public virtual object GetDataSourceRowByKeyValue(
    object keyValue
)

Public Overridable Function GetDataSourceRowByKeyValue(
    keyValue As Object
) As Object

using System;
using System.Windows.Forms;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;

public Form1() {
    InitializeComponent();
    List<Person> dsPersons = Person.Init();
    dataNavigator1.DataSource = dsPersons;
    textEdit1.DataBindings.Add(new Binding("EditValue", dsPersons, "Name"));
    lookUpEdit1.DataBindings.Add(new Binding("EditValue", dsPersons, "CityID"));
    lookUpEdit1.Properties.DataSource = CityInfo.Init();
    lookUpEdit1.Properties.ValueMember = "ID";
    lookUpEdit1.Properties.DisplayMember = "City";
}

public class Person {
    public string Name { get; set; }
    public int CityID { get; set; }
    static public List<Person> Init() {
        return new List<Person>() {
            new Person() { Name = "Carlos Gonzalez", CityID = 0 },
            new Person() { Name = "Mario Pontes", CityID = 5 },
            new Person() { Name = "Horst Kloss", CityID = 2 },
            new Person() { Name = "Martin Sommer", CityID = 3 },
            new Person() { Name = "Diego Roel", CityID = 3 },
            new Person() { Name = "Catherine Dewey", CityID = 4 }
        };
    }
}
public class CityInfo {
    int id;
    public CityInfo(int id) {
        this.id = id;
    }
    [Display(Order = -1)]
    public int ID { get { return id; } }
    public string City { get; set; }
    public string Country { get; set; }
    public string Region { get; set; }
    static public List<CityInfo> Init() {
        return new List<CityInfo>() {
            new CityInfo(0) { City = "Barquisimeto", Country = "Venezuela", Region = "Lara" },
            new CityInfo(1) { City = "Rio de Janeiro", Country = "Brazil", Region = "RJ" },
            new CityInfo(2) { City = "Cunewalde", Country = "Germany", Region = "" },
            new CityInfo(3) { City = "Madrid", Country = "Spain", Region = "" },
            new CityInfo(4) { City = "Charleroi", Country = "Belgium", Region = "" },
            new CityInfo(5) { City = "Sao Paulo", Country = "Brazil", Region = "SP" }
        };
    }
}

Imports System
Imports System.Windows.Forms
Imports System.Collections.Generic
Imports System.ComponentModel.DataAnnotations

Public Sub New()
    InitializeComponent()
    Dim dsPersons As List(Of Person) = Person.Init()
    dataNavigator1.DataSource = dsPersons
    textEdit1.DataBindings.Add(New Binding("EditValue", dsPersons, "Name"))
    lookUpEdit1.DataBindings.Add(New Binding("EditValue", dsPersons, "CityID"))
    lookUpEdit1.Properties.DataSource = CityInfo.Init()
    lookUpEdit1.Properties.ValueMember = "ID"
    lookUpEdit1.Properties.DisplayMember = "City"
End Sub

Public Class Person
    Public Property Name() As String
    Public Property CityID() As Integer
    Public Shared Function Init() As List(Of Person)
        Return New List(Of Person)() From {
            New Person() With {.Name = "Carlos Gonzalez", .CityID = 0},
            New Person() With {.Name = "Mario Pontes", .CityID = 5},
            New Person() With {.Name = "Horst Kloss", .CityID = 2},
            New Person() With {.Name = "Martin Sommer", .CityID = 3},
            New Person() With {.Name = "Diego Roel", .CityID = 3},
            New Person() With {.Name = "Catherine Dewey", .CityID = 4}
        }
    End Function
End Class
Public Class CityInfo
    Private fid As Integer
    Public Sub New(ByVal id As Integer)
        fid = id
    End Sub
    <Display(Order := -1)>
    Public ReadOnly Property ID() As Integer
        Get
            Return fid
        End Get
    End Property
    Public Property City() As String
    Public Property Country() As String
    Public Property Region() As String
    Public Shared Function Init() As List(Of CityInfo)
        Return New List(Of CityInfo)() From {
            New CityInfo(0) With {.City = "Barquisimeto", .Country = "Venezuela", .Region = "Lara"},
            New CityInfo(1) With {.City = "Rio de Janeiro", .Country = "Brazil", .Region = "RJ"},
            New CityInfo(2) With {.City = "Cunewalde", .Country = "Germany", .Region = ""},
            New CityInfo(3) With {.City = "Madrid", .Country = "Spain", .Region = ""},
            New CityInfo(4) With {.City = "Charleroi", .Country = "Belgium", .Region = ""},
            New CityInfo(5) With {.City = "Sao Paulo", .Country = "Brazil", .Region = "SP"}
        }
    End Function
End Class

if(props != null && (e.Value is int)) {
    object row = props.GetDataSourceRowByKeyValue(e.Value);
    if(row == null) {

If props IsNot Nothing AndAlso (TypeOf e.Value Is Integer) Then
    Dim row As Object = props.GetDataSourceRowByKeyValue(e.Value)
    If row Is Nothing Then