I inherited a project that uses a RadioButtonList which inherits from a ListBox. It was taken off the web (currently cannot find a link to), and contains RadioButtonList.cs (which contains six dependency properties) and RadioButtonList.xaml (which is just styles and control templates).
This control is used in over a hundred places. It causes problems because it is not a complete and professional control. Problems such as, focus issues, keyboard navigation, and so on. (See comments.)
After much research at different times over the last couple years, it seems that this control is really not necessary. All that is needed is to set the GroupName property on a group of radio-buttons. And, the only reason why a RadioButtonList control is used is to help with data-binding a list of options through the inherited ListBox.
1) Is this control really necessary? Is there a better way?
2) Is there a professional control, open-source or otherwise, that will allow me to get the benefits of data-binding without the headaches? (We use Infragistics and DevExpress, but I am not familiar with all the controls these suites offer.)
My Answers
1a) Is this control really necessary?
If you only need one list of radio buttons, then no this control is not necessary.
If your applicaton uses many lists of radio buttons, then yes this control is necessary.
If you use a list of radio buttons in different applications, then yes this control is probably necessary.
1b) Is there a better way?
I say that deriving from a ListBox, ItemsControl, or whatever then creating styles and templates is the only way to create this control; therefore, no there is no better way.
2) Is there a professional control...
Definitely, the ListBoxEdit with the RadioListBoxEditStyleSettings.
Comments Regarding Answers
All the answers indicate that creating a RadioButtonList control is not necessary. Yet, if you need more than a couple lists of radio buttons, by the time you create the styles and control templates and maybe data template, you will end up with a collection of code artifacts that can be called a radio-button-list-control. Therefore, in my opinion, a RadioButtonList is necessary.
Moreover, my understanding is a RadioButtonList was dropped in an early WPF CTP. Which I can understand, because of the limited need for such a control that can easily be created.
Comment Regarding Accepted Answer
2) Is there a professional control...
Definitely, the ListBoxEdit with the RadioListBoxEditStyleSettings.
Lastly Comment on Mike Strobel's Answer
The RadioButtonList that I have is the end-result of his answer. While I am good at creating custom-controls, I rather let third-party component makers, such as Infragistics and DevExpress, create and support a basic control like this one.
Is this control really necessary? Is there a better way?
As #lawc points out, no, it is not necessary. It may, however, be preferable, depending on what level of flexibility you desire. A reusable style is easy enough to create, but doing it "correctly" is a bit more involved than simply setting a custom ItemTemplate.
Using Styles
An ItemsControl in WPF will wrap its items in appropriate containers. Each of the selector controls in core WPF overrides the logic which determines whether an item is capable of serving as its own container, as well as the factory code which produces new item containers. A ListBox, for example, will wrap each of its items in a ListBoxItem (unless the item itself is already a ListBoxItem). The style applied to these containers can be set for the parent ItemsControl via the ItemContainerStyle property. This differs from the ItemTemplate property, which allows you to control the appearance of the item within the container. More specifically, it overrides the content template applied to the ContentPresenter within the container.
Since a RadioButton does not derive from ListBoxItem, simply setting the ItemTemplate will produce a list of RadioButton controls embedded within ListBoxItem controls, which means they will still have the same selection chrome normally associated with ListBox controls, and possibly some layout and focus oddities. This is probably not what you want.
Instead, override the ItemContainerStyle and use it to assign a custom ListBoxItem template which embeds a RadioButton. You can probably get away with not setting the GroupName property at all, which eliminates possible name collisions. Instead, just establish a two-way binding between the RadioButton.IsChecked property and the templated parent's ListBoxItem.IsSelected property.
In order to use this technique conveniently, one generally creates a Style resource (available application-wide) which can be applied to the appropriate ListBox instances, and which sets the ItemContainerStyle. Alternatively, you can make the container style available as a global resource and set that on your ListBox instances. Either way, you need to set a property.
Using a Custom Control
While WPF evangelists often recite the philosophy of preferring custom styles over custom controls, in practice this is not always convenient. You may find it more convenient to create a RadioButtonList which extends the ListBox control, and then give it a default style which automatically applies the custom style described above. This gets you out of manually assigning the list style or container style on every ListBox instance, but it's not a huge win.
But maybe you want a bit more control over the appearance of the RadioButton items. For instance, you may want to:
Adjust the margin around the "bullet" of each RadioButton item;
Adjust the vertical alignment of the bullets relative to the content;
Support both horizontal and vertical orientations;
Automatically disable the RadioButton content for items which are not selected.
Creating your own implementation, most likely derived from ListBox, allows you to add these features easily, even after you are already using your radio list across your application. This could be done with the technique above too, though it may require an attached behavior or some attached properties, in which case you end up with a somewhat fragmented design.
Third-Party Solutions
Is there a professional control, open-source or otherwise, that will allow me to get the benefits of data-binding without the headaches?
This is not an uncommon use case, and I have no doubt there are some implementations floating around. Some may be in open source frameworks, and some may be extracted from open source applications. As for third-party implementations, I do know that Actipro ships a RadioButtonList in their Shared WPF library, which is included with all of their WPF components. When last I checked, it was not available on its own. It does, however, support all of the additional features I listed above.
I can only tell you that DevExpress uses a ListBoxEdit with a RadioListBoxEditStyleSettings to represent a group of RadioButtons. Practically it is the same as your control you are using, but i think it provides better functionality and is well tested. A RadioButton is not provided by DevExpress and in my application i use the Default RadionButton-Control provided by WPF/Silverlight.
You use the RadioListBoxEdit of DevExpress as follows:
<dxe:ListBoxEdit SelectedItem={Binding CheckItem, Mode=TwoWay}>
<dxe:ListBoxEdit.StyleSettings>
<dxe:RadioListBoxEditStyleSettings />
</dxe:ListBoxEdit.StyleSettings>
</dxe:ListBoxEdit>
More information about the ListBoxEdit of DevExpress can be found here
In my opinion you don't need this control.
You can simply use .Net ListBox to achieve all your existing functionality.
Using ListBox.ItemsSource you can data bind your options collection
Specify ListBox.ItemTemplate containing the RadioButton, in this template you can data bind your view model property to RadioButton.GroupName
IMHO, a control deriving from ItemsControl would be the cleanest approach.
Then you probably would override
IsItemItsOwnContainerOverride() with return item is RadioButton;
GetContainerForItemOverride() to return a new RadioButton() for each item and
PrepareContainerForItemOverride() to set up binding of ToggleButton.IsCheckedProperty and ContentControl.ContentProperty.
While these parts are just boilerplate code, some more efforts may lie in the implementation of the keyboard behavior.
So much reading, and so much about inheritance, I can't find any direct answers, so here goes.
If you have a base-class derived to do certain things, look or act a certain way, you can subclass it and get all the functionality of the parent class with only slightly modified differential. The same does not appear to be the same for working with WPF Themes... more specifically, the combobox control (similar issues with textbox, but that's obviously less complex).
By looking at the Control Template Examples, they discuss the entire structure of it, the borders, backgrounds, glyphs, actions, properties, etc.
If the ONLY thing I want to do with a combobox is to change the border of it to Red if there is an error in it, it appears, I have to basically redefine the entire thing and somehow put in my custom trigger setting / color to be implemented.
Somewhat similar is that of the textbox control and how its created. It has the named control when trying to nuts around with the background color... you can't just say... background = some static brush value.
What shortcuts are out there to only allow overriding these small elements without having to re-create the entire template control. I can just imagine what would go on with grids, tabbed controls, and others that could get extremely messed up if you miss one simple thing.
I also see that some controls are made up of OTHER Control.Templates, so how might I be able to attach to changing the property setting on just the single element of the control template... Such as the combobox has the control template for the Toggle Button. From that, it has a border via x:Name="Border" and I want to change THAT element within a derived style.
Thanks
I might not understand your question here. But from what i get is:
Yes you can't partially implement Templates, in fact i wouldn't know how this could be possible. But, if you want to change certain things, you can of course do that. You can create Styles, Templates, Brushes etc. as DependencyProperties and use TemplateBinding to bind to them, on the given child control.
Remember that WPF allows always to change the template on the fly. if we could partially change the template this would might hurt performance or could get messy and complicated. Still, you can do that using ContentControls and TemplateBinding or simply Triggers.
For my custom controls, which might contain multiple part sub controls, i usually add a style for them. For example, a custom ComboBox would contain a ToggleButtonStyle.
One thing that would be nice though, would be to add control template triggers without the need to reimplement the template.
I am trying to work though the best approach to accomplish the following. Within a page I have it divided into two section. On the left a listbox and the right is empty. (Grid etc). What I would like to accomplish is when an item is selected from the listbox a different user control loads in the right panel. For example if I have three items (one, two three) selecting one would load a red user control, two would load a blue user control and three a green user control.
I was taking this approach since Content Template / Data template selectors are not available in SL. However if anyone has another suggestion I would be grateful for your thoughts.
I'm creating this with MVVM in mind and traditionally I have managed this within the code behind of the user control however I have seen mention of how this could be managed within the ViewModel as well.
Any suggestions or guidance on a best approach is always appreciated.
Cheers
You can bind both listbox selected item and user control visibility properties to the same property in the viewModel.
Then just use a valueConverter for each user control to switch on/off the visibility.
Please tell me if i should elaborate/add a code sample.
Now I'm about to learn RoutedEvents. I understand bubbling and tunneling and all. But I have a little problem I'm not sure how to handle.
I've got a ItemsControl in my own defined UserControl ( inherits TabItem ). This itemsControl could be a ListBox or some selector not decided yet ( depends what is best with this solution ).
Now when one item there is selected ( Not sure yet what the best selection method would be, perhaps doubleclick ) I need to capture the event in the TabControl that holds my UserControl. Thankfully as my userControl is put into the XAML visualtree the bubbling event flows up and events can reach the TabControl. However I still have a few problems with implementing this.
1) Let's say I set it as MouseDoubleClick I don't wan't other DoubleClicks ( like in other tabs or outside the ItemsControlItems ). I guess you can always do a check where the events coming from to ensure it's the right one but I don't feel it's the right way and it could be asking for trouble.
2) If I set the event to SelectionChanged and the ItemsControl to ListBox I would have to ensure the ListBox itself doesn't handle it so it can reach the tabControl. How would I do that?
3) Same as 2) but the TabControl is a selector itself so it would raise it's own selectionchange events wouldn't it. how would that work. Would the handler grab both from the listbox and the TabControl?
4) Not sure what ItemsControl I should use. If i'm only using it to doubleclick the item and then handle the event wouldn't ListBox be too much. It has many effects that would be undisireable like selection and such. Is it better to define your own ItemsControl or maybe use ListBox and overwrite some of it's properties like selection ( how would one do that? )?
5) The source of the event would be the ItemsContainer but I wan't the item itself. There is a easy way to get access to it isn't there?
6) Let's say I put a button and in the DataTemplate I wan't to attach the ID of the object through the button and capture it where the button click is handled to identify what item it was. Is there a property do do that or would I have to define it myself?
7) Would the best course of action here maybe to create my own event?
Your take on this issue and comments on what process is best to take here is appriciated.
EDIT: Decided to add little bit more info as asked.
What I'm aiming for; when I start the program I have a TabControl with 1 tab in it. This tab is different from the rest of the tabs will be because it holds a list of objects (CompanyModel). This list is the ItemsControl I mention. When you press one company from this list a new tab is added with info about that company.
My solution was to create a TabItem collection as a source for the TabControl. Then I would define my 2 types of TabItems in a seperate XAML source file (not sure what to call it, basicly add new usercontrol). One is the initial where thhe list appears, the other one takes in a CompanyModel as a constructor parameter and shows info about that.
This works while I don't like the idea of defining the company list tabitem seperatly I can't define it under the tabcontrol because I can only have defined items or sourced, not both.
I've tried this idea by putting a button on the List DataTemplate that bubbles the Id of the company selected up to the TabControl, handling it there and adding a new TabItem with the CompanyModel. That was just a solution to try it and has problems like if I add anpther button to the CompanyTabs I would grab them aswell in the TabControl.
So my problem could be solved by finding a good way to bubble a event from the original listTab or If I would be able to define the tab in the same place as the TabControl.
I know that one other solution would to have the list seperate from the TabControl but others would like to see how this comes out and I would like to learn how I would do this.
please have a look in this blog, may be it will helps u.
http://blogs.u2u.be/diederik/post/2009/09/09/In-WPF-SelectionChanged-does-not-mean-that-the-selection-changed.aspx
I'm interested in customizing a 3rd party control, such as Telerik's RadGridView, as a standalone control, for example adding New Row and Delete Row buttons above the grid, yet still supporting XAML manipulation of the internals of the control by the window upon which my control exists (i.e. for the window to add its own style to a column of the grid).
Is there a way to add the buttons, etc. with templates? Styles?
My current "solution" is to inherit from the RadGridView, but I'm stuck on how to add the features I need.
Thanks!
My suggestion is to use composition over inheritance.
You can create your own control (UserControl should do the work). Then you can define the layout (may be in Grid panel): buttons on the top, RadGridView bellow them, etc. For custom column styling you can use DynamicResource trick. Set the styles of the columns you want to modified with DynamicResource. This way when the control is added to the logical(visual) tree; WPF will walk up the control tree and find appropriate resource. This way in each window/page resources you can define the different resource.
Another idea that come to my mind is that you can extract the buttons as a separate control. The only reference that they will need will be RadGridView and you can use binding with element name to provide it.
I would go the custom UserControl route instead of inheritance route. Styling and theming work strangely when you're dealing w/sub-classes. Unless you're planning on duplicating and modifying Telerik's ControlTemplates and DataTemplates, it can get pretty hairy.