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ASP.NET User Controls. Make your own controls by grouping other controls. What is a User Control?. A user controls is a grouping of other server controls into a single-container control User controls are composite A user control contains child controls. How to create a User Control?.
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ASP.NET User Controls Make your own controls by grouping other controls ASP.NET User Controls
What is a User Control? • A user controls is a grouping of other server controls into a single-container control • User controls are composite • A user control contains child controls ASP.NET User Controls
How to create a User Control? • Make a new folder ”Controls” • Create a New Item -> User Control • Filename.ascx • User controls are designer friendly • You can drag-and-drop child controls from the Visual Studio Toolbox to the control ASP.NET User Controls
When to create a User Control? • A User Control is useful, if you have a set of controls that appears on many pages. • You aggregate the individual controls in a new user control • The user control can then be used in a number of pages ASP.NET User Controls
Using a user control • Using a User Controls is like using any other server control • User controls can be used wherever you can user other kinds of controls, like • Web forms • Master pages • Other (bigger) user controls • User control must be registered • Register in single page <%@register ….%> • Register in web.xml ASP.NET User Controls
User control registration • To use a User Control the User Control must be registered. • Registration can be done in two places • In the file using the User Control • <%@ Register src="/Controls/Banner.ascx" tagname="Banner" tagprefix="uc1" %> • <uc1:Banner ID="Banner1" runat="server" DisplayDirection="Horizontal" /> • In web.xml • Site-Wide registration ASP.NET User Controls
Site-Wide registration of user controlsin web.config <configuration> … <system.web> <pages> <controls> <add tagPrefix="mine" tagName="Banner" src="/Controls/Banner.ascx"/> </controls> </pages> … <system.web> <configuration> ASP.NET User Controls
User Control Properties • User Controls can have properties • Properties are declared in the code-behind of the user control • Set in the page that uses the User Control • Declaratively from the page using the User Control • Programmatically from the code-behind of the page using the User Control • Get the value in the code-behind ASP.NET User Controls
User control events • User controls can have events • Just like ordinary controls • Example: Events from sub-controls can be propagated to the user control • Called ”Event Bubbling” • Event arguments can be empty, or carry data. • Example: usercontrol/loginusercontrol ASP.NET User Controls
Best practices • Don’t overuse user controls • User controls encapsulate repeating content • UI + code spread over more files • A user controls should focus on a single task • Don’t hardcode style info (CSS) in a user control • Make a CssClass property for the user control ASP.NET User Controls
Further reading, etc. • Imar SpaanjaarsBeginning ASP.NET 4 in C# and VB, Wrox 2010 • Chapter 8 User Controls, page 271-296 • ASP.NET - 10 - User controls (video 1:19 min) • http://www.youtube.com/watch?v=NDWLtFvqQaY • http://www.5min.com/Video/How-to-Use-ASPNET---Tutorial-10---User-Controls-63590289 • Chris Peels Create a Custom User Control in ASP.NET (video 27 min, VB), 2007 • http://www.asp.net/general/videos/how-do-i-create-a-custom-user-control-in-aspnet • Bill Evjen et al. Professional ASP.NET 4 in C# and VB, Wrox 2010 • Chapter 25 User and Server Controls, page 979-987 • George Shepherd Microsoft ASP.NET 4 Step by Step, Microsoft Press 2010 • Chapter 5 Composite Controls, page 110-117 ASP.NET User Controls