[DefaultValue(DefaultBoolean.Default)]
[DXCategory("Data")]
public virtual DefaultBoolean EnableEditValueCollectionEditing { get; set; }

<DXCategory("Data")>
<DefaultValue(DefaultBoolean.Default)>
Public Overridable Property EnableEditValueCollectionEditing As DefaultBoolean

public partial class Form1 : Form {
    Employee person;
    List<Department> departments;
    public Form1() {
        InitializeComponent();
        person = new Employee {
            ID = 1,
            FullName = "John Smith",
        };
        departments = new List<Department> {
            new Department() { ID = 1, Name = "IT Department" },
            new Department() { ID = 2, Name = "Sales" },
            new Department() { ID = 3, Name = "Management" },
            new Department() { ID = 4, Name = "Support" },
            new Department() { ID = 5, Name = "Human Resources" },
            new Department() { ID = 6, Name = "Engineering" },
            new Department() { ID = 7, Name = "Shipping" },
        };
        // Populates binding sources with data.
        employeeBindingSource.DataSource = person;
        departmentBindingSource.DataSource = departments;

        leDepartments.Properties.DataSource = departmentBindingSource;
        leDepartments.Properties.ValueMember = "ID";
        leDepartments.Properties.DisplayMember = "Name";
        leDepartments.Properties.EditValueType = DevExpress.XtraEditors.Repository.LookUpEditValueType.ValueList;
        // Binds the editor's EditValue property to the Employee.Departments property.
        leDepartments.DataBindings.Add(new Binding("EditValue", employeeBindingSource, "Departments", true, DataSourceUpdateMode.OnPropertyChanged));
    }
}

public class Employee {
    public Employee() {
        Departments = new HashSet<int>();
    }
    public int ID { get; set; }
    public string FullName { get; set; }
    // Creates a read-only property of the HashSet<T> type.
    public HashSet<int> Departments { get; private set; }
}
public class Department {
    public int ID { get; set; }
    public string Name { get; set; }
}

Partial Public Class Form1
  Inherits Form

  Private person As Employee
  Private departments As List(Of Department)
  Public Sub New()
    InitializeComponent()
    person = New Employee With { .ID = 1, .FullName = "John Smith" }
    departments = New List(Of Department) From {
      New Department() With { .ID = 1, .Name = "IT Department" },
      New Department() With { .ID = 2, .Name = "Sales" },
      New Department() With { .ID = 3, .Name = "Management" },
      New Department() With { .ID = 4, .Name = "Support" },
      New Department() With { .ID = 5, .Name = "Human Resources" },
      New Department() With { .ID = 6, .Name = "Engineering" },
      New Department() With { .ID = 7, .Name = "Shipping" }
    }
    ' Populates binding sources with data.
    employeeBindingSource.DataSource = person
    departmentBindingSource.DataSource = departments

    leDepartments.Properties.DataSource = departmentBindingSource
    leDepartments.Properties.ValueMember = "ID"
    leDepartments.Properties.DisplayMember = "Name"
    leDepartments.Properties.EditValueType = DevExpress.XtraEditors.Repository.LookUpEditValueType.ValueList
    ' Binds the editor's EditValue property to the Employee.Departments property.
    leDepartments.DataBindings.Add(New Binding("EditValue", employeeBindingSource, "Departments", True, DataSourceUpdateMode.OnPropertyChanged))
  End Sub

  Public Class Employee
    Public Sub New()
      Departments = New HashSet(Of Integer)()
    End Sub
    Public Property ID() As Integer
    Public Property FullName() As String
    ' Creates a read-only property of the HashSet<T> type.
    Private privateDepartments As HashSet(Of Integer)
    Public Property Departments() As HashSet(Of Integer)
      Get
        Return privateDepartments
      End Get
      Private Set(ByVal value As HashSet(Of Integer))
        privateDepartments = value
      End Set
    End Property
  End Class
  Public Class Department
    Public Property ID() As Integer
    Public Property Name() As String
  End Class
End Class