Resources in a Schedule
- 6 minutes to read
This topic introduces the concept of the Resources feature supported by the Scheduler Module, describes how scheduler events and resources are associated, and details how resources can be assigned to the scheduler events.
What is a Resource?
In real-life scheduling applications where one deals with a large amount of data being scheduled, appointments (scheduler events) are seldom processed “as is”, but are usually assigned to different resources. Resources can be of different kinds, and the decision as to what should be a resource in a particular scheduling application depends upon the specifics of the task performed by this particular application. The following are some examples of scheduling tasks, illustrating what can be an appointment and a resource in these tasks.
A Company.
Resource: Every employee in this company
Event: Any time interval which is spent by an employee to perform a particular task.
A Car Rental Agency.
Resource: Every car which is owned by this firm and available for rental.
Event: Any time interval when any of the firm’s cars are rented.
An Educational Center.
Resources: Every teacher who works at this center, or every classroom in this center.
Event: Any time interval when any of the teachers is delivering a lecture in any of the classrooms in the center.
Note
In the latter example, two kinds or resources are possible (teachers and rooms). However, the Scheduler controls do not allow events to belong to resources of a different nature. So, to display this data in a scheduling application, we suggest using two different Event List Views. One Event List View may be used to display teachers as resources, and another Event List View may be used to display rooms as resources, but both should be bound to the same data to assure consistency.
Association Between Resources and Scheduler Events
The Scheduler module works with classes that implement the DevExpress.Persistent.Base.General.IEvent interface and classes that implement the DevExpress.Persistent.Base.General.IResource interface. To support the Resources feature, the IEvent interface exposes the ResourceId property. This property specifies an XML string that lists the identifiers of the associated resources. In Windows Forms and ASP.NET Web Forms applications, the Scheduler module supports the ResourceSharing strategy where several Resources can be assigned to an Event. The following image demonstrates this concept:
Note
In ASP.NET Core Blazor applications, you cannot assign more than one resource to an event. If you assign multiple resources, XAF displays a warning message and treats the event as if it does not have any resources assigned to it.
The built-in DevExpress.Persistent.BaseImpl.Event class, which implements the IEvent interface, has a Many-to-Many association with the built-in DevExpress.Persistent.BaseImpl.Resource class, which implements the IResource interface. All Resource objects from the Event’s Resources collection are listed in the Event’s IEvent.ResourceId property.
Use Built-in Event and Resource Classes
To use the built-in Event and Resource classes in your application, add the Event class to a module in your solution as described in the following topic: Ways to Add a Business Class. The built-in Resource class is added automatically with the Event class. If you use the DevExpress.Persistent.BaseImpl.EF.Event (Entity Framework Core) or DevExpress.Persistent.BaseImpl.Event (XPO) class’ descendant, the built-in DevExpress.Persistent.BaseImpl.EF.Resource (Entity Framework Core) or DevExpress.Persistent.BaseImpl.Resource (XPO) class is added to the process of automatic UI generation as well. This allows you to have an extended Event class, but use the inherited association with the Resource class.
At runtime, you can create and display Resource objects by displaying the Resource List View and Detail View. In addition, you can add the required resources to an Event’s Resources collection in the Event Detail View:
- ASP.NET Core Blazor
- Windows Forms
- ASP.NET Web Forms
Resources are also displayed in Event List Views. The following image shows how a collection of two Resources (1 and 2) is displayed in an Event List View:
- ASp.NET Core Blazor
- Windows Forms
- ASP.NET Web Forms
In Windows Forms and ASP.NET Web Forms applications, use the Resource Navigator in the bottom right area of the Scheduler Control. It allows you to scroll through resources and change the number of resources displayed on the screen at a time.
Use a Custom Resource Class
To be supported by the Scheduler module, a Resource class must implement the DevExpress.Persistent.Base.General.IResource interface. The built-in DevExpress.Persistent.BaseImpl.EF.Resource (Entity Framework Core) and DevExpress.Persistent.BaseImpl.Resource (XPO) class from the Business Class Library implements this interface. A custom Resource class must implement this interface as well. To implement a custom Resource class, inherit from the built-in Resource class or implement the IResource interface from scratch. You can find the sources of the built-in Resource class at the following location:
- Entity Framework Core: %PROGRAMFILES%\DevExpress 23.2\Components\Sources\DevExpress.Persistent\DevExpress.Persistent.BaseImpl.EFCore\Resource.cs
- XPO: %PROGRAMFILES%\DevExpress 23.2\Components\Sources\DevExpress.Persistent\DevExpress.Persistent.BaseImpl.Xpo\Resource.cs
Since the built-in Event class is associated with the built-in Resource class, you have to implement a custom Event class to associate it with the custom Resource class. For this purpose, use the sources of the built-in Event class. You can find them at the following location:
- Entity Framework Core: %PROGRAMFILES%\DevExpress 23.2\Components\Sources\DevExpress.Persistent\DevExpress.Persistent.BaseImpl.EFCore\Event.cs
- XPO: %PROGRAMFILES%\DevExpress 23.2\Components\Sources\DevExpress.Persistent\DevExpress.Persistent.BaseImpl.Xpo\Event.cs
The type of the objects that serve as a resource data source for the Scheduler List Editor must be set to the IModelListViewScheduler.ResourceClass property of the Application Model‘s Views | <ListView> node:
The Application Model is extended with this property by the Scheduler module. If you have a single class that implements the IResource interface in your application, this class is assigned to this property automatically. If you have several classes that implement the IResource interface, you can assign any of them to this property. Otherwise, XAF selects the first found type.
Tip
For more information on how to implement a custom resource class, refer to the following example: XAF - Create Custom Event and Resource Classes for XAF Scheduler
Filter Resources in Scheduler
Use the SchedulerListEditorBase.ResourceDataSourceCreating event to specify a resources data source.
Use the SchedulerListEditorBase.ResourceDataSourceCreated event to filter the created resources data source.
using DevExpress.ExpressApp.Scheduler;
using DevExpress.ExpressApp;
using DevExpress.Persistent.Base.General;
using DevExpress.Data.Filtering;
namespace YourApplicationName.Blazor.Server.Controllers {
public class FilterResourcesController : ObjectViewController<ListView, IEvent> {
protected override void OnActivated() {
base.OnActivated();
SchedulerListEditorBase editor = (SchedulerListEditorBase)View.Editor;
editor.ResourceDataSourceCreating += Editor_ResourceDataSourceCreating;
editor.ResourceDataSourceCreated += editor_ResourceDataSourceCreated;
}
private void Editor_ResourceDataSourceCreating(object sender, ResourceDataSourceCreatingEventArgs e) {
e.DataSource = ObjectSpace.CreateCollection(typeof(DevExpress.Persistent.BaseImpl.EF.Resource));
}
private void editor_ResourceDataSourceCreated(Object sender, ResourceDataSourceCreatedEventArgs e) {
var resourcesDataSource = e.DataSource;
var filterCriteria = new BinaryOperator(nameof(IResource.Caption), "Resource1");
((DevExpress.ExpressApp.EFCore.EFCoreCollection)resourcesDataSource).Criteria = filterCriteria;
}
}
}