on how to use inheritance ASP.NET web controls that will not be easy to access to meet accessible guidelines. Back to top
WAI, WCAG and Section 508
Many steps have been easier to access a Web site, but what is these steps? How many steps need to be used in a site can be seen as an easy access? These issues will vary depending on the object you ask and the accessibility level they need. For an intranet site of a Fortune 500 (Fortune 500), it is likely to have a higher level of accessibility than an intranet site with only 25 employees.
WC3 about accessibility
To help this discussion, 1999 WC3 officially established Web Accessibility Initiative (WAI), which is assigned a group that enhances Web site availability for disabled people. WAI's first action is to release Web Content Accessibility Guidelines (WCAG). WCAG provides a list of 14 guidelines to design a Web site that is easy to access.
The guidelines are not detailed in detail to make a Web site more easily access to the operations that should be taken. Specifically, they are high-level declarations for how to ensure accessibility. For example, criteria 1 is "an alternative to the auditory and visual content." Each criterion comes with a set of checkpoints. The checkpoint details the operations that can be taken to ensure accessibility criteria. Each checkpoint is given one of the following priority:
• Priority 1 - Web Developers must meet this checkpoint, otherwise one or more user groups will not access this content. • Priority 2 - Web developers should meet this checkpoint, otherwise one or more user groups will find difficult to access this content. • Priority 3 - web developers can meet this checkpoint, otherwise one or more user groups may have difficulty accessing this content.
In addition to listing the 14 guidelines and their associated, setting priority checkpoints, WCAG also provides a three-level classification level for the accessibility of the Web site. Realizing all priority 1 checkpoints is assessing as meeting A. Realizing all the priority 1 and priority 2 checkpoints are assessing as dual A, while the site that implements all checkpoints is measured as three A level. WCAG provides a good set of operations to perform, which ensures different accessibility levels.
The detailed discussion of WCAG exceeds the scope of this article. The following is the 14 high-level criteria for WCAG. The checkpoints of each criterion and their associated priorities can be found in the official Web Content Accessibility Guidelines 1.0 Specification.
1. Provide an equivalent alternative to the auditory and visual content. 2. Do not rely on color. 3. Use the tags and style sheets for proper use. 4. Explain the use of natural languages. 5. Create a form of normal conversion. 6. Make sure that the page conversion is normal in the page characteristic. 7. Make sure the user controls the time-sensitive content change. 8. Make sure the direct accessibility of the embedded user interface. 9. Designed with equipment. 10. Use a transition solution. 11. Use W3C technology and guidelines. 12. Provide context and directional information. 13. Provide a simple navigation mechanism. 14. Make sure the documentation is clear.
Visibility guidelines for US government
In 1998, the US government revised the Rehabilitation ACT to develop accessibility rules for electronics and online content maintained by the federal government. These rules are often referred to as "Section 508 Rules", which is the section 508 of the rehabilitation bill for accessibility requirements.
Note The full text of section 508 and FAQ, message boards, and training information can be found online on www.section508.gov. Other information about Section 508 can be obtained on www.access-board.gov/508.htm. For Web site accessibility, the federal government has 16 rules. The first 11 is a checkpoint from the WCAG, and the last 5 is for section 508, not the component of WCAG. These rules can be found in the Section 508 1194.22, for the full description, repeat it here:
1. A equivalent text should be provided for each non-text element. 2. Equivalent alternatives of any multimedia presentation should be synchronized with the presentation. 3. The web page should be designed so that all information conveyed by color does not require color, such as obtaining by context or tag. 4. Documents should be organized so that they can be read without the need to associate style table. 5. There should be redundant text links for each activity area mapped to the server-side image map. 6. The client image map should be provided instead of server-side image mapping, unless the area cannot be defined using the available geometry. 7. The row and column headings should be identified for data sheets. 8. For data tables with two or more logical hierarchies, you should use the data cells and title cells that are marked as these data labels. 9. The text that helps frame identification and navigation should be used to add titles to the frame. 10. The page should be designed to avoid flashing in the case where the frequency is greater than 2 Hz and less than 55 Hz. 11. When compliance with any other method, a plain text page with equivalent information or function should be provided to make the Web site in accordance with the provisions of this part. As long as the main page changes, the content of the plain text page should be updated. 12. When the page uses a scripting language to display the content or create an interface element, the information provided by the script should be consistent with the functional text that the auxiliary technology can read. 13. When the web page requires a small program, plugin, or other application on the client system to explain the page content, this page must provide a link to a plugin or applet. 14. When the electronic form is designed to complete online, the form should allow the user to access the information, field elements and functions required to complete and submit a form, including all the instructions and prompts. 15. A method should be provided allows the user to skip the repeated navigation link. 16. When a timing response is required, the user should be warned and given a sufficient time to indicate more time.
These 16 rules are well-developed by the US government and only ordered the Intranet and Internet Web site of the federal organization. However, in order to perform accessibility guidelines in ordering government agencies, the United States is not unique. There are also similar laws in Australia, Canada, France, Germany, Japan and the United Kingdom. For a list of visibility policies listed in the country, please visit WAI's Policies Relating to Web Accessibility page.
Check if it meets accessibility
By using free Bobby Online Portal, you can quickly determine if a given web page is in line with WCAG or Section 508. In this Web site, you can enter a URL of a web page, select Check, or comply with the WCAG or comply with Section 508, and then view reports listing compliance levels. Figure 1 shows a screenshot of Bobby Online Portal, showing a WCAG compliance test that will be executed on the Microsoft MSDN home page.
Figure 1. Bobby online portal
Figure 2 shows a screenshot of the MSDN homepage report. As you can see, the MSDN page does not meet any level of the WCAG accessibility criteria because it lost the alternative text of the image. As shown in Figure 2, there are five conflicts of 5 priority 2 and 4 priority 3 conflicts. Figure 2. Accessibility of evaluating MSDN pages
For the visibility guidelines that determine if your Web site meets WCAG or Section 508, Bobby is a good tool. Unfortunately, Bobby can only handle one URL each time, only one query is permitted every minute. However, there is a commercial product available to test whether the entire Web site meets accessibility and does not limit only a certain number of queries per minute. More information about these commercial products can be found on the Bobby online portal site.
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Microsoft easy access to ASP.NET 1.x is easy to access ASP.NET web control
Many WCAG Checkpoints and Section 508 Rules stipulate that the specified HTML tag should make Web sites easier access. For example, checkpoints in WCAG 5.1 (a priority 1 checkpoint) and rule (7) in Section 508 require
| and not.) However, in 2003 6 Month, Microsoft released ASP.NET HotFix Rollup Package, compared to other packages, which included a DataGRID that complies with Rule (7) in Section 508.
Note ASP.NET HotFix Rollup package provides additional enhancements related to accessibility. For example, it adds an optional AssociatedControlID property to the Label Web control to specify the ID of the web control associated with the Label. If this property is provided, Label will be rendered as the Back to top Create an adaptive, easy access to DataGrid web control The web control provided in the hot repair program released in June 2003, promoting the ASP.NET Web control to the standard of Section 508. However, even if there is a hot repair program, there is still a checkpoint of many WCAG priority 1. Fortunately, you can easily extend the functionality of the existing web control to meet your company's request for accessibility guidelines. This may be due to the role of inheritance. In particular, we can use web controls that do not meet accessibility standards and create a standard extension web control. By using inheritance, we only need to change or add functions to comply with standards without having to rewrite basic functions. Wring in WCAG Checkpoint 6.3: "Make sure the page can still be used when the script, applet, or other programming object is turned off or not supported. If you can't do this, you can provide equivalent on an alternative accessible page. Information. For example, when the script is turned off or not supported, make sure that the linked link is normal (such as: Do not use "JavaScript:" as a link target). "However, the LinkButton Web control is as a JavaScript: link Target ( ... ) hyperlink is presented. The problem is that a browser that does not support JavaScript cannot return to the web page by clicking the LinkButton. In a browser that does not support JavaScript, this makes sorted DataGrid rendered in orderless, because the column header is rendered as a linkbutton The remainder of this article focus on building a set of adaptive custom DataGrid columns, if you do not support JavaScript, you will display a Button web control in the tabs of the canable DataGrid. Because the Button web control presents tag rather than the JavaScript: The hyperlink of the link target, it can be used to not support JavaScript browsers. Note The section 508 requires a link to use the JavaScript: link target. The unique comment for the client script in Section 508 can be found in the rule (12), which is written in: "The page uses the scripting language to display the content, or create an interface element, the information provided by the script should be used by secondary technology. The function text is identified. "This rule requires that if the content is generated by script, or if a page is modified by script, you should use a & lt; script> html element with explanation script behavior. In any case, I listen to some developers engaged in government projects, or ask them to support browsers without JavaScript feature. Make DataGridColumn adaptable The DataGrid Web control consists of many columns, which are classes derived from the System.Web.ui.WebControls.DataGridColumn class. ASP.NET comes with 5 built-in DataGrid column types: 1. BOUNDCOLUMN 2. ButtonColumn 3. EditcommandColumn 4. HyperLinkColumn 5. TemplateColumn Base class DataGridColumn provides intrinsic and methods inherent in all DataGrid column types. This includes such as Headertext, sortexpression¡¡. ¢ Visible and other properties. When creating a DataGrid, there are two ways to play an important role in the DataGridColumn class: • Initialize () - Initialization DataGridColumn¡ £ Turn once in the data binding process of DataGrid. • Initializecell (Cell, Index, ItemType) - During the data binding process of DataGrid, for each cell created for each column. Cell is a Tablecell object that represents the actual HTML |
