Getting ready the ConditionalAppearance module infrastructure for custom options of the extended AppearanceAttribute (e.g., tooltip)

First of all, this piece of information is quite advanced, so be sure you are well-aware of the module's basic functions and main extensibility and customization points, at least through AppearanceController. If not, check out the related online documentation before reading further. 

Customer scenario

Would it be possible to add in the conditional appearance module the possibility to show a tooltip in the cell in listView when the 

condition is satisfied? (you get different color based on criteria and when you move to the cell a tooltip is shown telling you why the color is different ), example:

[C#]

[Appearance("CategoryColoredInListView", AppearanceItemType = "ViewItem", TargetItems = "Category", Criteria = "Category = 'Seafood'", Context = "ListView",FontColor = "Blue", Priority = 1, ToolTip="the tooltiptext!!!!")]

A more straightforward and convenient way to query data using LINQ with ObjectSpace

First of all, it is important to note that the capability to query data using LINQ has been available for a long time in the current version of XAF (or better said, in the underlying Entity Framework and XPO ORM libraries). So, this improvement in v15.2 is all about improving developer usability by exposing a helper method for the IObjectSpace interface representing one of the main XAF entities (learn more...). 

As noted in the corresponding SC ticket (from here you can also learn on the current solution):

The IObjectSpace interface now declares the following method:

[C#]IQueryable<T> GetObjectsQuery<T>(Boolean inTransaction = false);

This method is implemented in the XPObjectSpace, EFObjectSpace and NonPersistentObjectSpace classes. 

The inTransaction parameter has effect in XPO only and enables the mode in which querying a data store for objects includes all in-memory changes into query results.

In the NonPersistentObjectSpace, the GetObjectsQuery method casts the collection of objects created in the ObjectsGetting event to IQueryable and returns the result.

For XPObjectSpace, this method just returns a new XPQuery<T> from the underlying Session, while for the EFObjectSpace, the GetObjectsQuery method returns a new instance of ObjectQuery<T> with the help of the associated DbContext.

Here are a few usage examples from our unit tests (using the method-based query syntax):
EF:
IQueryable<Product> objectsQuery = objectSpaceB.GetObjectsQuery<Product>().Where(p => (p.Supplier.ID == supplier_A.ID));
Assert.AreEqual(5, objectsQuery.Count());
Assert.AreEqual(3, objectsQuery.Where(p => (p.Name == "A")).Count());
Assert.AreEqual(2, objectsQuery.Where(p => (p.Name == "B")).Count());

XPO:
IQueryable<TestObject> query = objectSpaceB.GetObjectsQuery<TestObject>();
Assert.AreEqual(5, query.Count());
Assert.AreEqual(3, query.Where(t => t.StringProperty == "A").Count());
Assert.AreEqual(2, query.Where(t => t.StringProperty == "B").Count());

I hope you will appreciate this minor improvement and it will save you from polluting your code by the casts to the XPObjectSpace/EFObjectSpace types to access the underlying ORM data context LINQ features.

How to place an Action in a different location programmatically

I think that many people know that they can control this visually by drag&drop under the ActionDesign | ActionToContainerMapping node in the Model Editor, but just a few know of the best code solution. A good scenario when it is necessary to handle this requirement in code is described by our customer in this Support Center ticket (more real user scenarios can be found here).

After receiving enough requests for this, we decided to put a full example solution in our docs. It is based on handling a single CustomizeContainerActions event of the built-in ActionControlsSiteController (or FillActionContainersController class, if your form template does not support the IActionControlsSite  interface).

Do not miss this new online documentation and hopefully, it will help you spend less effort on accomplishing your advanced business requirements in our framework.