How to: Create a Business Model in the XPO Data Model Designer

• The XPO Data Model Designer requires Visual Studio 2010 (or later).
• This designer can also be used to generate a data model for a legacy database (see How to: Generate XPO Business Classes for Existing Data Tables).

• Create a new XAF solution using the DevExpress v16.1 XAF Solution Wizard template.

• Right-click the BusinessObjects folder located in the module project and choose Add | New Item. In the invokedAdd New Item dialog, select the DXperience ORM Data Model Wizard template located in the DevExpresscategory. Set the new item‘s name to MySolutionDataModel.xpo and click Add. You will see that theMySolutionDataModel.xpo item is added, and the wizard dialog is invoked.

• In the invoked dialog, select Do not connect to a database and click Next, to skip the creation of a database connection using the XPO Data Model Wizard. The database connection is managed by XAF in your solution.

  

• As a result, an empty data model will be shown in the designer.

  

• To add a new business class, drag the XpObject item from the toolbox to the designer‘s surface.

  

• Focus the newly added object. In the Properties window, set the object‘s Name to Employee.

  

• To add a new persistent property, drag the Field item from the Toolbox to the Employee object.

  

• Focus the newly added field. In the Properties window, set the field‘s Name to FirstName.

  

  Note that the Column Type is String by default.

• Repeat the two previous steps to add the LastName property.

  

• Now add a field of a type other than string. Add the Birthday field, and set its Column Type to DateTime.

  

• Next, you will see how to add a calculated field. Drag the Persistent Alias item from the Toolbox to the Employeeobject.

  

• Focus the newly added persistent alias. In the Properties window, set Name to Full Name. Then, click the ellipsis button located to the right of the Expression setting. In the invoked Expression editor dialog, specify the[FirstName] + ‘ ‘ + [LastName] expression and click OK.

  

• To add another business class, drag the XpObject item from the toolbox to the designer‘s surface. Focus the newly added object. In the Properties window, set the object‘s Name to Task.

  

• Add the Subject and Description persistent properties of the string type using the approach described in theDesign the Employee Object section.

  

• Next, see how to apply attributes to persistent properties. Focus the Description field. In the Properties window, expand the DBType category, and set Size to Unlimited.

  

  As a result, the SizeAttribute will be applied to the Description property in the underlying code. The attribute‘s parameter will be set to SizeAttribute.Unlimited.

• Add the AssignedTo persistent property of the Employee type to the Task class. This property will represent the "one" part of the one-to-many association.

  

• In the Toolbox, focus the Association Object item. Draw a line from Employee to Task, to create the association.

  

• Save the changes and close the designer.

• In the Solution Explorer, expand the BusinessObjects\MySolutionDataModelCode folder. This folder contains the code generated by the designer. Open the Employee.cs (Employee.vb) file. Decorate the Employee class with theDefaultClassOptionsAttribute and ImageNameAttribute attributes to the Employee object. As a result, theEmployee object will be added to the Navigation System, and an icon from the built-in library will be associated with this object.

  C# VB

  using DevExpress.Persistent.Base;// ... [DefaultClassOptions, ImageName("BO_Employee")]public partial class Employee { public Employee(Session session) : base(session) { } public Employee() : base(Session.DefaultSession) { } public override void AfterConstruction() { base.AfterConstruction(); }}

• Open the Task.cs (Task.vb) file. Decorate the Task class with the DefaultClassOptions and ImageName attributes.

  C# VB

  using DevExpress.Persistent.Base;// ... [DefaultClassOptions, ImageName("BO_Task")]public partial class Task { public Task(Session session) : base(session) { } public Task() : base(Session.DefaultSession) { } public override void AfterConstruction() { base.AfterConstruction(); }}

Now you can run the Windows Forms and ASP.NET applications to see the result. These applications are completely based on the business model specified in the XPO Data Model Designer.

• Windows Forms

  

• ASP.NET