What are the differences between User Control and Custom Control in ASP.NET
AFAIK, user controls are controls that you can create out of existing controls and can be part of the project and have a designer surface for you to drag/drop.
Custom controls are generally external to the project & would require to be hand-coded (using various asp.net control events & html building in the code).
User Controls are inherit from UserControl class by system default and can combine controls in terms of specific UI case and can have UI logic as well and reuse again and again anywhere within project.
Custom Controls are inherits from Control class (that you can change any control type what you want to customize) and generally use to add extra ability to an existing UI controls.
Difference between CustomControl and UserControl
So, now you got the difference between Custom Control and User Control, I guess. Let's summarize the difference again. Read the comparison below to make it clear:
Related
Could any give me a best Custom control application with code snippet and explain me the basic difference between Custom control and user control?
Thanks in advance ,
Laxmi
User Control is collection or grouping of WebControls. It is similar to aspx page and is used to place common markup code in a common file.
Refer Web Forms User Controls to create user control, convert page to user control, consume user control, e.t.c
Custom Control Inherits from WebControl to achieve some extra functionality. These are classes.
Sample Custom Control
public class DropdownListExtended : DropdownList
{
// My custom logic
// ususaly an event is overriden by developers to achieve extra functionality
}
Webcontrols:- are TextBox, Label, DropdownList, e.t.c
Hopefully your understanding are builds.
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.
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.
I have read over this which sort of gives an explanation of when you'd choose Web Control vs. Control when creating custom controls but it's not quite enough. I've seen custom controls inherit from either when they're both rending out stuff to the UI.
http://msdn.microsoft.com/en-us/library/yhzc935f.aspx
"If your control renders a user interface (UI) element or any other visible element on the client, you should derive your control from System.Web.UI.WebControls..::.WebControl (or a derived class). If your control renders an element that is not visible in the browser, such as a hidden element or a meta element, derive your control from System.Web.UI..::.Control. The WebControl class derives from Control and adds style-related properties such as Font, ForeColor, and BackColor. In addition, a control that derives from WebControl participates in the themes features of ASP.NET without any extra work on your part. "
so the only reason to use WebControl is if you want to use their styling features? I'm just going to output strings with a stringbuilder utlimately so I don't care about that stuff. I'd prefer to use straight up tableless design and strings to form my HTML that my control renders anyway.
Control
Deriving from the Control class allows our control to take advantage of the rendering methods provided by the Control class, as well as the use of ViewState.
WebControl
The WebControl class derives from the Control class. However, if we derive our custom control from WebControl, we get free support for many visual aspects of our control, like font size, CSS classes, background colour and so on.
Which class should I derive from?
When you are creating a custom control that requires little or no UI, then you should derive from the Control class. If your control does require the need for extensive UI support, then you should derive from WebControl.
From: http://dotnetslackers.com/articles/aspnet/ASPNETCustomControlsPart1.aspx
WebControl doesn't render tables or anything like that unless you tell it to. What it does have is the styling features that most users will expect from a control that renders with a UI.
It doesn't cost you much to use it. Give it a try and see if it causes you any problems.
So, do you have a question to ask? I think the differences between the two were well addressed in the MSDN article.
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.