/// <summary>
/// The logic used whenever a dependent locator is swapped.
/// </summary>
/// <param name="newLocator">The new locator.</param>
/// <param name="oldLocator">The old locator.</param>
/// <param name="token">The token to use to lock.</param>
protected void ProcessLocatorSwap(ILocator newLocator, ILocator oldLocator, object token)
{
if (oldLocator != null)
{
Locators.Remove(oldLocator);
oldLocator.SearchToBegin -= Locator_SearchToBegin;
oldLocator.SearchComplete -= Locator_SearchComplete;
oldLocator.RecordRequested -= Locator_RecordRequested;
}
if (newLocator != null)
{
Locators.Add(newLocator);
newLocator.RequestClear();
newLocator.RequestDisable(token);
newLocator.SearchToBegin += Locator_SearchToBegin;
newLocator.SearchComplete += Locator_SearchComplete;
newLocator.RecordRequested += Locator_RecordRequested;
}
}
/// <summary>
/// The logic used to update the <see cref="ModelSearcher" />.
/// </summary>
/// <param name="searcher">The new <see cref="ModelSearcher" />.</param>
/// <returns>Task for async use.</returns>
public async Task UpdateModelSearcher(IVMLocator <TModelSearcher> searcher)
{
var oldValue = _modelSearcher;
if (Perform.ReplaceIfDifferent(ref _modelSearcher, searcher).WasSuccessful)
{
if (oldValue != null)
{
Locators.Remove(oldValue);
oldValue.SelectedItems.CollectionChanged -= SelectedItems_CollectionChanged;
oldValue.ExportId -= ModelSearcher_ExportId;
oldValue.Cleared -= ModelSearcher_Cleared;
}
if (_modelSearcher != null)
{
_modelSearcher.SelectedItems.CollectionChanged += SelectedItems_CollectionChanged;
_modelSearcher.ExportId += ModelSearcher_ExportId;
_modelSearcher.Cleared += ModelSearcher_Cleared;
Locators.Add(_modelSearcher);
if (_modelSearcher.CurrentItems.Any())
{
var navCollection =
(_modelSearcher.SelectedItems.Take(2).Count() == 2 ?
_modelSearcher.SelectedItems :
_modelSearcher.CurrentItems
);
_backForwardNavigator.UpdateNavigationCollection(navCollection.Select(item => item.Id));
int currentItem =
(_modelSearcher.SelectedItems.Any() ?
_modelSearcher.SelectedItems :
_modelSearcher.CurrentItems
).First().Id;
await _backForwardNavigator.UpdateCurrentItem(currentItem);
}
}
await OnModelSearcherSwapped(oldValue);
OnPropertyChanged(nameof(ModelSearcher));
}
}
