' ドロップダウンリストとしてCustomerIDを割り当てます
c1flexGrid1.Cols("CustomerID").ComboList = "AJK18F|BBK21D|AEF25N|BZD42S|AKC16G"

' ドロップダウンコンボボックスとしてCustomerIDを割り当て、パイプ文字"|"でリストを開始します
' c1flexGrid1.Cols("CustomerID").ComboList = "|AJK18F|BBK21D|AEF25N|BZD42S|AKC16G"      

Dim columnRange = New String() {"City", "Country"}
c1FlexGrid1.Cols("City").DataMap = New MultiColumnDictionary(dt, "City", columnRange, 0)

Dim dt As DataTable = New DataTable()
dt.Columns.Add("CustomerID", GetType(Integer))
dt.Columns.Add("ContactName", GetType(String))
dt.Columns.Add("Designation", GetType(String))
dt.Columns.Add("Country", GetType(Object))
dt.Columns.Add("City", GetType(String))

' サンプルデータ
dt.Rows.Add(1, "Maria Anders", "Sales Representative", "Spain", "Madrid")
dt.Rows.Add(2, "Ana Trujillo", "Sales Associate", "Mexico", "Monterrey")
dt.Rows.Add(3, "Antonio Moreno", "Owner", "Ireland", "Dublin")
dt.Rows.Add(4, "Thomas Hardy", "Sales Representative", "UK", "Bristol")
dt.Rows.Add(5, "Patricio Simpson", "Marketing Manager", "Germany", "Munich")
dt.Rows.Add(6, "Paolo Accorti", "Sales Representative", "Spain", "Barcelona")
dt.Rows.Add(7, "Martine Rancé", "Owner", "Mexico", "Puebla")
dt.Rows.Add(8, "Elizabeth Brown", "Marketing Manager", "UK", "London")
dt.Rows.Add(9, "Jaime Yorres", "Order Administrator", "Austria", "Vienna")
dt.Rows.Add(10, "Yvonne Moncada", "Marketing Manager", "Mexico", "Mexico")
dt.Rows.Add(11, "Helen Bennett", "Owner/Marketing", "Ireland", "Cork")
dt.Rows.Add(12, "Sergio Gutiérrezy", "Order Administrator", "Brazil", "Sao Paulo")
c1FlexGrid1.DataSource = dt

Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
    ' 顧客データを取得します
    Customers = GetCustomers()

    ' FlexGridにデータを入力します
    c1FlexGrid1.DataSource = Customers

    ' 国とその国コードのコレクションを作成します
    Dim countries As ObservableCollection(Of Country) = New ObservableCollection(Of Country)()
    countries.Add(New Country(1, "USA"))
    countries.Add(New Country(91, "India"))
    countries.Add(New Country(7, "Russia"))
    countries.Add(New Country(54, "Argentina"))
    countries.Add(New Country(81, "Japan"))
    countries.Add(New Country(380, "Ukraine"))
    countries.Add(New Country(98, "Iran"))
    countries.Add(New Country(45, "Denmark"))
    countries.Add(New Country(84, "Vietnam"))
    countries.Add(New Country(49, "Germany"))
    Dim countryBS As BindingSource = New BindingSource()
    countryBS.DataSource = countries

    ' C1Comboboxコントロールをインスタンス化して設定します 
    Dim countryCodeCombo As C1ComboBox = New C1ComboBox()
    countryCodeCombo.ItemsDataSource = countryBS

    ' 国コードと国名をマッピングするためにプロパティを設定します
    countryCodeCombo.ItemsDisplayMember = "CountryName"
    countryCodeCombo.ItemsValueMember = "CountryCode"
    countryCodeCombo.TextDetached = True
    countryCodeCombo.TranslateValue = True

    ' C1ComboboxをDiallingCode列のエディタとして設定します
    c1FlexGrid1.Cols("DiallingCode").Editor = countryCodeCombo
End Sub 

    Dim cb As ComboBox = CType(c1flexGrid1.Editor, ComboBox)
    cb.DropDownWidth = 250
    cb.DropDownHeight = 200 

    Dim comboBox As ComboBox = CType(c1flexGrid1.Editor, ComboBox)
    comboBox.BackColor = Color.Black
    comboBox.ForeColor = Color.White 

' コンボボックスに画像を入力します 
Dim itemsSource = New List(Of Flag)()
Dim imgFlag As ImageList = New ImageList()
imgFlag.Images.Clear()
Dim rsrSet = Resources.ResourceManager.GetResourceSet(CultureInfo.CurrentCulture, True, True)

For Each entry As DictionaryEntry In rsrSet
    Dim img = TryCast(entry.Value, Image)
    itemsSource.Add(New Flag(entry.Key.ToString(), img))
Next

itemsSource.Sort(New CompareFlag())

For Each entry In itemsSource
    imgFlag.Images.Add(entry.CountryName, entry.CountryFlag)
Next

countryCombo.ItemsImageList = imgFlag
countryCombo.ItemMode = ComboItemMode.HtmlPattern
countryCombo.HtmlPattern = "<div <div style='padding:0px'><img src='{CountryName}' style='padding-right:14px'>{CountryName}</div>"

' コンボボックスのドロップダウンに表示する国の数を設定します
countryCombo.MaxDropDownItems = 10

    Dim countryCombo As C1ComboBox = New C1ComboBox()
    countryCombo.DropDownStyle = DropDownStyle.DropDownList
    Dim countries As List(Of String) = New List(Of String) From {
        "USA",
        "Canada",
        "India",
        "Russia",
        "Japan",
        "Germany"
    }
    countries.Sort()
    countryCombo.ItemsDataSource = countries

    ' C1ComboboxをCountry列のエディタとして設定します
    c1FlexGrid1.Cols("Country").Editor = countryCombo      

Private Sub C1FlexGrid1_ComboCloseUp(ByVal sender As Object, ByVal e As C1.Win.C1FlexGrid.RowColEventArgs)
    MessageBox.Show("Selected Index：" & c1FlexGrid1.ComboBoxEditor.SelectedIndex & vbLf & "Selected Item：" + c1FlexGrid1.ComboBoxEditor.SelectedItem)
End Sub