These are three different things you can add to a project and I am not quite sure if I understand the difference. They all seem to for example show up in the component toolbox when working with a Form. What are some common usage scenarios for each of them? What is the difference?
The main difference between User Control, Custom Control and Component is that they inherit from different levels in the inheritance tree:
MyComponent
|-> Component
MyCustomControl
|-> Control
|-> Component
MyUserControl
|-> ContainerControl
|-> ScrollableControl
|-> Control
|-> Component
So, in short you get a different amount of pre-wired functionality with the different options.
When would you use the different options? (these are thoughts and opinions, not truths)
Create a component if you want to provide functionality without UI (such as Timer components, data sources, ...)
Create a custom control if you want to make a component where you have full control over its visual appearance, and you don't want any baggage of unnecessary functionality. Typical cases would be simple controls with limited functionality (such as a button)
Create a user control if you are going to combine existing controls into reusable building blocks (such as two lists with buttons where you can move items between the lists).
Adding to what Fredrik said, generally components and custom controls would be used when you plan on reusing them across projects. Use user controls when you would only be using it in one project.
I believe the last statement is not correct in my opinion .
I create user controls for many different reasons.
The main reason is so that if per say I design an interface of multiple controls
grouped together.
I first create a class library , then I add user controls to it .
Now if i need to change any part of the logic behind how the user control works I can very easily. Also this class library can be used multiple times.
Also within the same classy library I can have multiple classes that can be shared and used for any of my user controls.
This is the main reason I use user controls.
And if you make a change to your user control or class library .
once you build the job .
the dll will dynamically up date in the bin folder .
So if i am referencing this in another project
Those changes will also appear in new project .
Also it doesn't use the same paint routines as the form and anything you have loaded on the form.
So user controls gives us the ability to be very modular
And i Can have multiple user controls that share the basics classes of the class library ...
So a user control purpose is just not for one project . It has no limitations in that respect.
jeff
The main difference between them-
User Control is a page file with extension .ascx which can only be
used within a single application or project But custom controls are assemblies(dll files) that can be used in multiple applications.
Related
I've created a groupbox that is used to populate a list of files and their description. I've also written the code behind for properly adding the files. Is it possible to share the code behind and UI so that it can be used in other forms without having to rewrite the code? I know that you can create a base form, that contains the winforms control you want to share. That way you can have your new form you inherit from the base class. But I'm not looking to implement it this way.
YES, it can be. Create a User Control for your GroupBox and use the same in whichever form you want. User controls are meant for that purpose to increase code re-usability.
In case, you think the same GroupBox control can be used in other project as well then you should consider building it as Custom Control
In Windows Forms applications, controls in the System.Windows.Forms library have a property named Site.
What is this property’s job in Controls?
The Site property is inherited from Component, and is very much like the Parent property of a Control.
The main difference between Parent and Site is that the value of Parent can only be a Control, while Site can have a non-visual container assigned to it.
The Component base-class is used for those non-visual tools in the Winforms designer toolbox. For example the System.Windows.Forms.Timer which can be dragged onto a Form. The PropertyGrid can be used to set its properties and assign event-handlers, all from the designer without writing a line of code.
The idea behind the System.ComponentModel classes is to provide an API for Software libraries to take advantage of design-time capabilities of an IDE such as Visual Studio. It caters to RAD (Rapid Application Development) concepts where general-purpose or generic components would take advantage of the API. For example to expose extra information about a property in the bottom section of the property-grid, or even create complete custom editors.
If you want to dive deeper into the internals you could look at Programming with Components, or if you want a quick overview, I guess Class vs. Component vs. Control may be a good starting point.
Sites bind a Component to a Container and enable communication between them, as well as provide a way for the container to manage its components.
Sites can also serve as a repository for container-specific, per-component information, such as the component name. For more information about components, see Programming with Components.
Notes to Implementers
To be a site, a class must implement the ISite interface.
Reference:
https://msdn.microsoft.com/en-us/library/system.componentmodel.isite.aspx
ı have been serching this for a while but I couldn't come up with a conclusion. What is UserControl? For me we can do everything with creating new windows forms instead of User Control. I know there is a reason to use but it is not clear right now. If someone illuminates the mystery that would be great.
A user control is basically a grouping of other existing control, intended as a reusable component (i.e. composite control). If you need to place the same group of controls on different windows you'd rather group them in a user control, adding things like data validation for instance, and then reuse this control whenever you need it.
Here is some more reading.
UserControls allow you to reuse your code. For example if you need a small component that displays two values (code and description), with UserControls you can design it only one time and then reuse it in other forms.
Also, you can add your custom properties\methods to the UserControl; in this way you can define simple (or even more complex) functions associated to the GUI control.
Hope this helps.
imagine you have a GridView with some new methods you create, and which you want to use on several pages. There you go. A UserControl is useful. That's just one example
As the others have explained a UserControl groups 'real' Controls and the logic that makes them work together as one component.
Imagine an application where the user can decide wether it runs in MDI mode or with separate windows or with tabbed pages. You can add the UCs of your application to any of these easily.
Think of a MP3 player with various controls, buttons, labels and sliders and user drawn-gauges. If it's in a UC you can re-use it directly. If it is all on a window, how do you re-use it?
So UCs are about flexibilty and re-using visual components.
I am currently working with a 3rd party ActiveX Control (an editor for topographical data distributed by Cadcorp SIS). I have to do some fairly complex stuff with it in a VB.NET (framework 4) program and am finding that the API that comes with the control is quite limited.
As of now I have made a custom control which houses the control and acts as a wrapper for it to allow me to extend the API, which works fine, but What I would really like to do it give the control more events so that I can monitor what is going on with the data more closely.
I'm not sure how to go about doing this though...
I tried inheriting from the control and I can extend it just fine, but I can't figure out how to reuse it after that. Is there some way I can inherit the control and get it to appear in the toolbox so I can just drop it onto a form? Or do I have to load it programatically? If so, how can I do it?
Any pointers, examples, tutorials or alternative ideas as to how to do this kind of thing would be welcome.
If you are not seeing your control class in toolbox it doesn’t mean that you can’t use it just modify code from your form's designer to use your inherited class
Or
You can drag-and-drop your assembly (dll) from Windows Explorer to the
toolbox in VS.NET. Or you can right click on the toolbox in VS.NET and
choose Add/Remove items. Is this what you are looking for?
Also
<ToolBoxItem(True), ToolboxBitmap("MyNamespace.MyClass.bmp")> _
Public Class MyClass
This question already has answers here:
What is the difference between a User Control Library and a Custom Control Library?
(3 answers)
Closed 1 year ago.
I'm working on creating a date/time user control in WPF using C# 2008. My first user control. I'm also using Matthew MacDonald's book, "Pro WPF in C# 2008". In that book he strongly recommended creating a user control using the WPF Custom Control Library project template; so I followed his suggestion. I've finished writing the code which would go into what I think of as the code-behind file. Now I'm ready to write the XAML.
The only problem is, I just discovered there is no corresponding .xaml file? So, I don't get why using a WPF Custom Control Library project is better, or prefered, when writing a user control?
A user control and a custom control solve two distinctly different problems.
UserControls are meant to compose multiple WPF controls together, in order to make a set of functionality built out of other controls. This is often used to compose a portion of a window or screen in order to organize your development by allowing you to group multiple pieces of functionality into one "control". For example, if you wanted to make a control for editing a User which provided text boxes for first and last name, age, etc., a single UserControl could be dropped onto a Window and bound to a User instance to edit this. (In this case, you're using standard controls, such as TextBox, to "compose" a control for a more complex purpose.)
A CustomControl, however, is meant to be a new single control. This would typically be a replacement for a built-in control (which could not be redone via templating). I've found that the need for CustomControls is actually fairly rare in WPF, since the WPF templating options and attached properties allow you to do nearly anything with standard controls, once you learn them fully.
I would also add, if you're intending to inherit from your control, then using a usercontrol is will complicate matters. For example, if create a base usercontrol that has a layout defined in Xaml, WPF framework won't allow you to inherit this control and use Xaml to define the layout for the subclass. In dotnet 3.5 Xaml control can't inherit from another Xaml control