BarComboBox selected item DataTemplate

Hi Matt,

If you are just looking for a basic non-editable drop-down list of colors, it might be easiest to do what we did with the Text Highlight color and Font color in the main Bars demo where you have a split button (or could easily use a popup button instead) and have a color gallery one that.  Those examples show how we update the button's icon to render the color used.

Or alternatively, if you do want to use BarComboBox, you can do that as well.  BarComboBox is a gallery itself (which is why you need gallery items with it) and is intended mostly for text display in the selection box, but it can show an inline icon too.  Our "Combobox and Editors" sample has a "Categorized combobox usage" example where one of the entries there shows a BarComboBox used as a color picker.  That's a good example to study if you want to use BarComboBox.  You're probably just missing the "TextMemberBinding" to get the selection box to show the text.  Then the "InlineIconMemberBinding" can be used to display an inline icon, in this case, the selected color.

Hi,

Thanks do much for the quick and comprehensive answer. I guess I was just curious if I was missing something obvious but the idea that the BarCombo isn't really designed for this makes sense. I did get it working in our old WPF app with a ComboBox and kind of got it going with binding the main control background with your control but your suggestion to use a popup and a gallery item is a much better one.

I now have a much nicer colour picker and a single icon button that reflects the icon/colour chosen, and conforming to the way that these controls are supposed to be used.

Once more question while I am here: I am using the MVVM approach for the menu bar, so creating either a built-in or custom (derived) vm for each ribbon menu component. For some of these components - e.g. this colour gallery - I want to use basically the identical component in a separate dialog as well. Is there an MVVM way to do this or does the axaml need to wire up all the bindings to the custom BarPopupButtonViewModel that I have created? I have a tried a few things, including creating just a content control with a binding to the vm, but although this does create the right control it doesn't populate menu items etc.

thanks!

Matt

Hi Matt,

For an MVVM implementation, you would need an IItemContainerTemplateSelector in place to watch for your custom viewmodel type and return a template that initializes the color gallery with all its properties set directly or via bindings.  Our MVVM Support documentation topic covers the concepts of how MVVM works.  The container template selector is important because if implemented correctly, it will recurse down the control hierarchy and be able to fill out menu items, etc.

That being said, you really need a root control that knows how to use the IItemContainerTemplateSelector.  Ribbon, BarMainMenu, StandaloneToolBar, etc. are examples of those kinds of root controls.  The IItemContainerTemplateSelector is used to make "containers" for the children of them, but it can't style the root control itself.

If you have your color gallery just completely standalone somewhere, then you'd have to configure its properties and bindings in XAML.  You could set its BarControlService.ItemContainerTemplateSelector attached property to your IItemContainerTemplateSelector instance and that should allow the menu items to be created using the container template selector.

I hope that points you in the right direction.  If not, feel free to follow up with some more details and we can assist further.