private void PresentViewModels()
{
// If there's no data then there's nothing to do.
if (_instancesPerZone == null)
{
return;
}
IEnumerable<TreeNode> viewModels;
if (_showZones)
{
// This query creates the zone view model with the following steps:
// * Create an object that represents the zone and the instances that must be shown (after filtering)
// for that zone. The instances in the zone are sorted by their name.
// * Filter out the zones that (after filtering instances) are empty.
// * Sort the resulting zones by the zone name.
// * Create the view model for each zone, containing the instances for that zone.
viewModels = _instancesPerZone
.Select(x => new
{
Zone = x.Zone,
Instances = x.Instances
.Where(i => _showOnlyWindowsInstances ? i.IsWindowsInstance() : true)
.OrderBy(i => i.Name)
})
.Where(x => x.Instances.Count() > 0)
.OrderBy(x => x.Zone.Name)
.Select(x => new ZoneViewModel(this, x.Zone, x.Instances.Select(i => new GceInstanceViewModel(this, i))));
}
else
{
// This query gets the list of view models for the instnaces with the following steps:
// * Select all of the instances in all of the zones in a source list.
// * Filters the instances according to the _showOnlyWindowsInstances setting.
// * Sorts the resulting instances by name.
// * Creates the view model for each instance.
viewModels = _instancesPerZone
.SelectMany(x => x.Instances)
.Where(x => _showOnlyWindowsInstances ? x.IsWindowsInstance() : true)
.OrderBy(x => x.Name)
.Select(x => new GceInstanceViewModel(this, x));
}
UpdateViewModels(viewModels);
}
