Ok so I am really stuck now. I have a h:datatable and the only way to get the row details seems to be DataModel#getRowData(). Unfortunately ListDataModel which is needed to wrap the necessary data is NOT serializable so will not work on GAE, and I really need it to work! Does anyone have any idea about any workaround or some way to make it function.
Help much appreciated!
Mark the property transient (so that it will be skipped during serialization) and introduce lazy loading in the getter.
E.g.
private List<Item> itemList;
private transient DataModel<Item> itemModel;
public DataModel<Item> getItemModel() {
if (itemModel == null) {
itemModel = new ListDataModel<Item>(itemList);
}
return itemModel;
}
There are by the way alternate ways to retrieve the current row. See also How can I pass selected row to commandLink inside dataTable?
Related
Specifically this is a follow-up to this question DataGrid filter performance, but there are many more similar questions relating to WPF DataGrid performance on StackOverflow.
After a lot of profiling and going through .NET source code, I have realized that many performance issues, such as filtering and sorting, boil down just one issue: A CollectionView.Reset event does not recycle containers (like scrolling does).
What I mean is that instead of assigning the existing rows a new datacontext, all rows are removed from the visual tree, new rows are generated and added, and a layout cycle (measure and arrange) is performanced.
So the main question is: Has anyone successfully managed to work around this? E.g. by manually manipulating the ItemContainerGenerator, or by creating their own version of the DataGridRowsPresenter?
So this is the gist of my approach so far.
public class CollectionViewEx
{
public event EventHandler Refresh;
public override void Refresh()
{
Refresh?.Invoke(this, EventArgs.Empty);
}
}
public class DataGridEx : DataGrid
{
protected override OnItemsSourceChanged(IEnumerable oldSource, IEnumerable newSource)
{
if (newSource is CollectionViewEx cvx)
{
cvx.Refresh += (o,a) => OnViewRefreshing;
}
}
private void OnViewRefreshing()
{
RowsPresenter.Refresh();
}
}
public class DataGridRowsPresenterEx : DataGridRowsPresenter
{
public void Refresh()
{
var generator = (IRecyclingItemContainerGenerator)ItemContainerGenerator;
generator.Recycle(new GeneratorPosition(0, 0), ???);
RemoveInternalChildRange(0, VisualChildrenCount);
using (generator.StartAt(new GeneratorPosition(-1, 0), GeneratorDirection.Forward))
{
UIElement child;
bool isNewlyRealised = false;
while ((child = generator.GenerateNext(out isNewlyRealised) as UIElement) != null)
{
AddInternalChild(child);
generator.PrepareItemContainer(child);
}
}
}
}
But the results are very confusing - obviously because I don't quite understand how to work with the ICG.
I have looked through .net source code to see their implementations (when adding/removing/replacing items), and also found a couple of online resources on how to create a new virtualized panel (e.g. virtualizingwrappanel), but none really address this particular issue, where we want to reuse all existing containers for a new set of items.
So the secondary question is: Can anyone explain if this approach is even possible? How would I do it?
I never use reset directly from CollectionView because a methode on CollectionView's Source do it. This IList is modified for my needs. I did it like Paul McClean explained here.
In this class you could notify OnCollectionChanged to inform the CollectionView. sondergard explained what NotifyCollectionChangedAction.Reset do. But NotifyCollectionChangedAction.Replace keep running the recyling for the Items.
Maybe my research helps.
TL;DR: How do I combine info from two database tables into a Vaadin Treetable (or, when Vaadin 7.5 is released, a heirarchical Grid)?
I have a Java Swing desktop application that does this currently, albeit probably very ineffeciently with ArrayLists of Java Beans that updates from the SQL Server every 30 seconds. Well, I'm now attempting to port this desktop app over to a Vaadin web app. The desktop app has login capabilities and I'll eventually worry about doing the same for the web app, but for now, I just want to try and get the most basic part of this web app working: The Treetable. Or, hopefully soon, a heirarchical Grid.
To help illustrate what I'm aiming for, I'll try and post an image I created that should show how the data from the two tables needs to merge into the treetable (using a partial screenshot of my existing desktop app):
I am well aware of how to use the JOIN command in SQL and I've briefly read about Referencing Another SQLContainer, but I'm still in the early stages of learning Vaadin and still trying to wrap my head around SQLContainer, FreeformQuery, and how I need to implement FreeformStatementDelegate for my project. Not to mention that I'll need to implement checkboxes for each row, as you can see in that photo, so that it updates the database when they are clicked. And a semi-checked state for the checkbox would be necessary for Jobs that have more than one OrderDetail item wherein only some of those OrderDetail items are completed. To get that working for my Java Swing program, I had to lean on an expert Java developer who already had most of the code ready, and boy, is it super-complicated!
If anyone can give me a high-level view of how to accomplish this task along with some examples, I would be indebted. I totally understand that I'm asking for a great deal here, and I'm willing to take it slow, step-by-step, as long as you are. I really want to fully understand this so I'm not just copy-pasting code without thinking.
I have never used SQLContainer so this might not be the answer you want. I just had a quick look at SQLContainer and I'm not sure if it will serve your purpose. For a TreeTable you will need a Container Implementing the Container.Hierarchical interface or the table will put a wrapper around it and you have to set the parent-children relations manually. You probably could extend SQLContainer and implement the methods from Container.Hierarchical in that class but this might get complicated.
In your situation I think I'd go with implementing my own Container, probably extending AbstractContainer, to get the listener code for free, and implementing Hierarchical. There are quite some methods to implement, I know, and so this will need some time, but most methods are quickly implemented and you can start with the basic methods and add more interfaces (Ordered, Sortable, Indexed, Filterable, Collapsible,...) later.
If done properly you'll end up with with easy readable code that can be extended in the future without to much trouble and you will not depend on future versions of SQLContainer.
Another good thing is that you'll learn a lot about the data structures (Container, Item, Property) used in vaadin. But as I said I don't really know SQLContainer so maybe there will be a better answer telling you that it is easy with the SQLContainer
For the Checkbox feature you could go display the name/product property as a CheckBox. With Icon and Caption it looks almost like you want it. See http://demo.vaadin.com/sampler/#ui/data-input/other/check-box and set an Icon. The semi-checked state could be done with css.
Hope this helps you finding the right solution for your task.
I'll admit that I'm a beginner with vaadin myself and there may be much better ways of doing this, but here's something I've mocked up which seems to work. It doesn't do everything you need but it might be a base to start from. Most importantly, for changes to be saved back into the database you'll need to update the SQLContainers when something in the container is changed.
import com.vaadin.data.Item;
import com.vaadin.data.Property;
import com.vaadin.data.util.HierarchicalContainer;
import com.vaadin.data.util.sqlcontainer.SQLContainer;
#SuppressWarnings("serial")
public class TwoTableHierarchicalContainer extends HierarchicalContainer {
private SQLContainer parentContainer;
private SQLContainer childContainer;
private String parentPrimaryKey;
private String childForeignKey;
public TwoTableHierarchicalContainer(SQLContainer parentContainer, SQLContainer childContainer,
String parentPrimaryKey, String childForeignKey) {
this.parentContainer = parentContainer;
this.childContainer = childContainer;
this.parentPrimaryKey = parentPrimaryKey;
this.childForeignKey = childForeignKey;
init();
}
private void init() {
for (Object containerPropertyIds : parentContainer.getContainerPropertyIds()) {
addContainerProperty(containerPropertyIds, Object.class, "");
}
for (Object containerPropertyIds : childContainer.getContainerPropertyIds()) {
addContainerProperty(containerPropertyIds, Object.class, "");
}
for (Object itemId : parentContainer.getItemIds()) {
Item parent = parentContainer.getItem(itemId);
Object newParentId = parent.getItemProperty(parentPrimaryKey).getValue();
Item newParent = addItem(newParentId);
setChildrenAllowed(newParentId, false);
for (Object propertyId : parent.getItemPropertyIds()) {
#SuppressWarnings("unchecked")
Property<Object> newProperty = newParent.getItemProperty(propertyId);
newProperty.setValue(parent.getItemProperty(propertyId).getValue());
}
}
for (Object itemId : childContainer.getItemIds()) {
Item child = childContainer.getItem(itemId);
Object newParentId = child.getItemProperty(childForeignKey).getValue();
Object newChildId = addItem();
Item newChild = getItem(newChildId);
setChildrenAllowed(newParentId, true);
setParent(newChildId, newParentId);
setChildrenAllowed(newChildId, false);
for (Object propertyId : child.getItemPropertyIds()) {
#SuppressWarnings("unchecked")
Property<Object> newProperty = newChild.getItemProperty(propertyId);
newProperty.setValue(child.getItemProperty(propertyId).getValue());
}
}
}
}
RIA Services is returning a list of Entities that won't allow me to add new items. Here are what I believe to be the pertinent details:
I'm using the released versions of Silverlight 4 and RIA Services 1.0 from mid-April of 2010.
I have a DomainService with a query method that returns List<ParentObject>.
ParentObject includes a property called "Children" that is defined as List<ChildObject>.
In the DomainService I have defined CRUD methods for ParentObject with appropriate attributes for the Query, Delete, Insert, and Update functions.
The ParentObject class has an Id property marked with the [Key] attribute. It also has the "Children" property marked with the attributes [Include], [Composition], and [Association("Parent_Child", "Id",
"ParentId")].
The ChildObject class has an Id marked with the [Key] attribute as well as a foreign key, "ParentId", that contains the Id of the parent.
On the client side, data is successfully returned and I assign the results of the query to a PagedCollectionView like this:
_pagedCollectionView = new PagedCollectionView(loadOperation.Entities);
When I try to add a new ParentObject to the PagedCollectionView like this:
ParentObject newParentObject = (ParentObject)_pagedCollectionView.AddNew();
I get the following error:
" 'Add New' is not allowed for this view."
On further investigation, I found that _pagedCollectionView.CanAddNew is "false" and cannot be changed because the property is read-only.
I need to be able to add and edit ParentObjects (with their related children, of course) to the PagedCollectionView. What do I need to do?
I was just playing around with a solution yesterday and feel pretty good about how it works. The reason you can't add is the source collection (op.Entities) is read-only. However, even if you could add to the collection, you'd still want to be adding to the EntitySet as well. I created a intermediate collection that takes care of both these things for me.
public class EntityList<T> : ObservableCollection<T> where T : Entity
{
private EntitySet<T> _entitySet;
public EntityList(IEnumerable<T> source, EntitySet<T> entitySet)
: base(source)
{
if (entitySet == null)
{
throw new ArgumentNullException("entitySet");
}
this._entitySet = entitySet;
}
protected override void InsertItem(int index, T item)
{
base.InsertItem(index, item);
if (!this._entitySet.Contains(item))
{
this._entitySet.Add(item);
}
}
protected override void RemoveItem(int index)
{
T item = this[index];
base.RemoveItem(index);
if (this._entitySet.Contains(item))
{
this._entitySet.Remove(item);
}
}
}
Then, I use it in code like this.
dataGrid.ItemsSource = new EntityList<Entity1>(op.Entities, context.Entity1s);
The only caveat is this collection does not actively update off the EntitySet. If you were binding to op.Entities, though, I assume that's what you'd expect.
[Edit]
A second caveat is this type is designed for binding. For full use of the available List operation (Clear, etc), you'd need to override a few of the other methods to write-though as well.
I'm planning to put together a post that explains this a little more in-depth, but for now, I hope this is enough.
Kyle
Here's a workaround which I am using:
Instead of using the AddNew, on your DomainContext you can retrieve an EntitySet<T> by saying Context.EntityNamePlural (ie: Context.Users = EntitySet<User> )
You can add a new entity to that EntitySet by calling Add() and then Context.SubmitChanges() to send it to the DB. To reflect the changes on the client you will need to Reload (Context.Load())
I just made this work about 15mins ago after having no luck with the PCV so I am sure it could be made to work better, but hopefully this will get you moving forward.
For my particular situation, I believe the best fit is this (Your Mileage May Vary):
Use a PagedCollectionView (PCV) as a wrapper around the context.EntityNamePlural (in my case, context.ParentObjects) which is an EntitySet. (Using loadOperation.Entities doesn't work for me because it is always read-only.)
_pagedCollectionView = new PagedCollectionView(context.ParentObjects);
Then bind to the PCV, but perform add/delete directly against the context.EntityNamePlural EntitySet. The PCV automatically syncs to the changes done to the underlying EntitySet so this approach means I don't need to worry about sync issues.
context.ParentObjects.Add();
(The reason for performing add/delete directly against the EntitySet instead of using the PCV is that PCV's implementation of IEditableCollectionView is incompatible with EntitySet causing IEditableCollectionView.CanAddNew to be "false" even though the underlying EntitySet supports this function.)
I think Kyle McClellan's approach (see his answer) may be preferred by some because it encapsulates the changes to the EntitySet, but I found that for my purposes it was unneccessary to add the ObservableCollection wrapper around loadOperation.Entities.
Many thanks to to Dallas Kinzel for his tips along the way!
I have implemented Linq-To-Sql..
Add necessary table in it...
after that linq class will automatically set property for field..
I implemented one class using ObservableCollection class.. and pass datacontextclass object in its constructor...
so after getting all data how to filter it?
public class BindBookIssueDetails : ObservableCollection
{
public BindBookIssueDetails(DataClasses1DataContext dataDC)
{
foreach (Resource_Allocation_View res in dataDC.Resource_Allocation_Views)
{
this.Add(res);
}
}
}
private BindBookIssueDetails bResource;
bResource = new BindBookIssueDetails(db);
_cmbResource.ItemSource=bResource;
Please Help me.
You can use CollectionViewSource and filter it. So that it affect only at the View(.XAML) side
ICollectionView collectionView = CollectionViewSource.GetDefaultView(bResource);
collectionView.Filter = new Predicate<object>(YourFilterFunction);
Check out this blog for more details. http://bea.stollnitz.com/blog/?p=31
I tried to use #Jobi's solution but for some reason I got an exception trying to fire FilterFunction.
So I used a slightly different approach. I cast CollectionViewSource's DefaultView to a BindingListCollectionView
myVS=(BindingListCollectionView)CollectionViewSource.GetDefaultView(sourceofdata);
and now I can construct an SQL-like filter string and apply it like that:
myVS.CustomFilter=myfilterstring;
I will still try to resolve my problem (I presume #Jobi's solution is more flexible).
I've got two combo's 'Make' and 'Model', they've got their SelectedValue properties bound to an Vehicle object with a ModelID and a MakeID.
Heres Model ...
<ComboBox DisplayMemberPath="Description" ItemsSource="{Binding Path=ModelSpecs}" SelectedValue="{Binding Path=Vehicle.ModelID}" SelectedValuePath="ID" />
A user can search for Vehicles in a seperate control and this swaps out the underlying Vehicle object. Everything works fine if your switching between vehicles of the same Make, however if the Make changes I go away to the database and reload the ModelSpec collection. The combo dosnt display the Model Description because the binding needs to be refreshed.
My current work-around is to add this at the end of the method thats reloading the Models - it works fine, but is not a particularly elegent solution.
var modelID = ViewModel.Vehicle.ModelID;
ViewModel.Vehicle.ModelID = string.Empty;
ViewModel.Vehicle.ModelID = modelID;
Basically I'm just triggering the INotifyPropertyChanged ...
private string _modelID;
public string ModelID
{
get { return _modelID; }
set
{
if (_modelID == value) return;
_modelID = value;
OnPropertyChanged("ModelID");
}
}
I can think of a couple of similar inelegant solutions - but there must be a better way?! Any help appreciated!
Just make ModelSpec collection observable (i.e. implement INotifyCollectionChanged yourself, or use ObservableCollection class for it).
Well, this is probably just another "inelegant" solution, but one more correct way would be to get the BindingExpression from the combo-box and call BindingExpression.UpdateSource.
Thanks for you assistance, in the end this did the trick and I prefer it to my first workaround.
It seems fine to me, but I guess others may gasp in horror? Please feel free to comment if so!
ModelSpecs is on my ManageVehicleViewModel so it dosnt seem that out of place to have the extra PropertyChanged call.
private IEnumerable<ModelSpec> _modelSpecs;
public IEnumerable<ModelSpec> ModelSpecs
{
get
{
return _modelSpecs;
}
set
{
if (_modelSpecs == value) return;
_modelSpecs = value;
OnPropertyChanged("ModelSpecs");
OnPropertyChanged("Vehicle");
}
}