I have a CellTable<UserProxy>. So in other words it manages directly entity proxies of my database entities. With that I use an AsyncDataProvider<UserProxy> that fetches the data using a request factory.
The cells of my columns are EditTextCell. And I added a FieldUpdater<UserProxy, String> to edit the values. Except here is my problem: if I update the value of the entity and save it immediately it works fine, but I don't know how I can differ the save to a click on a button later.
Basically, I want to implement the Apply-changes pattern (see: http://patterns.holehan.org/Review/ApplyChanges), so I want the user to be able to edit several values in the table and once he is done he can click the 'apply' button which will save all the changes.
So my idea for this was to change the value in the proxy entity without invoking save and then saving all modified entities in the clickhandler of the button.
But to make the change to a value in a proxy entity, I must call ctx.edit(user) first:
nameColumn.setFieldUpdater(new FieldUpdater<UserProxy, String>() {
#Override
public void update(int index, UserProxy object, String value) {
if (!value.equals(object.getName())) {
UserRequest ur = presenter.getClientFactory().getRequestFactory().getUserRequest();
ur.edit(object);
object.setName(value);
saveButton.setEnabled(true);
}
}
});
And this makes it impossible to save them afterwards in the clickhandler of the apply button:
private void saveModifications() {
List<UserProxy> items = cellTable.getVisibleItems();
for (UserProxy item : items) {
UserRequest ur = presenter.getClientFactory().getRequestFactory().getUserRequest();
ur.save(item).fire();
}
cellTable.setVisibleRangeAndClearData(cellTable.getVisibleRange(), true);
}
Because calling save(item) throws this exception: java.lang.IllegalArgumentException: Attempting to edit an EntityProxy previously edited by another RequestContext
How to avoid this without having to make yet another class representing the same entity?
You must use a single RequestContext instance where you edit() all your proxies. You can edit() several times the same proxy with no error and no overhead.
So:
store presenter.getClientFactory().getRequestFactory().getUserrequest() in a variable/field somewhere
in the FieldUpdaters, ctx.edit(object).setName(value) will enqueue the changes in the RequestContext; possibly put the UserProxy in a Set too for later reference
in saveModifications, loop over your proxies (possibly only those from the Set built on step 2) and ctx.save(item) and then at the end of the loop ctx.fire()
Related
i'm currently using GXT 3 to display elements in a Tree.
These elements are retrieved from database and identified in the Tree by their id (by that, I mean that the id is the ModelKeyProvider of my store).
I also made it possible for users to create objects locally in the tree with the following code:
private Tree<EntityDAO, String> tree;
private TreeStore<EntityDAO> store;
int count = 1;
// instanciation and irrelevant stuff
...
EntityDAO sel = tree.getSelectionModel().getSelectedItem();
EntityDAO child = new EntityDAO();
child.setId((long) count);
store.add(store.getParent(sel), child);
count++;
tree.setExpanded(sel, true);
tree.getSelectionModel().select(child, false);
As you can see, i set a temporary id (count) to my local object.
The issue occurs when I save my object in database. A permanent id is then set to my EntityDAO but when i try to set this id to my local object to sync it with the database, it doesn't work.
I've tried to modify the child id directly
child.setId(result);
tree.update(child);
I've tried to add a copy of my object with the proper id, and then to remove my object from the tree
EntityDAO newPR = child;
newPR.setId(result);
store.add(store.getParent(child), newPR);
store.remove(child);
But the display is never updated. Any clue?
Let's discuss about the first way you tried, the update method:
child.setId(result);
tree.update(child);
From the update method API state this :
Replaces the item that matches the key of the given item, and fires a
StoreUpdateEvent to indicate that this change has occurred. Any
changes to the previous model via it's record instance will be lost
and the record will be removed. This will not cause the sort or filter
to be re-applied to the object. Overrides: update(...) in Store
Parameters: item the new item to take its place in the Store.
So basically, the update method will replace the item inside the store that have the same key with your parameter. Your data have a new key that doesn't exist inside the store, that's why it doesn't effected anything to your tree display.
Second, let's discuss the create a copy of your object and set it with the proper id:
EntityDAO newPR = child;
newPR.setId(result);
store.add(store.getParent(child), newPR);
store.remove(child);
This way actually will work, but you only have one small problem. The first line of your code actually just give you a variable that have a reference to your old object (the child object), so whenever you remove the child, the newPR also removed. You should really create a new object using the constructor, here how I think you should do it:
EntityDAO newPR = new EntityDAO();
newPR.setId(result);
newPR.setOtherProperty(child.getOtherProperty());
// just copy all property of child to newPR
store.add(store.getParent(child), newPR);
store.remove(child);
Hope this can help you.
I have the following scenario:
I am using EF with Repository pattern and Unit Of Work from here
Then I extended my partial class and have created a Finder class which have GetAll and other methods.
You can this see below:
Below you can see that I am using a unit of work class with repositories of all classes to get the instance from the generic repository:
protected Repository<Category> _CategoryRepository;
public Repository<Category> CategoryRepository
{
get { return _CategoryRepository ?? (_CategoryRepository = new Repository<Category>(context)); }
}
So in this way I had different repositories and when getting an entity from db and updating it from a different context caused problems. So I used this method to use for context lifetime management. And it resolved that issue.
Now the problem I am facing is in the following code:
var cat = Instance.Category.GetSingle(c => c.CategoryID == 7);
var orignal = cat.CategoryName;
var expected = cat.CategoryName + " Test Catg Update";
cat.CategoryName = expected;
cat.Update(); //This doesn't actually update due to a validation in place (which is correct)
cat = Instance.Category.GetSingle(c => c.CategoryID == 7);
Assert.AreEqual(cat.CategoryName, expected);
When I use Update and I have some validators in it, and the Update fails (for example due to size of the string exceeds 15 characters). When I try to call GetSingle (2nd last line of above code) again, it brings me the same old record which is [cat.CategoryName + " Test Catg Update"]. Is this a normal way? If not how can this be fixed so I can reload the object from database.
Let me know if you need any other code or reference.
in your Update() method, if the validation fails, simply set the state of the entity to EntityState.Unchanged. Under the covers, changing the state of an entity from Modified to Unchanged first sets the values of all properties to the original values that were read from the database when it was queried, and then marks the entity as Unchanged. This will also reject changes to FK relationships since the original value of the FK will be restored.
You may be able to take advantage of the ObjectContext.Refresh() method to handle this as well. However, this is on the ObjectContext, so you would need a method to handle it in your UoW. The refresh method would be something like context.Refresh(RefreshMode.ServerWins, entity);
I'm using Entity Framework 5 with Code First. I've written a custom IDbConnectionFactory which I want to use for all the connections made by my DbContext class, so early on in the application's lifecycle, before any database work is done, I call
Database.DefaultConnectionFactory = new MyConnectionFactory();
However, MyConnectionFactory.CreateConnection is never called, which suggests to me that EF's changed it back - but the debugger shows that it's still a MyConnectionFactory after several queries have run. For some reason, it's just not using it.
My DbContext is initialised by passing the name of a connection string from the app.config file, and those connection strings do specify an explicit provider (as indeed they have to) so I'm wondering if that's causing a per-connection override of the connection factory based on the connection string. Does this happen and can I stop it without registering a completely new provider (although maybe that's not too hard to do?).
Whatever I see online about this (much obscured by the defaultConnectionFactory tag in various app.config examples) suggests you can just change it to an IDbConnectionFactory instance of your choice and it'll work, but mine isn't behaving.
The purpose of this is to allow me to run a particular set of SQL statements whenever a new connection is opened, so the second part of this question would be does anybody know a better way to do this?
I know it is not ideal but this worked for me:
public class DBBase : DbContext
{
public DBBase(string nameOrConnectionString)
: base(Database.DefaultConnectionFactory.CreateConnection(nameOrConnectionString), true)
{
}
// ...
}
You need to get the connection that you built for each call that you are wanting to use. For example using the following code.
private static void UsingCustomConnection()
{
using (var conn = Database.DefaultConnectionFactory.CreateConnection("YourDbName"))
{
using (var context = new YourContext(conn))
{
context.Destinations.Add(new Destination {Name = "Colorado"});
context.SaveChanges();
}
}
}
You will need to setup this in YourContext
public YourContext(DbConnection connection)
: base(connection, contextOwnsConnection: false)
{
}
I have CellTable with MultipleSelectionModel attached to it. After some modification of data the table has to be refreshed and new data has to be reloaded from server.
However I need to update checkboxes state for newly loaded data. So I am able to query selection boxes with selectionModel.getSelectedSet() - but now I need to find these objects in table and "check" them.
Because content of objects changes and since they are used as keys in Maps internally in GWT components- I was forced to write "wrapper" over these objects which uses only ID in equals/hashCode.
So basically I save selectedSet before firing event, then iterate over it and invoke setSelected method:
Set<T> selectedSet = selectionModel.getSelectedSet();
RangeChangeEvent.fire(table,...)
if (selectedSet != null)
for (T obj : selectedSet) {
selectionModel.setSelected(obj,true);
}
}
Is there any better approach?
This is what the ProvidesKey is for: create a ProvidesKey instance that returns the ID of your objects to be used as their keys, and pass that instance to your selection model when you build it:
MultiSelectionModel<X> selectionModel = new MultiSelectionModel<X>(new ProvidesKey<X>() {
#Override
public Object getKey(X item) {
return item.getId();
}
});
That way, you shouldn't have anything special to do with your selection model after retrieving updated data: push it to your table and it'll ask the selection model for each object whether it's selected or not, and the selection model will be able to answer based solely on the object's ID, therefore reusing the same selected set as before.
To facilitate control reuse we created a solution with three separate projects: a control library, Silverlight client, and ASP.NET backend. The control library has no reference to the RIA Services-generated data model classes so when it needs to interact with it, we use reflection.
This has worked fine so far but I've hit a bump. I have a DataGrid control where the user can select a row, press the 'delete' button, and it should remove the entity from the collection. In the DataGrid class I have the following method:
private void RemoveEntity(Entity entity)
{
// Use reflection to remove the item from the collection
Type sourceType = typeof(System.Windows.Ria.EntityCollection<>);
Type genericType = sourceType.MakeGenericType(entity.GetType());
System.Reflection.MethodInfo removeMethod = genericType.GetMethod("Remove");
removeMethod.Invoke(this._dataGrid.ItemsSource, new object[] { entity });
// Equivalent to: ('Foo' derives from Entity)
// EntityCollection<Foo> ec;
// ec.Remove(entity);
}
This works on the client side but on the domain service the following error gets generated during the Submit() method:
"The UPDATE statement conflicted with
the FOREIGN KEY constraint
"********". The conflict occurred in
database "********", table "********",
column '********'. The statement has
been terminated."
One thing I noticed is the UpdateFoo() service method is being called instead of the DeleteFoo() method on the domain service. Further inspection shows the entity is going into the ModifiedEntities ChangeSet instead of the RemovedEntities ChangeSet. I don't know if that's the problem but it doesn't seem right.
Any help would be appreciated, thanks,
UPDATE
I've determined that the problem is definitely coming from the reflection call to the EntityCollection.Remove() method. For some reason calling it causes the entity's EntityState property to change to EntityState.Modified instead of EntityState.Deleted as it should.
Even if I try to remove from the collection by completely circumventing the DataGrid I get the exact same issue:
Entity selectedEntity = this.DataContext.GetType().GetProperty("SelectedEntity").GetValue(this.DataContext, null) as Entity;
object foo = selectedEntity.GetType().GetProperty("Foo").GetValue(selectedEntity, null);
foo.GetType().InvokeMember("Remove", BindingFlags.InvokeMethod, null, foo, new object[] { entity });
As a test, I tried modifying the UpdateFoo() domain service method to implement a delete and it worked successfully to delete the entity. This indicates that the RIA service call is working correctly, it's just calling the wrong method (Update instead of Delete.)
public void UpdateFoo(Foo currentFoo)
{
// Original update implementation
//if ((currentFoo.EntityState == EntityState.Detached))
// this.ObjectContext.AttachAsModified(currentFoo, this.ChangeSet.GetOriginal(currentFoo));
// Delete implementation substituted in
Foo foo = this.ChangeSet.GetOriginal(currentFoo);
if ((foo.EntityState == EntityState.Detached))
this.ObjectContext.Attach(foo);
this.ObjectContext.DeleteObject(foo);
}
I've been researching a similar issue.
I believe the issue is you are calling remove with a reference for an EntityCollections within the DomainContext as the root reference rather than using the DomainContext itself as the root.
So...
ParentEntityCollection.EntityCollectionForTEntity.Remove(TEntity);
Produces the EntityState.Modified instead of EntityState.Deleted
Try instead...
DomainContext.EntityCollectionForTEntity.Remove(TEntity);
I think this will produce the result you are seeking.
Hope this helps.
What is the "column" in the "FOREIGN KEY constraint" error? Is this a field in the grid row and collection that coorosponds to that column? Is it possible that the entity you are trying to remove is a column in the row rather than the row itself which is causing an update to the row (to null the column) rather than to delete the row?
I read your update and looks like you've determined that the problem is the reflection.
Have you tried to take the reflection out of the picture?
As in:
private void RemoveEntity(Entity entity)
{
// Use reflection to remove the item from the collection
Type sourceType = typeof(System.Windows.Ria.EntityCollection<>);
Type genericType = sourceType.MakeGenericType(entity.GetType());
// Make sure we have the right type
// and let the framework take care of the proper invoke routine
if (genericType.IsAssignableFrom(this._dataGrid.ItemsSource.GetType()))
((Object) this._dataGrid.ItemsSource).Remove(entity);
}
Yes, I know it's ugly, but some times...
Edited to add
I've updated the code to remove the is keyword.
Now about using the object to make the call to the Remove method, I believe it might work due the late binding of it.