Controlling HTML in ASP. NET Web. Forms. Resources Mentioned in the Show. Developers want control. Developing for the web is seemingly. Sometimes our. tools and frameworks give us power, but not control. While we love the functionality. ASP. NET Web. Forms. HTML isn. MVC and control adapters are not the only answer to gaining. For the sea of standard Web. Form applications there are many techniques. Tame View. State. One of the first places to exercise control over your HTML. View. State. View. State was once hailed as a huge time saver upon. ASP. NET is maligned for. The fact is, though, View. State is not inherently evil and is. I have a GridView where a user can enter information in the. Where @User is controlled by the InsertParameter. Using these items when creating custom context menus gives an. Controlling HTML in ASP.NET WebForms - download -. Improve ListView and GridView performance and startup time through UI virtualization, element reduction, and progressive updating of items. Focus in GridView layout. Because program focused the grid field and not the. The problem with ASP. NET is not that it. View. State, but that the framework is cavalier in its use of View. State. The page template and all controls automatically. View. State enabled. The following is a screen shot of the HTML generated by the. List. View: Notice that the control simply renders a table. There is no. editing behavior implemented on this page therefore there is no need for. View. State. Disabling View. State will change the source to look like this: Note: Surprisingly. Enable. View. State=. If you. have a HTML form set to run- at server, then you will always have at least one. This data, though, is. Tip: Turn off. View. State by default and use it only when necessary. You can even turn off. View. State globally in your application by disabling it in the web. If you find View. State is unavoidable in your application you may consider looking. Question the Form Tag. Another foundational control in ASP. NET is the run- at server. As you just saw when working with View. State, as long as a. HTML in the form of. View. State and supporting Java. Script for post backs is emitted to the page. The. default ASP. NET page template includes a form tag on every page, but often its. Returning to the example from the previous section, look at. HTML generated from placing a read- only List. View in a server form with. View. State disabled: This page has no input controls and is simply a read- only. You may even consider removing them from your page first and. Perhaps. you are even so bold as to edit the Visual Studio template to remove the form. The template is found under this location: C: \Program Files\Microsoft Visual Studio. Web\Web. New. File. Items\CSharp\Web. Form. aspxor. C: \Program Files\Microsoft Visual Studio. Web\Web. New. File. Items\VB\Web. Form. NOTE: If you edit. Visual Studio. The change suggested here, however. In any event make backups - be certain of what you are doing. This abstraction determines how controls. While these benefits are realized in many situations. I have often seen developers use inappropriate controls just. The Literal Control. Do you need to render. The resulting HTML from each of these controls is quite. The Label is rendered with wrapping SPAN tags. In this case. the control is on a page associated to a master page so the HTML bloats even. ID generated by the server. Often when using a. Label control developers do not use the accompanying HTML that. The Placeholder Control. Do you need to. programmatically show or hide a group of controls? What makes the Placeholder useful is that the control may contain. HTML to the page. Often Placeholders are used for template designs and other scenarios. There are a. number of other applications for the Placeholder beyond its normal use. You can. also use this control to help control what is shown and hidden on your page. Consider the typical scenario where a message is initially. A common approach. DIV on the page and set the. Visiblity property to false: For simple pages the markup that is rendered to the page is. HTML gets. altered. The next screenshot shows you how that DIV is rendered to. The age- old problem of ASP. NET changing a control. This is a problem because once you start interacting with style. Java. Script the client IDs become very important. While there are a. CSS and scripting, why not dodge the. Instead of making the DIV a server control, wrap your. Placeholder and then you have the same programmatic control. HTML being. affected. You could also use the Multi. View. control to accomplish this same behavior without generating any extra. Tip: Use controls. HTML wherever appropriate. Expressions Have No Ego. If you truly don. ASP. NET MVC makes heavy use of expressions and while some think. Getting data into the control requires you to. Writing code is not a bad practice at all . Depending on where the control resides on the page. Declaring a control in the. ASPXFinding the appropriate. Locating and cast the. Provide the control with. If you opt for using expressions instead you can simply. So instead of doing this: Try doing this: In the end you. The following. tables contain an abbreviated list of ASP. NET server controls and a summary of. Standard Controls. Control Name. Renders. Label. SPAN elements surrounding Text property value. Text. Box. HTML text input element. Button. HTML button input element. Link. Button. Anchor element. Image. Button. Anchor and image (IMG) elements. Hyper. Link. Anchor element. Drop. Down. List. Select element with options for values. List. Box. Select element with option tags for values. In some arenas. ASP. NET is viewed as a sub- standard platform for creating search engine. While this charge is categorically false, sometimes it. While Microsoft and a host of third- party organizations. RAD development, using these. The bottom line is know the HTML you are generating and use.
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