MSDN Magazine - March 2008 - (Page 111)

The Only Data-Binding Control You’ll Ever Need FRITZ ONION T he ASP.NET 3.5 release that accompanies Visual Studio® 2008 introduces a new data-binding control—the ListView. I know what you’re thinking: why do we need yet another data-bound control in ASP.NET? After all, we already have more than 10 controls to choose from when displaying collections of data, including the semi-retired DataGrid, the new and improved GridView, the ever-solid and simple Repeater, the unique and flexible DataList, the handy FormView and its somewhat redundant sibling the DetailsView. And of course there are the single-dimensional list controls BulletedList, ListBox, DropDownList, RadioButtonList and CheckBoxList. Well, the ListView can literally replace all other data-binding controls in ASP.NET. That’s right, every last one. You could literally eschew every other control in the above list in lieu of the ListView control. The ListView also makes several data-binding tasks much easier than they were with previous controls, including styling with CSS, flexible pagination, and the full complement of sorting, inserting, deleting, and updating features. Let me begin by describing the typical usage model of the ListView, and then I will progress through the features of the control, illustrating its flexibility and power. By the end of this column you should have enough information to decide how many databound controls to keep in your ASP.NET toolbox. The ListView is a template-driven control, meaning that it will not render anything by default—you must completely specify the HTML you want it to render in the form of templates. Like most template controls, the ItemTemplate is going to be the focus of most of your efforts, as that is where you place the HTML content that will be repeated for each row of the bound data set. What is new in the ListView—and what really sets it apart from other controls—is the introduction of a LayoutTemplate. The LayoutTemplate is where you define the top-level HTML to be output as part of the control rendering. If you want the ListView to render as a table, for example, you would include the top-level and perhaps elements in the LayoutTemplate, leaving the row and cell rendering to the ItemTemplate as shown in Figure 1 (in this case, bound to a data source exposing a simple table containing movie titles and release dates). Figure 2 shows the browser rendering. The association between the LayoutTemplate and the ItemTem- plate is made by the single server-side control in the LayoutTemplate with an ID set to itemPlaceholder. (You can change the ID string from its default with the ItemPlaceholderID property of the ListView.) In my first example, I used the technique of placing an Figure 1 Using LayoutTemplate and ItemTemplate ID Title Release Date ListView Basics Figure 2 The List Displayed in a Table march2008 111

Table of Contents Feed for the Digital Edition of MSDN Magazine - March 2008

MSDN Magazine - March 2008 Contents Toolbox CLR Inside Out Data Points Advanced Basics Office Space Introducing ASP.NET MVC Loosen Up CI Server Performance Office Development Test Run Security Briefs Extreme ASP.NET Foundations .NET Matters {End Bracket}

MSDN Magazine - March 2008

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