Controls
This chapter is from the book
This chapter is from the book
This chapter is from the book
Terms you'll need to understand:
- CSS (cascading style sheets)
- HTML controls
- HTML server controls
- Input validation
- Web server controls
Techniques you'll need to master:
- Adding controls to ASP.NET pages
- Customizing control appearance and behavior by setting properties
- Dynamically loading controls at runtime
- Using cascading style sheets to customize the look of a Web site
- Validating user input
Controls are the building blocks of a graphical user interface (GUI). Visual Studio .NET allows you to work with the following types of controls on Web Forms:
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HTML Controls—Traditional HTML elements displayed as controls.
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HTML Server Controls—HTML elements that can be programmed on the server, marked with the runat="server" attribute.
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Web Server Controls—These new controls are specifically designed to integrate well with the ASP.NET programming model. They support data binding and other advanced capabilities and might render as multiple HTML controls.
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Validation Controls—Validation Controls are Web server controls that contain logic to validate input in other server controls.
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Web User Controls and Web Custom Controls—These are two types of controls that you can create yourself. You can learn more about these controls in Chapter 8, "Creating and Managing Components and .NET Assemblies."
HTML Controls
HTML controls represent common HTML elements. You can access all the commonly used HTML controls through the HTML tab in the Visual Studio .NET Toolbox. You can drag these controls to a Web Form and set their properties in the Properties window.
Controls from the HTML tab of the Toolbox such as Text Field and Label are converted to their appropriate HTML equivalent such as <INPUT> and <DIV> elements, respectively, in the source code of the ASPX file. All the HTML controls are automatically placed inside an HTML <FORM> element. These controls are saved exactly as they'll appear when they're sent to the user's browser.
You probably won't make much use of HTML controls on ASP.NET Web forms. That's because there's no good way to programmatically interact with these controls from your Visual Basic .NET controls. ASP.NET provides two other sets of controls that are much better suited for server-side programming: HTML Server controls and Web Server controls.