How to: Add a New Detail Collection

• Jun 07, 2019
• 3 minutes to read

This document describes how to add a new detail collection to an application generated with the DevExpress Scaffolding Wizard. It supports editing detail collections (one-to-many relations). If such collections exist in a data source, the master object’s panel will contain additional GridControl controls displaying child objects.

This topic contains the following sections.

• Task Details
• Extend Model
• Regenerate ViewModels and Views
• Result

The complete sample project (the result of this current tutorial) is available at:

• http://www.devexpress.com/example=T111354

Task Details

In this topic, you will extend this example: http://www.devexpress.com/example=T322553. The example is built in the context of the UI Generation (Code First) tutorial.

The data model in this example contains the Department table.

C#

public class Department {
    public Department() {
        Courses = new HashSet<Course>();
    }
    public int DepartmentID { get; set; }
    public string Name { get; set; }
    public virtual ICollection<Course> Courses { get; set; }
}

VB.NET

Public Class Department
    Public Sub New()
        Courses = New HashSet(Of Course)()
    End Sub
    Public Property DepartmentID() As Integer
    Public Property Name() As String
    Public Overridable Property Courses() As ICollection(Of Course)
End Class

The Department table contains the Courses detail collection, which is shown in the UI.

This tutorial describes how to add a new detail collection into the Department table - Employees. The resulting UI is shown below.

Extend Model

Add the Employees property to the Department class.

C#

public class Department {
    public Department() {
        Courses = new HashSet<Course>();
        Employees = new HashSet<Employee>();
    }
    public int DepartmentID { get; set; }
    public string Name { get; set; }
    public virtual ICollection<Course> Courses { get; set; }
    public virtual ICollection<Employee> Employees { get; set; }
}

VB.NET

Public Class Department
    Public Sub New()
        Courses = New HashSet(Of Course)()
        Employees= New HashSet(Of Employee)()
    End Sub
    Public Property DepartmentID() As Integer
    Public Property Name() As String
    Public Overridable Property Courses() As ICollection(Of Course)
    Public Overridable Property Employees() As ICollection(Of Employee)
End Class

Regenerate ViewModels and Views

Now, when the model is updated, you can regenerate ViewModels and Views.

Open the Template Gallery.

Run the Scaffolding Wizard and follow its steps.

In the finish dialog, you can select which ViewModels and Views should be regenerated. In the current scenario, you need to select the ViewModel and View for the Department entity, and also all ViewModels and Views for related entities.

Result

If you run the application, you will see the Employee detail view has been added to the Department editing form.