/// <summary>
/// Initializes a new instance of the AdvancedSearchViewModel class
/// </summary>
public AdvancedSearchViewModel()
{
scope = Data.GraphManager.Instance.DefaultGraphComponentsInstance.Scope;
// Setup a listener for the AttributeListUpdated event
Data.Attributes.GlobalAttributeCollection.GetInstance(this.scope).AttributeListUpdated += new EventHandler <Data.Attributes.AttributeEventArgs>(GlobalAttributeCollection_AttributeListUpdated);
// Get a list of all the attributes
Attributes = new ObservableCollection <string>(Data.Attributes.GlobalAttributeCollection.GetInstance(scope).GetAttributes().Where(attribute => attribute.Visible).Select(attribute => attribute.Name));
// Get a list of all valid operators
Operators = new ObservableCollection <string>(ExtensionMethods.GetNames(typeof(SearchOperator)));
// Make sure that we have one criterion and that it is disabled
// and inactive.
SearchCriterionViewModel newSearchCriterion = new SearchCriterionViewModel(this)
{
IsEnabled = true, IsActive = false
};
SearchCriteria.Add(newSearchCriterion);
// Wire up event handlers for the Activated and Deactivated events of
// the newly created SearchCriterion control
newSearchCriterion.Activated += new EventHandler <EventArgs>(SearchCriterion_Activated);
newSearchCriterion.Deactivated += new EventHandler <EventArgs>(SearchCriterion_Deactivated);
}
/// <summary>
/// Handles the Deactivated event for any SearchCriterion control. This event
/// is fired when a SearchControl is made inactive, which means it should be
/// removed.
/// </summary>
/// <param name="sender">The specific SearchCriterion instance that fired the event</param>
/// <param name="e">Event arguments for the event</param>
private void SearchCriterion_Deactivated(object sender, EventArgs e)
{
SearchCriterionViewModel criterion = sender as SearchCriterionViewModel;
// Check if we have more than one SearchCriterion controls
if (SearchCriteria.Count > 1)
{
// Remove the SearchCriterion from the collection
SearchCriteria.Remove(criterion);
// Remove event handlers
criterion.Activated -= new EventHandler <EventArgs>(SearchCriterion_Activated);
criterion.Deactivated -= new EventHandler <EventArgs>(SearchCriterion_Deactivated);
}
else
{
// Set the IsActive property to false which will trigger the
// underlying StoryBoard to disable the input controls.
criterion.IsActive = false;
}
}
/// <summary>
/// Handles the Activated event for any SearchCriterion control. This event
/// is fired when a SearchCriterion is made active, which mean that the input
/// controls should be activated and a new (inactive) control should be created.
/// However, if a control is not valid, a new control can't be added.
/// </summary>
/// <param name="sender">The specific SearchCriterion instance that fired the event</param>
/// <param name="e">Event arguments for the event</param>
private void SearchCriterion_Activated(object sender, EventArgs e)
{
bool addNew = true;
SearchCriterionViewModel sourceCriterion = sender as SearchCriterionViewModel;
// Check how many SearchCriterion controls we currently have
if (SearchCriteria.Count > 1)
{
// Loop through all SearchCriterion view models in our list
foreach (SearchCriterionViewModel criterion in SearchCriteria)
{
// If this criterion control is the one that fired the Activate
// event, just skip it
if (criterion == sourceCriterion)
{
continue;
}
// Check if the SearchCriterion is currently active
if (criterion.IsActive)
{
// Validate the Search Criterion
criterion.Validate();
if (!criterion.IsValid)
{
// Set a flag that we don't actually want to create
// a new Criterion because this one was invalid.
addNew = false;
SelectedCriterion = criterion;
}
}
}
}
// Check if we are actually adding a new SearchCritrion control
if (addNew)
{
// Set the IsActive property to true which will trigger the
// underlying StoryBoard to enable the input controls.
sourceCriterion.IsActive = true;
// Make sure that we have one criterion and that it is disabled
// and inactive.
SearchCriterionViewModel newSearchCriterion = new SearchCriterionViewModel(this)
{
IsEnabled = true, IsActive = false
};
SearchCriteria.Add(newSearchCriterion);
SelectedCriterion = sourceCriterion;
// Wire up event handlers for the Activated and Deactivated events of
// the newly created SearchCriterion control
newSearchCriterion.Activated += new EventHandler <EventArgs>(SearchCriterion_Activated);
newSearchCriterion.Deactivated += new EventHandler <EventArgs>(SearchCriterion_Deactivated);
}
else
{
sourceCriterion.IsActive = false;
}
}