What is the difference, what is the official terms, are any terms obsolete in ASP.NET 3.5?
UserControl: A custom control, ending in .ascx, that is composed of other web controls. Its almost like a small version of an aspx webpage. It consists of a UI (the ascx) and codebehind. Cannot be reused in other projects by referencing a DLL.
WebControl: A control hosted on a webpage or in a UserControl. It consists of one or more classes, working in tandem, and is hosted on an aspx page or in a UserControl. WebControls don't have a UI "page" and must render their content directly. They can be reused in other applications by referencing their DLLs.
RenderedControl: Does not exist. May be synonymous to WebControl. Might indicate the control is written directly to the HttpResponse rather than rendered to an aspx page.
CompositeControl: Inbetween UserControls and WebControls. They code like UserControls, as they are composed of other controls. There is not any graphical UI for control compositing, and support for UI editing of CompositeControls must be coded by the control designer. Compositing is done in the codebehind. CompositeControls can be reused in other projects like WebControls.
You've forgotten the ServerControl.
In my understanding it is like that:
There are only two different kind of controls: UserControl and ServerControl
CompositeControls are kind of "advanced" UserControls. Find some more info on Scott Guthries Blog.
All of them are WebControls (because they are all derived from System.Web.UI.Control)
They are all rendered in any way so i would like to see them all as rendered controls.
From MSDN:
User Control
In ASP.NET: A server
control that is authored declaratively
using the same syntax as an ASP.NET
page and is saved as a text file with
an .ascx extension. User controls
allow page functionality to be
partitioned and reused. Upon first
request, the page framework parses a
user control into a class that derives
from System.Web.UI.UserControl and
compiles that class into an assembly,
which it reuses on subsequent
requests. User controls are easy to
develop due to their page-style
authoring and deployment without prior
compilation.
Server control
A server-side component
that encapsulates user interface and
related functionality. An ASP.NET
server control derives directly or
indirectly from the
System.Web.UI.Control class. The
superset of ASP.NET server controls
includes Web server controls, HTML
server controls, and ASP.NET mobile
controls. The page syntax for an
ASP.NET server control includes a
runat="server" attribute on the
control's tag. See also: HTML server
control, validation server controls,
Web server control.
Like Web Forms, user controls can be created in the visual designer or they can be written with code separate from the HTML. They can also support execution events. However, since Web user controls are compiled dynamically at run time they cannot be added to the Toolbox and they are represented by a simple placeholder when added to a page.
This makes Web user controls harder to use if you are accustomed to full Visual Studio .NET design-time support, including the Properties window and Design view previews. Also the only way to share the user control between applications is to put a separate copy in each application, which takes more maintenance if you make changes to the control.
Web custom controls are compiled code, which makes them easier to use but more difficult to create. Web custom controls must be authored in code. Once you have created the control you can add it to the Toolbox and display it in a visual designer with full Properties window support and all the other design-time features of ASP.NET server controls. In addition you can install a single copy of the Web custom control in the global assembly cache and share it between applications, which make maintenance easier.
Contrary to Will's response, it is possible to reuse UserControls in other projects by referencing a web deployment project.
Since I don't have enough reputation yet to comment, I'll add this as an answer, but it refers to Will's answer above.
From the link you included:
Composite controls are the right tool to architect complex components in which multiple child controls are aggregated and interact among themselves and with the outside world. Rendered controls are just right for read-only aggregation of controls in which the output doesn't include interactive elements such as drop-down or text boxes.
I believe the documentation is refering to UserControls that have been created by overriding the Render method as Rendered Controls. Thus, it is not a separate type as the question implies, but a way of implementing a UserControl; a pattern.
Related
I am having a hard time finding a good answer for this question, but what is the difference between a static and a dynamic control in an ASP.NET webforms application.
Does having a dropdown list declared in html, but databound in code behind deem it a dynamic or static control?
Web Form has only 3 kind of controls - Server Control, User Control and Custom Server Control.
You can use all three types of controls in following two scenarios -
Static - You add a control inside ASPX at compile time.
Dynamic - You render a control from code behind at run time. It is not easy especially if you are new to Web Form.
Does having a dropdown list declared in html, but databound in code
behind deem it a dynamic or static control?
It is a static way of using a control, since you declare the control inside ASPX at compile time.
I've created a set of user controls in vb.net and in their original project they work fine.
I've since created a user control library dll and I wish to use it in a new project.
I add the reference to the dll fine, specify the tag library in an asp.net page fine and define controls on the page fine.
Everything seems to work except I get no rendered output.
Various properies of the controls and the page_load methods are all called.
Asp.net trace shows the controls in the page hierarchy etc
Just no output where the controls should be - any suggestions?
Update 1
I just compared a trace of the working output compared to the non working.
The working output contains the user controls (and all elements in them)
The non working output only lists the user controls - no content
It therefore seems that the content of the controls is missing somehow - as if the markup is not being compiled with the codebehind, only the codebehind seems to be working.
Update 2
The controls are inheriting from UserControl not control.
You are correct in your summarization in Update 1- your markup has not been included!
You need to provide a bit of elbow grease if your trying to distribute .ascx controls in a .dll but not too much thankfully.
The two main things you need to do:
Embedded your .ascx controls. The .ascx controls need to be marked as an embedded resource in your .dll (as oppossed to 'content')
Create a VirtualPathProvider. This will allow you to load the ascx files directly from the dll they are embedded in.
Unfortunately explaining step 2 is slightly lengthy, however this excellent article helped me out in doing exactly what you want to do.
The beauty of distributing .ascx controls like this is that you dont have to tear your hair out writing custom controls (rendering anything over than very simple html is a nightmare to make sense of).
I assume that you are not confusing between user control (.ascx) and custom controls. For user controls to work, one needs both ascx (mark-up file) along with corresponding code-behind class. User control are typically consists of constituent child controls whose hierarchy is specified within ascx file that provides some UI. In a class library (dll) project, you cannot package ascx files - all you get is the code-behind class. Without ascx, the code-behind class will not have any child controls and hence will render empty. In short, you cannot package user controls (ascx) in a class library - you have to add them into your actual web project.
For shared control, one has to use custom controls. Custom controls are code-only and typically provides render override that emits necessary html (or creates the own child control tree dynamically). These controls can be package as a class library and shared across project. Typically, a custom control will also have other helper classes to provide design time assistance (UI Editors etc).
why should be used use control template in asp.net? please, someone say me.
Can anyone tell me why I should use a Control Template over a UserControl in ASP.Net?
If you're familiar with MVC, a User Control is like the WebForms equivalent of a partial view.
Update (when I answered, the question asked when to use a User Control...):
A server control is appropriate when you want to bundle assets and functionality for wider distribution than a single project. It is more complex to develop a server control than it is a User Control, but a server-control allows you to completely encapsulate HTML, CSS, JavaScript, images, and server-side logic within a single DLL.
Conversely, a User Control is much easier to develop, but cannot contain assets such as external CSS/JS or images. User Controls are basically just partial bits of an ASPX page.
Unless you know that you need the features of a server control, I would always recommend a User Control for simple de-duplication of content that's repeated in multiple ASPX pages.
A User Control enables you to create your own custom control modules. They're useful because they are reusable, meaning you don't have to duplicate a lot of code. You can embed them in ASP.net pages, and you can define methods and properties for them.
We are plannning to use Ajax in our ASP.net project. However, we still want the member panel of our web site to work in all browsers. We have decided not to use Ajax in some forms where browser independence is must.
I am now confused with whether we should use ASP.NET controls or HTML controls or both?
I have two questions:
Are there any problems that I might face using either of approach?
Also which one is better considering efficiency and performance?
The Asp.Net Controls including the ajax controls are independent of browsers, asp.net will detect your browser and try to render the best html/javascript for that browser. So you are good with server controls.
If you are going to implement the project in asp.net then for all the controls that need to be accessed via code at server side needs to be asp.net controls. Those controls that are static and only displaying some value can be html controls.
The main point is that the asp.net controls are rendered to html controls... so the client who views the web-page actually gets the html controls.
For AJAX refer this
ASP controls and HTML controls as complementary.
ASP controls bring facilities for programming like the viewstate (the control keeps its content after a post back), the binding with datatable, and a lot of presentation properties. It is really an advantage in terms of time and maintainability to use these controls. They also manage some security feature like html code injection. ASP controls could be controled and managed from the code behind page.
HTML controls are out of the native ASP.NET page process. It is sometime a good thing to have particular control that you don't want ASP.NET take in charge and modify, but it is not the core of an ASP.NET web application.
If you can use HTML - it is always better - as it is much faster.
The use of ASP controls should work on all browsers as far as I know, but it less efficient.
Better create a small example and test it on some browsers before you decide.
(I've used ajax on both explorer and Firefox and it works)
If they are different, under what circumstances should we decide to use either approach?
Also, what is the advantage of ascx over aspx?
user controls are a form of custom control, that gives you a visual designer. They are ideal for use when you want a reusable control within the same web site. (It is possible to create and package user controls as seperate assemblies but that is beyond the scope of this question and I know has been asked on SO).
A custom control is typically used to refer to a Web Control, or a Composite Control which is specialized form of a web control. These controls have no designer and are usually implemented in seperate projects from your web allowing them to be reused accross many sites.
Now your second question, ASCX and ASPX are two different things. ASCX is the extension for a User Control, where as ASPX is an ASP.Net Page. You cannot use an ASCX by itself it must be placed onto an ASPX or Master page.
One way I like to use user controls is I have for example a very complex page which have 7 tabs, 5 of those have grids, of those grids three of them are identicle. Well what I can do is create a seperate user control for the content of the tabs, this now reduces the code I need down significantly (Since three grids are identicle except for the data).
Further more it allows multiple to work on various parts of the page, and it helps me keep everything straight since I am reducing the complexity of the page. You do not use User Controls instead of Pages, you use them in conjuction with a page.
Edit
You do not use ascx over aspx. You use ascx to complement. For example on my site every page has the same footer, but I don't want every page to derive from a single master page. I can create my footer as an acsx control and put it in each of my master pages.
Another example, I have a form that lets a user enter three different date ranges. (And we have other forms). So I put the logic to enable a calender button, and a text box that when clicked on opens up the calender, in a user control. I can then reuse that user control in all my aspx pages.
Custom controls are control build entirely in code. The pro is that you can put them in libreries, add an icon to the toolbox and other fine control.
User controls are more easy to do, and in general is a way to encapsulate things to simplify other pages or when you need to use the same markup in several pages.
The advantage of controls over regular aspx pages is that you only need to do some part of the markup (not the whole page)
User Controls/Composite controls
User controls that are made up of other ASP.Net or custom controls. They are usually quite straight forward and can be created quite quickly. They Are generally not shared across projects however there are some tricks that can allow you to do this.
Custom controls
Custom controls are controls that you implement the UI by creating everything from the HTML output to design time support. Custom controls take much longer to make. You must use either Web.UI.Control or inherit from a sub control (Textbox for example). Custom controls are compiled to binary format to allow them to be distributed more easily. Since they are compiled they can be referenced from the toolbox in visual studio.
There are 2 main advantages to using a control in an aspx page. Encapsulation of logic and reuseability.