Ways to Add a Business Class

• Aug 28, 2025
• 3 minutes to read

This topic describes how to add a business class to your application’s data model.

Code First

You can implement business classes from scratch or import them from external modules.

Implement a Business Class from Scratch

Refer to the following help topics for information on how to implement business model with your ORM:

• Implement Custom Business Classes (EF Core).

Import Classes from a Business Class Library or Module

Note

XPO:

When you add a class to the data model, all the referenced classes are also added.

EF Core:

When you add a class to the data model, you should register all the business class’ ancestors and referenced classes.

You can use existing classes from a Business Class Library or module. For this purpose, reference the assembly with these classes in a MySolution.Module project.

Import All Classes from an Assembly (In Code)

C#

using DevExpress.ExpressApp;
//...
public sealed class MySolutionModule : ModuleBase {
    public MySolutionModule() {
        //...
        AdditionalExportedTypes.AddRange(
            ModuleHelper.CollectExportedTypesFromAssembly(
            typeof(MyNamespace.MyModule).Assembly, ExportedTypeHelpers.IsExportedType));
    }
}

Import Select Classes from an Assembly (In Code)

C#

using DevExpress.ExpressApp;
using DevExpress.Persistent.BaseImpl;
//...
public sealed class MySolutionModule : ModuleBase {
    public MySolutionModule() {
        //...
        AdditionalExportedTypes.AddRange(
            new Type[] { typeof(Address), typeof(Note) });
    }
}

If you use EF Core, add all the new classes and their ancestors to the solution’s DbContext.

C#

using MySolutionModule.BusinessObjects;

namespace  MySolutionModule.BusinessObjects {
    public class MySolutionDbContext : DbContext {
        //...
        public DbSet<Address> Addresses { get; set; }
        public DbSet<Note> Notes { get; set; }
    }
}

Modify a Class from a Business Class Library or Module

You can modify a class from a Business Class Library or module in one of the following ways:

• Inherit from the class.

  Step-by-step instructions:

  • Implement Custom Business Classes (EF Core).
• Modify the information on the class loaded to the Application Model. For this purpose, invoke the Model Editor and navigate to the corresponding BOModel | <Class> node.

Model First (XPO)

You can use the XPO Data Model Designer to build your application data model in a visual designer and generate the code of underlying business classes.

Step-by-step instructions: How to: Create a Business Model in the XPO Data Model Designer.

Database First

If you already have a database with a set of tables, you can generate business classes that correspond to these tables.

Step-by-step instructions:

• XPO: How to: Generate XPO Business Classes for Existing Data Tables.
• EF Core: Generate EF Core Business Classes from an Existing Database for .NET Blazor and WinForms Applications (Database First)