I have an Area object which has many SubArea children:
public class Area
{
...
public virtual IList<SubArea> SubAreas { get; set; }
}
he children are mapped as a uni-directional non-inverse relationship:
public class AreaMapping : ClassMap<Area>
{
public AreaMapping()
{
HasMany(x => x. SubAreas).Not.Inverse().Cascade.AllDeleteOrphan();
}
}
The Area is my aggregate root. When I save an area (e.g. Session.Save(area) ), the area gets saved and the child SubAreas automatically cascaded.
I want to add a save or update event listener to catch whenever my areas and/or subareas are persisted. Say for example I have an area, which has 5 SubAreas. If I hook into SaveEventListeners:
Configuration.EventListeners.SaveEventListeners =
new ISaveOrUpdateEventListener[] { mylistener };
When I save the area, Mylistener is only fired once only for area (SubAreas are ignored). I want the 5 SubAreas to be caught aswell in the event listener. If I hook into SaveOrUpdateEventListeners instead:
Configuration.EventListeners.SaveOrUpdateEventListeners =
new ISaveOrUpdateEventListener[] { mylistener };
When I save the area, Mylistener is not fired at all. Strangely, if I hook into SaveEventListeners and SaveOrUpdateEventListeners:
Configuration.EventListeners.SaveEventListeners =
new ISaveOrUpdateEventListener[] { mylistener };
Configuration.EventListeners.SaveOrUpdateEventListeners =
new ISaveOrUpdateEventListener[] { mylistener };
When I save the area, Mylistener is fired 11 times: once for the area, and twice for each SubArea! (I think because NHIbernate is INSERTing the SubArea and then UPDATING with the area foreign key).
Does anyone know what I'm doing wrong here, and how I can get the listener to fire once for each area and subarea?
Not 100% related to your question but if you map with inverse="true" on your collection you atleast dont get the insert AND update statements.
NH issues INSERT statement in order to know the Id of the object if it cannot known (IDENTITY or SEQUENCE for example).
So if you want to void that you need to use an id generator that do not require roundtript to the DB (such as guid or guid.combo).
Related
I want to present a list of up to 20 panels within a <MudExpansionPanels> component where the expanded child portion of each <MudExpansionPanel> is expensive to render. I tried the following test code but all instances of <LiveAgentSummary> are rendered as the parent is rendered, just to clarify this rendering of <LiveAgentSummary> happens before any panel is manually expanded.
<MudExpansionPanels>
#foreach (var liveAgent in _liveAgents)
{
<MudExpansionPanel Text=#liveAgent.Name>
<LiveAgentSummary AgentId=#liveAgent.Id />
</MudExpansionPanel>
}
</MudExpansionPanels>
I then looked into delaying the render of each <LiveAgentSummary> through use of a RenderFragment that is dynamically built during the <MudExpansionPanel> IsExpandedChanged event. However the event handler does not indicate which panel is being expanded and hence I do not know which liveAgent.Id param value to pass to <LiveAgentSummary> as I build a RenderFragment.
I think <MudExpansionPanels> is missing support for a bind-ActivePanelId property but hopefully I am overlooking an alternative solution to my delayed rendering objective.
This is the official MudBlazor example that prompted me to look into using a RenderFragment.
Update: A long answer briefly appeared yesterday suggesting that I could query the list of panel components on a built-in property that indicates the expanded state. The poster had gone to the trouble of reading the MudBlazor source code but the answer was then deleted.
I am now wondering how from code in an event handler it is possible to iterate over a component hierarchy declared as mark-up. Applying this to my example markup above, how could event handler code obtain a reference to each <MudExpansionPanel> child within <MudExpansionPanels>.
Can't you make use of the bool from the IsExpandedChanged callback? Something like this:
Index.razor
#page "/"
<MudExpansionPanels>
#foreach (var liveAgent in this.liveAgents)
{
<MudExpansionPanel
Text="#($"{liveAgent.Name} ({liveAgent.Data})")"
IsExpandedChanged="#(e => this.Load(e, liveAgent))">
<LiveAgentSummary Agent="#liveAgent" />
</MudExpansionPanel>
}
</MudExpansionPanels>
#code {
private readonly List<Agent> liveAgents = new()
{
new Agent("1", "Agent Smith"),
new Agent("2", "Agent Brown"),
new Agent("3", "Agent Jones")
};
private void Load(bool expanded, Agent agent)
{
if (expanded)
{
agent.Load();
}
}
}
LiveAgentSummary.razor
<MudText>id: #this.Agent.Id, data: #this.Agent.Data</MudText>
#code {
[Parameter]
public Agent Agent { get; set; } = default!;
}
Agent.cs
public record Agent(string Id, string Name)
{
public string Data { get; set; } = "Not loaded";
public void Load()
{
Console.WriteLine($"Loading agent {this.Id}...");
this.Data = "Loaded!";
}
}
I'm using two tables, the first one contains "Teams", the second one "Team members" and is populating based on the first table selection. I'm also showing various stats depending on the selection, be it a team or a specific member. If no member is selected, team stats are showed, otherwise member stats are showed.
I'm using ItemChangeListeners on the tables to redraw the stats, but this prevents me to click on an already selected team to "deselect" a selected member from that team, since no event is triggered in that circumstance. As a solution I'm also using a ClickListener on the Team table, but it seems to work only if I click on the word (instead of working on the whole cell).
teamsTable.setClickListener("name", new Table.CellClickListener() {
#Override
public void onClick(Entity item, String columnId) {
if (teamsDs.getItem() == item) {
teamsDs.setItem(null);
teamsDs.setItem((Team) item);
} else {
teamsDs.setItem((Team) item);
teamsTable.setSelected((Team) item);
}
}
});
Is there a better way to catch a click on a table cell? Or is there a better way to approach the problem altogether?
Since CUBA Table is a wrapper of Vaadin table you can use ItemClickListener from Vaadin with CUBA table:
public class DemoScreen extends AbstractWindow {
#Inject
private Table<User> usersTable;
#Override
public void init(Map<String, Object> params) {
super.init(params);
com.vaadin.ui.Table vTable = usersTable.unwrap(com.vaadin.ui.Table.class);
vTable.addItemClickListener((ItemClickEvent.ItemClickListener) event ->
showNotification("Item " + event.getItemId())
);
}
}
It will be fired each time you click on a table cell.
In my current project I would like to be able to create new objects when searching for a reference object. This happens in several places of the application.
For example, let's assume we have a City Entity and a Country Entity. The City entity has a mandatory reference to the Country entity.
In my use case, I would like to create a new City. When I do this, I will have to assign a Country to the new City. When I click on the lookup icon, I get the selection dialog with all existent countries. But if I don't have the Country I want, I have to abort the operation, get back to the countries list and create the new one I'd like to assign to my new city.
Would it be possible to create that new Country from the selection dialog with all countries?
If it is possible, is the country being added to the list right after it has been created?
Would it be possible to one define a range for the countries list? For example, showing only countries in Europe, if the user is in Europe.
I could imagine, that this would be a lot to ask from the framework. But I am just giving a shot and perhaps also giving a new feature idea, which would be nice to have.
Customization of the LOV dialog :
You can easily customize the LOV dialog by creating your own class of the LOV action that is installed next to the reference fields.
Adding a new action in the dialog (the create action) :
public class LovActionWithCreate<E, F, G> extends LovAction<E, F, G> {
private IDisplayableAction createAction;
#Override
protected void feedContextWithDialog(IReferencePropertyDescriptor<IComponent> erqDescriptor,
IQueryComponent queryComponent, IView<E> lovView, IActionHandler actionHandler,
Map<String, Object> context) {
super.feedContextWithDialog(erqDescriptor, queryComponent, lovView, actionHandler, context);
List<IDisplayableAction> defaultLovDialogActions = (List<IDisplayableAction>) context.get(
ModalDialogAction.DIALOG_ACTIONS);
defaultLovDialogActions.add(1, getCreateAction());
}
/**
* Gets create action.
*
* #return the create action
*/
protected IDisplayableAction getCreateAction() {
return createAction;
}
/**
* Sets create action.
*
* #param createAction
* the create action
*/
public void setCreateAction(IDisplayableAction createAction) {
this.createAction = createAction;
}
}
The key point is to override the feedContextWithDialog method in order to install the new action into the dialog.
Next step is to install your new LOV action. You can either do it globally for whole application or per reference view :
replacing the LOV action globally is just a matter of declaring an action named 'lovAction' into your application frontend.groovy, i.e. :
action('lovAction', parent: 'lovActionBase', class:'test.LovActionWithCreate',
custom: [createAction_ref:'theCreateAction']
)
replacing the LOV action on a certain reference field in a form can be done by using the referencePropertyView (in a form or in a table) and its 'lovAction' property, e.g. :
action('lovActionWithCreate', parent: 'lovActionBase', class:'test.LovActionWithCreate',
custom: [createAction_ref:'theCreateAction']
)
form('ACertainForm'){
fields {
...
referencePropertyView name:'country', lovAction:'lovActionWithCreate'
...
}
}
Creating an entity in the LOV dialog :
In the next step, we create the action that will be responsible for opening an extra dialog in order to create the new entity, persist it and, if successful, add it to the LOV result view. This is a little more complicated but not that much.
First of all, we have to open a new dialog.
For doing this, we will inherit the built-in EditComponentAction. The goal of this action is to edit a model in a modal dialog. The only difficulty here is that our model is only known at runtime. No problem though as we will use the dynamic nature of Jspresso.
public class CreateEntityFromLOVAction<E, F, G> extends EditComponentAction<E,F,G> {
#Override
protected Object getComponentToEdit(Map<String, Object> context) {
IEntityFactory entityFactory = getBackendController(context).getEntityFactory();
IQueryComponent lovQueryComponent = (IQueryComponent) context.get(IQueryComponent.QUERY_COMPONENT);
Class<IEntity> entityToCreateContract = lovQueryComponent.getQueryContract();
IEntity entityInstance = entityFactory.createEntityInstance(entityToCreateContract);
setActionParameter(Arrays.asList(entityInstance), context);
return entityInstance;
}
#Override
protected IViewDescriptor getViewDescriptor(Map<String, Object> context) {
IEntityFactory entityFactory = getBackendController(context).getEntityFactory();
IQueryComponent lovQueryComponent = (IQueryComponent) context.get(IQueryComponent.QUERY_COMPONENT);
Class<IEntity> entityToCreateContract = lovQueryComponent.getQueryContract();
IComponentDescriptor<?> entityToCreateDescriptor = entityFactory.getComponentDescriptor(entityToCreateContract);
BasicComponentViewDescriptor formViewDescriptor = new BasicComponentViewDescriptor();
formViewDescriptor.setModelDescriptor(entityToCreateDescriptor);
return formViewDescriptor;
}
}
If you look at the code above, our new action takes care of the following :
Get the type of entity to create from the context. For this, we are just exploring the query component which is the model of the LOV dialog.
Create the entity instance and set it as action parameter in the context for the chain to continue working on it (save, close dialog).
Create a form to display in the creation dialog.
Points 1 and 2 are handled by the getComponentToEdit method and point 3 by the getViewDescriptor method.
Next, when the user clicks Ok, we have to save the entity, add it to the LOV result list and close the creation dialog.
For this, we will create a new action and chain it to the saveAction and closeDialogAction built-in actions.
public class CreateEntityFromLOVPersistAction<E, F, G> extends FrontendAction<E,F,G> {
#Override
public boolean execute(IActionHandler actionHandler, Map<String, Object> context) {
if (super.execute(actionHandler, context)) {
IQueryComponent lovQueryComponent = (IQueryComponent) context.get(IQueryComponent.QUERY_COMPONENT);
List<IEntity> createdEntityInstance = getActionParameter(context);
lovQueryComponent.setQueriedComponents(createdEntityInstance);
return true;
}
return false;
}
}
And the final wiring in SJS frontend.groovy:
action('createEntityFromLovOkAction', parent: 'okDialogFrontAction',
class:'test.CreateEntityFromLOVPersistAction',
wrapped: 'saveBackAction', next: 'closeDialogAction')
action('createEntityFromLovAction', parent: 'editComponentAction',
class: 'test.CreateEntityFromLOVAction',
name:'add.name', custom: [
okAction_ref: 'createEntityFromLovOkAction'
]
)
action('lovAction', parent: 'lovActionBase',
class:'test.LovActionWithCreate',
custom: [createAction_ref:'createEntityFromLovAction']
)
A long answer for less than 100 lines of code, but now you have a fully generic LOV action where the user can create any missing master data without leaving his current screen.
Presetting some data in the LOV filter depending on the user context :
For this, we generally use the initialization mapping that allows for setting some restrictions (either static or dynamic) on a reference property when it is queried in a LOV. For instance, let's consider the following use case :
You have 2 entities, Contract and Tariff, that are linked together through a 1-N relationship, i.e. a Contract is linked to 1 Tariff.
Contract and Tariff both have a country property and a Tariff can be assigned to a Contract if and only if they belong to the same country.
Tarrif has a status property and can only be used in a Contract if its status is ACTIVE.
You can simply enforce these rules in the LOV by setting the initialization mapping on the reference property the following way :
Entity('Contract', ...) {
...
reference 'tariff', ref: 'Tariff',
initializationMapping: [
'country': 'country',
'status': 'ACTIVE'
]
...
}
Thinking about it, this kind of behavior might very well find its way to the framework, so please, feel free to ope an enhancement request in the Jspresso GitHub.
I've got a Silverlight 4 RIA Services (SP1) app using Entity Frameworks 4 CTP5. I can databind a grid or listbox to the IEnumerable loaded by the domain context and it shows data from the server. Great.
Now I want to create a new instance of MyEntity and add it to the client-side data so that the user can see the newly added entity. MyEntity is a true entity descendant, not a POCO.
The only Add method I can find is domainContext.EntityContainer.GetEntitySet<MyEntity>().Add(newobj)
This does add the new entity to the domain context, and the domainContext.HasChanges does become true, but the new entity doesn't show up in the databound controls.
How do I get the new entity to show up in the databound controls prior to SubmitChanges?
(Probably related to this SO question from years ago that never got an answer)
Here's the server side declarations of the domain service, per requests:
[EnableClientAccess()]
public class MyDomainService : LinqToEntitiesDomainService<MyObjectContext>
{
protected override MyObjectContext CreateObjectContext()
{
return new MyObjectContext();
}
public IQueryable<MyEntity> GetMyEntities()
{
return this.ObjectContext.MyEntities;
}
public void InsertMyEntity(MyEntity MyEntity)
{
// ...
}
public void UpdateMyEntity(MyEntity currentMyEntity)
{
// ...
}
public void DeleteMyEntity(MyEntity MyEntity)
{
// ...
}
}
I've figured this out with a combination of my own trial and error and hints provided by some of the other responses to this question.
The key point I was missing was that it's not enough for the ViewModel to keep track of the DomainContext and hand out query results to the View for databinding. The ViewModel also has to capture and retain the query results if you want entity adds and deletes performed by the ViewModel to appear in the UI before DomainContext.SubmitChanges(). The ViewModel has to apply those adds to the collection view of the query results.
The ViewModel collection property for View databinding. In this case I'm using the Telerik QueryableDomainServiceCollectionView, but other collection views can be used:
public IEnumerable<MyEntity> MyEntities
{
get
{
if (this.view == null)
{
DomainContextNeeded();
}
return this.view;
}
}
private void DomainContextNeeded()
{
this.context = new MyDomainContext();
var q = context.GetMyEntitiesQuery();
this.view = new Telerik.Windows.Data.QueryableDomainServiceCollectionView<MyEntity>(context, q);
this.view.Load();
}
The ViewModel function that adds a new entity for the UI to display:
public void AddNewMyEntity(object selectedNode)
{
var ent = new MyEntity() { DisplayName = "New Entity" };
if (selectedNode == null)
{
this.view.AddNew(ent);
}
else if (selectedNode is MyEntity)
{
((MyEntity)selectedNode).Children.Add(ent);
}
}
Other responses mentioned ObservableCollection. The query results and the collection view may not return instances of ObservableCollection. They could be just IEnumerables. What is critical is that they implement INotifyCollectionChanged and IEditableCollectionView.
Thanks to those who contributed responses. I've +1'd each response that was helpful, but since none directly solved my problem I couldn't justify marking any as the definitive answer.
Your domainContext will have a property domainContext.MyEntities. Does it not show up in there when you add it?
Bind to that collection or watch that collection for changes.
domainContext.MyEntities.PropertyChanged += MyEventHandler;
I assume you bind your control to the IEnumerable which is provided by LoadOperation<TEntity>.Entities. In that case your binding source is not the DomainContext.GetEntitySet<MyEntity>().
DomainContext.GetEntitySet<MyEntity>() holds all your currently tracked instances of MyEntity, including the one you add with .Add().
LoadOperation<TEntity>.Entities only contains the instances of MyEntity that were actually loaded by your last LoadOperation/Query.
You have two options: Either add the new entity to the ItemsSource-collection for your control (I recommend that) or rebuild the collection with the contents of DomainContext.GetEntitySet<MyEntity>(). That may contain other elements that you have not cleared out before, though.
The entities and mappings I'm talking about in this question can be found here :)
Here is the context:
I have a parent view-model which helps to manage some entities, and which has its own session.
From this VM, I open another view-model (with its own session too), do some changements to the entity (add and/or remove children), and when I validate the changements, I commit the session and warns the first view-model to refresh the display:
public void Validate()
{
using (var tx = Session.BeginTransaction())
{
try
{
SelectedTeam.ClearRoster();
foreach (var teamPlayer in TeamPlayers)
SelectedTeam.AddPlayer(teamPlayer);
teamsRepository.SaveOrUpdate(SelectedTeam);
tx.Commit();
}
catch (Exception ex)
{
tx.Rollback();
}
finally
{
if (tx.WasCommitted)
ServiceLocator.Current.GetInstance<Mediator>().NotifyColleagues(MediatorMessages.DisplayEntityInfos, SelectedTeam.Id);
}
}
}
Here is the faulted method of the parent VM:
public void RefreshEntitiesListAndDisplayEntityInfos(int selectedEntityId)
{
TEntity entity = entitiesRepository.Load(selectedEntityId);
Session.Refresh(entity);
//...
}
The exception is thrown at the Refresh line:
NHibernate.UnresolvableObjectException
And the message is:
No row with the given identifier exists[Emidee.CommonEntities.PlayerInTeam#3
I can open and change the entity multiple times, but it seems that the exception is thrown when I delete a children, then add another one, and finally delete another one.
After some readings on the web, it seems that's because when I refresh the entity, and because I changed the HasMany relationship (because I have deleted a player for example), NH tries to reload the deleted row.
I've tried to add a NotFound.Ignore statement on the HasMany in my mappings, I've tried to force a new query to the DB instead of a Load, but I still get this exception.
Does someone know how I could fix that?
Thanks in advance
Mike
This is a known behavior when refreshing objects with modified collections.
To force reload, change your method to do session.Evict with the entity as a parameter. This is the code we use in our base model class:
public T ReGet<T>(T entity) where T : IEntity
{
var id = entity.Id;
Session.Evict(entity);
return Session.Get<T>(id);
}
Well, I've just spotted the problem.
To update the players list of the team, I used to clear the list, and add the new players, before updating the entity.
Now, I update the list by removing and adding only the players who have been moved by the user, and I don't have any problems at all now.
That's weird. I don't know what was wrong before, but as least that works now.