ObjectSpace

BaseObjectSpace Members

A base class for the classes that implement the IObjectSpace interface.

 Public Constructors

Show: Inherited

	Name	Description
	BaseObjectSpace	Creates a new instance of the BaseObjectSpace class.

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 Public Properties

Show: Inherited

	Name	Description
	CanFilterByNonPersistentMembers	For internal use.
	Connection	Gets the connection to the underlying data source.
	Database	Gets the name of the database.
	IsCommitting	Indicates whether the Object Space is currently committing the changes made to its object(s).
	IsConnected	Indicates whether the BaseObjectSpace is connected to the database.
	IsDeleting	Indicates whether the current Object Space is about to delete an object(s).
	IsDisposed	Gets a value indicating whether an Object Space has been disposed of.
	IsModified	Specifies whether objects belonging to the current Object Space are modified.
	IsReloading	Gets a boolean value indicating whether or not the Object Space is reloading.
	LockingCheckEnabled	Specifies whether or not the additional locking check is performed.
	ModifiedObjects	Returns a collection of objects that have been created, modified or deleted in the current object context.
	NonPersistentChangesEnabled	Specifies whether the BaseObjectSpace is marked as modified (see IsModified) when a non-persistent property is changed.
	Owner	Specifies the View owning the current Object Space.
	TypesInfo	Gets information on the business classes added to the Application Model (see IModelBOModel).

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 Public Methods

Show: Inherited

	Name	Description
	ApplyCriteria	Filters a particular collection on the server side.
	ApplyFilter	Filters a particular collection on the client side.
	CanApplyCriteria	Indicates whether collections of a particular type can be filtered on the server side.
	CanApplyFilter	Indicates whether a particular collection can be filtered on the client side.
	CanInstantiate	Indicates whether instances of a particular type can be created.
	CommitChanges	Saves all the changes made to the persistent objects belonging to the current Object Space to the database.
	Contains	Indicates whether a specified object belongs to the current Object Space.
	ConvertExpressionsStringToExpressionsList	Returns the list of DataViewExpression objects converted from the passed semicolon-separated expressions list.
	ConvertSortingToString	Returns the string representation of a given sort list.
	ConvertStringToSorting	Converts the sorting string into the sorting list.
	CreateCollection	Overloaded. Creates and initializes a collection of objects of the specified type.
	CreateDataView	Overloaded. Returns a list of data records retrieved from a database without loading complete business classes (a data view). Values in each data record can be obtained from specific business class properties directly, or be evaluated by the database server using complex expressions.
	CreateInstantFeedbackCollection
	CreateNestedObjectSpace	Creates a nested Object Space.
	CreateObject	Creates an object of the specified type.
	CreateObject	Creates an object of the type designated by the specified generic type parameter.
	CreateParseCriteriaScope	Used when parsing a CriteriaOperator represented by a string and containing persistent objects.
	CreateServerCollection	Creates and initializes a new instance of the EFServerCollection or DevExpress.Xpo.XPServerCollectionSource class with criteria-specific options.
	Delete	Overloaded. Marks the specified persistent object and its aggregated objects as deleted from persistent storage.
	Dispose	Releases all resources used by an BaseObjectSpace object.
	EnableObjectDeletionOnRemove	Enables/disables the deletion of persistent objects from the data source when they are removed from the specified collection.
	Equals	Determines whether the specified System.Object instances are considered equal. (Inherited from System.Object)
	Equals	Determines whether the specified System.Object is equal to the current System.Object. (Inherited from System.Object)
	Evaluate	Evaluates the specified criteria for business objects of the given type.
	FindObject	Overloaded. Searches for the first object of the specified type, matching the specified criteria.
	FindObject	Overloaded. Searches for the first object of the type designated by the specified generic type parameter, matching the specified criteria.
	GetAssociatedCollectionCriteria	Returns the criteria applied to a specific object's associated collection property.
	GetCollectionObjectType
	GetCollectionSorting	Returns the sort settings for a particular collection.
	GetCriteria	Returns the criteria used to filter a particular collection on the server side.
	GetDisplayableProperties	Gets the properties considered visible by the specified collection.
	GetEvaluatorContextDescriptor	Creates an instance of the EvaluatorContextDescriptor that is used to supply metadata on the specified type to the ExpressionEvaluator objects.
	GetExpressionEvaluator	Overloaded. Creates an ExpressionEvaluator object that is used to evaluate whether objects of the specified type satisfy a particular criteria.
	GetFilter	Returns the criteria used to filter a particular collection on the client side.
	GetHashCode	Serves as a hash function for a particular type. System.Object.GetHashCode is suitable for use in hashing algorithms and data structures like a hash table. (Inherited from System.Object)
	GetIntermediateObjectReferences	For internal use.
	GetKeyPropertyName	Gets the name of the specified type's key property.
	GetKeyPropertyType	Gets the key property type of the specified business type.
	GetKeyValue	Overloaded. Returns the key property's value of the specified object.
	GetKeyValue	Overloaded. Returns the key property's value of the specified persistent object.
	GetKeyValueAsString	Overloaded. Returns the key property's value of the specified object, converted to a string representation.
	GetKeyValueAsString	Overloaded.
	GetObject	Retrieves an object that corresponds to a specific object from another Object Space or to a specific record from a data view created by the IObjectSpace.CreateDataView method.
	GetObject	Retrieves an object from another Object Space to the current Object Space. The returned object is cast by the type designated by the specified generic type parameter.
	GetObjectByHandle	Returns the object with the specified handle.
	GetObjectByKey	Returns the persistent object that has the specified value for its key property.
	GetObjectByKey	Returns a persistent object of the type designated by the specified generic type parameter, with the specified value for its key property.
	GetObjectHandle	Returns an object's handle.
	GetObjectKey	Converts the key property value string representation into its actual type.
	GetObjects	Overloaded. Returns an IList collection of objects of the specified type, retrieved to the current Object Space and filtered according to the specified criteria.
	GetObjects	Overloaded. Returns an IList collection of objects of the specified type, retrieved to the current Object Space and filtered according to the specified criteria.
	GetObjectsCount	Returns the number of objects specified.
	GetObjectsCriteria	Constructs a criteria that can be used to select the specified list of business objects.
	GetObjectsQuery	Gets a queryable data structure that provides functionality to evaluate queries against a specific business object type.
	GetObjectsToDelete	Returns a collection of persistent objects that will be deleted when the current transaction is committed, including objects that will be deleted in the parent transaction(s), optionally.
	GetObjectsToSave	Returns a collection of persistent objects that will be saved when the current transaction is committed, including objects that will be saved in the parent transaction(s), optionally.
	GetObjectType	Returns the type of the specified business object.
	GetTopReturnedObjectsCount	Returns the maximum number of objects to be retrieved by the specified collection from a data store.
	GetType	Gets the System.Type of the current instance. (Inherited from System.Object)
	IsCollectionLoaded	Indicates whether a particular collection is loaded with objects from the database.
	IsDeletedObject	Indicates whether the specified persistent object is deleted from the database.
	IsDeletionDeferredType	Returns a value that indicates if the deferred deletion is enabled for persistent objects of a given type.
	IsDisposedObject	Determines whether an object has been disposed of.
	IsIntermediateObject	For internal use.
	IsKnownType	Returns the boolean value indicating whether or not the specified type is known by the BaseObjectSpace.
	IsNewObject	Indicates whether a specified object has been created but has not been saved to the database.
	IsObjectDeletionOnRemoveEnabled	Indicates whether the deletion of persistent objects from the data source when they are removed from the specified collection is enabled.
	IsObjectFitForCriteria	Overloaded. Specifies whether a particular object satisfies the specified criteria.
	IsObjectToDelete	Indicates whether the specified object has been deleted but not committed in the current object context or the transaction currently in progress.
	IsObjectToSave	Indicates whether the specified object has been added, deleted or modified, but not committed in the current object context or the transaction currently in progress.
	ObjectKeyValuesEqual
	ParseCriteria	Tries to convert the specified string representation of an expression to its DevExpress.Data.Filtering.CriteriaOperator equivalent.
	ReferenceEquals	Determines whether the specified System.Object instances are the same instance. (Inherited from System.Object)
	Refresh	Updates the persistent objects belonging to the current Object Space.
	ReloadCollection	Clears the specified collection.
	ReloadObject	Updates the specified object in the current Object Space with data from the data source.
	RemoveFromModifiedObjects	Removes the specified object from the object context or the list of objects to be committed.
	Rollback	Cancels the changes made to the persistent objects belonging to the current Object Space.
	SetCollectionSorting	Applies the specified sorting to a given collection.
	SetDisplayableProperties	Changes the properties considered visible by a particular collection.
	SetModified	Overloaded. Sets the state of the specified object to be Modified.
	SetPrefetchPropertyNames
	SetTopReturnedObjectsCount	Sets the maximum number of objects that can be retrieved from the specified collection in a data store.
	ToString	Returns a System.String that represents the current System.Object. (Inherited from System.Object)

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 Public Fields

Show: Inherited

	Name	Description
	CompositeKeyPropertyType

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 Public Events

Show: Inherited

	Name	Description
	Committed	Raised after saving changes made to persistent objects belonging to the current Object Space to the database.
	Committing	Occurs before saving the persistent objects belonging to the current Object Space to the database.
	ConfirmationRequired	Occurs when performing refresh or rollback operations with the current Object Space's persistent objects.
	Connected	Occurs after a connection to a database has been established.
	CustomCommitChanges	Replaces the default process for committing changes made to persistent objects with a custom one.
	CustomDeleteObjects	Occurs to replace the default process of deleting persistent objects with a custom one.
	CustomRefresh	Occurs to replace the default process of refreshing persistent objects with a custom one.
	CustomRollBack	Occurs to replace the default process of persistent objects rollback with a custom one.
	Disposed	Occurs before an Object Space is disposed of.
	ModifiedChanged	Occurs when the current Object Space's IsModified state is changed.
	ObjectChanged	Raised when a persistent object is created, changed or deleted.
	ObjectDeleted	Occurs after the specified objects have been deleted.
	ObjectDeleting	Occurs when the specified objects are about to be deleted.
	ObjectEndEdit	Occurs after ending an edit operation taking place on the specified object.
	ObjectReloaded	Occurs after an object has been reloaded from the database.
	ObjectSaved	Occurs after saving changes made to a specified persistent object to the database.
	ObjectSaving	Raised before saving changes made to a specified persistent object to the database.
	Refreshing	Occurs before refreshing the current Object Space's persistent objects.
	Reloaded	Occurs when the Rollback or Refresh method is called.
	RollingBack	Occurs before rolling back the changes made to the current Object Space's persistent objects.

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 See Also

BaseObjectSpace Class
DevExpress.ExpressApp Namespace

Pop-up Window

Add an Action that Displays a Pop-up Window

In this lesson, you will learn how to create an Action that shows a pop-up window. This type of Action is useful when you want a user to input several parameters in a pop-up dialog before an Action is executed.

Note

Before proceeding, take a moment to review the following lessons.

• Set a Many-to-Many Relationship (XPO/EF)
• Add a Simple Action

 Create a Controller and a PopupWindowShowAction

• Add a new View Controller to the MySolution.Module project, as described in the Add a Simple Action lesson. Name it PopupNotesController.
• Right-click the MySolution.Module | Controllers | PopupNotesController.cs (PopupNotesController.vb) file, and choose View Designer to invoke the Designer.
  
• Drag the PopupWindowShowAction component from the DX.17.2: XAF Actions tab to the Designer. In the popupWindowShowAction1 "Properties" window, set the Name and Id properties to "ShowNotesAction", and set the Caption property to "Show Notes". Set the Category property to "Edit". This property specifies the Action group to which the current Action belongs. All Actions within a single group are displayed together sequentially in a UI.
  
• To activate the PopupNotesController for DemoTask Detail Views only, set the Controller's ViewController.TargetObjectType property to MySolution.Module.DemoTask, and set the ViewController.TargetViewType to DetailView.
  

 Specify the Popup List View

Focus the ShowNotesAction component. In the Properties window, switch to the Events view. Double-click the CustomizePopupWindowParams event, add the "using" ("Imports" in VB) directive according to your ORM, and replace the auto-generated event handler code with the following code.

C# VB

using DevExpress.Persistent.BaseImpl; //For XPO  using DevExpress.Persistent.BaseImpl.EF; //For EF  // ...  private void ShowNotesAction_CustomizePopupWindowParams(object sender, CustomizePopupWindowParamsEventArgs args) { IObjectSpace objectSpace = Application.CreateObjectSpace(typeof(Note)); string noteListViewId = Application.FindLookupListViewId(typeof(Note)); CollectionSourceBase collectionSource = Application.CreateCollectionSource(objectSpace, typeof(Note), noteListViewId); args.View = Application.CreateListView(noteListViewId, collectionSource, true); //Optionally customize the window display settings.  //args.Size = new System.Drawing.Size(600, 400);  //args.Maximized = true;  //args.IsSizeable = false;  }

For details on this event, refer to the PopupWindowShowAction.CustomizePopupWindowParams topic. The code above will create the Notes List View when generating the pop-up window.

To create a List View, use the XafApplication object again (as you did in the previous lesson). In the code above, the XafApplication helps you find the ID of the required List View in the Application Model. Note that a collection source for the List View is created in a separate Object Space. To create the Object Space, use XafApplication again.

 Handle the Execute Event

In the Controller's Designer, switch to the Events view in the Properties window with the Action's properties. Double-click the Execute event, add the "using" ("Imports" in VB) directive and replace the auto-generated event handler code with the following code.

C# VB

using MySolution.Module.BusinessObjects; // ...  private void ShowNotesAction_Execute(object sender, PopupWindowShowActionExecuteEventArgs args) { DemoTask task = (DemoTask)View.CurrentObject; foreach(Note note in args.PopupWindowViewSelectedObjects) { if(!string.IsNullOrEmpty(task.Description)) { task.Description += Environment.NewLine; } task.Description += note.Text; } if(((DetailView)View).ViewEditMode == ViewEditMode.View) { View.ObjectSpace.CommitChanges(); } }

The Execute event is raised when clicking the OK button in the pop-up window. When the handler above is executed, the Text property value of the selected Note object will be appended to the Task.Description property value.

In this code, access the object selected in the pop-up window by using the event handler's PopupWindowShowActionExecuteEventArgs.PopupWindowViewSelectedObjects parameter.

To refresh the editor representing the modified Description property, first find its PropertyEditor in the current View's CompositeView.Items collection using the CompositeView.FindItem method. To update the value displayed by the Property Editor's editor, call the PropertyEditor.ReadValue method.

In ASP.NET Web applications, Detail Views are displayed in View and Edit modes. When the ShowNotes Action is activated for a DemoTask Detail View that is in View mode, the changes made to the DemoTask.Description property should be saved to the database. For this purpose, the CommitChanges method of the current View's ObjectSpace is called. When you use the ShowNotes Action in a DemoTask Detail View that is in Edit mode, the changes can be saved or rolled back via the corresponding built-in Actions.

 Add Notes to the UI

• To add the Note business class to the UI construction process, add it to the Application Model.
• If your ORM is Entity Framework, you should register the Note type in DbContext before proceeding to the next step. Edit the BusinessObjects\MySolutionDbContext.cs file as shown below.

  C# VB

  public class MySolutionDbContext : DbContext { //...  public DbSet Notes { get; set; } }

• To add the Note business class from the Business Class Library use the Module Designer. Double-click the Module.cs (Module.vb) file within the MySolution.Module project. The Exported Types section of the designer lists the business classes that can be added.
  • If you are using XPO:
    Locate the Referenced Assemblies | DevExpress.Persistent.BaseImpl.v17.2 | Note node.
  • If you are using Entity Framework:
    Locate the Referenced Assemblies | DevExpress.Persistent.BaseImpl.EF.v17.2 | Note node.
  Select this node and press the SPACEBAR, or right-click it and choose Use Type in Application in the invoked context menu.
  
• Build the project.
  
Note
To create Note objects, you should add the Note item to the New Action's items. To do this, perform the steps demonstrated in the Add an Item to the New Action lesson.
To access the existing Note objects, add the Note item to the ShowNavigationItem Action's items (displayed by the navigation control). To do this, perform the steps demonstrated in the Add an Item to the Navigation Controllesson.

 Result

Run the WinForms or ASP.NET application. Create several Note objects via the New Action. Select the Task item in the navigation control. Double-click one of the listed Task objects. In the invoked detail form, find the Show Notes toolbar button that represents the implemented Action. Click this button, which will invoke a pop-up window. Select a Note object in the list and click OK. Check to see that the Task.Description property value has been changed.

Tip

For an example of how to create and show a Detail View, refer to the How to: Create and Show a Detail View of the Selected Object in a Popup Window topic.

You can view the code demonstrated in this tutorial in the MySolution.Module | Controllers | PopupNotesController.cs (PopupNotesController.vb) file of the Main Demo installed with XAF. The MainDemo application is installed in %PUBLIC%\Documents\DevExpress Demos 17.2\Components\eXpressApp Framework\MainDemo by default. The ASP.NET version of this demo is available online at http://demos.devexpress.com/XAF/MainDemo/.

Next Lesson: Add an Action with Option Selection

 See Also

Ways to Implement Business Logic
BaseObjectSpace.SetModified
Actions
Controllers
PopupWindowShowAction
DialogController.SaveOnAccept