Closes: #40382
## To-do list
- [x] Add support for "single-select" filters to DynamicListPage
- [x] Filters can contain icons
- [x] Filter list can contain separators
- [x] Update Windows Services built-in extension to support filtering by
all, started, stopped, and pending services
- [x] Update SampleExtension dynamic list sample to filter.
## Example of filters in use
```C#
internal sealed partial class ServicesListPage : DynamicListPage
{
public ServicesListPage()
{
Icon = Icons.ServicesIcon;
Name = "Windows Services";
var filters = new ServiceFilters();
filters.PropChanged += Filters_PropChanged;
Filters = filters;
}
private void Filters_PropChanged(object sender, IPropChangedEventArgs args) => RaiseItemsChanged();
public override void UpdateSearchText(string oldSearch, string newSearch) => RaiseItemsChanged();
public override IListItem[] GetItems()
{
// ServiceHelper.Search knows how to filter based on the CurrentFilterIds provided
var items = ServiceHelper.Search(SearchText, Filters.CurrentFilterIds).ToArray();
return items;
}
}
public partial class ServiceFilters : Filters
{
public ServiceFilters()
{
// This would be a default selection. Not providing this will cause the filter
// control to display the "Filter" placeholder text.
CurrentFilterIds = ["all"];
}
public override IFilterItem[] GetFilters()
{
return [
new Filter() { Id = "all", Name = "All Services" },
new Separator(),
new Filter() { Id = "running", Name = "Running", Icon = Icons.GreenCircleIcon },
new Filter() { Id = "stopped", Name = "Stopped", Icon = Icons.RedCircleIcon },
new Filter() { Id = "paused", Name = "Paused", Icon = Icons.PauseIcon },
];
}
}
```
## Current example of behavior
https://github.com/user-attachments/assets/2e325763-ad3a-4445-bbe2-a840df08d0b3
---------
Co-authored-by: Mike Griese <migrie@microsoft.com>
What the title says. 😄
Rather than relying on the potentially overloaded `!=` or `==` operators
when checking for null, now we'll use the `is` expression (possibly
combined with the `not` operator) to ensure correct checking. Probably
overkill for many of these classes, but decided to err on the side of
consistency. Would matter more on classes that may be inherited or
extended.
Using `is` and `is not` will provide us a guarantee that no
user-overloaded equality operators (`==`/`!=`) is invoked when a
`expression is null` is evaluated.
In code form, changed all instances of:
```c#
something != null
something == null
```
to:
```c#
something is not null
something is null
```
The one exception was checking null on a `KeyChord`. `KeyChord` is a
struct which is never null so VS will raise an error when trying this
versus just providing a warning when using `keyChord != null`. In
reality, we shouldn't do this check because it can't ever be null. In
the case of a `KeyChord` it **would** be a `KeyChord` equivalent to:
```c#
KeyChord keyChord = new ()
{
Modifiers = 0,
Vkey = 0,
ScanCode = 0
};
```
I just blindly moved all the messages. But _this_ one really makes more
sense as a UI message. It's got framework elements. It us used to
actually open a UI element. The whole thing is very UI specific.
re: #40113
_targets #40504_
Major refactoring for #40113
This moves a large swath of the codebase to a `.Core` project. "Core"
doesn't have any explicit dependencies on "extensions", settings or the
current `MainListPage`. It's just a filterable list of stuff. This
should let us make this component a bit more reusable.
This is half of a PR. As I did this, I noticed a particular bit of code
for TopLevelVViewModels and CommandPaletteHost that was _very rough_.
Solving it in this PR would make "move everything to a new project" much
harder to review. So I'm submitting two PRs simultaneously, so we can
see the changes separately, then merge together.
Refactored ContextMenu into it's own control to allow displaying in
CommandBar and in response to right click on list items.
- Adds "critical" styling to context menu items flagged as `IsCritical`.
This will use the theme to style with correct color.
- Added `SeparatorContextItem` and modified `MoreCommands` to allow for
both `CommandContextItem`s and `SeparatorContextItem`s.
- Right clicking a list item with a context menu will open the context
menu at the position of the click and position the filter box at the top
of the context menu.


This PR covers:
- closes#38308
- closes#39211
- closes#38307
- closes#38261