ขอคำแนะนำ ด้วยครับ รายละเอียด ด้านในครับ [มือใหม่หัดเขียน]

Public Class Country
	Public Property Name() As String
		Get
			Return m_Name
		End Get
		Set
			m_Name = Value
		End Set
	End Property
	Private m_Name As String
	Public Property Cities() As IList(Of City)
		Get
			Return m_Cities
		End Get
		Set
			m_Cities = Value
		End Set
	End Property
	Private m_Cities As IList(Of City)
	Public Sub New(_name As String)
		Cities = New List(Of City)()
		Name = _name
	End Sub
End Class

Dim countries As New List(Of Country)() From { _
	New Country("USA"), _
	New Country("Itly"), _
	New Country("Iran"), _
	New Country("UK") _
}

bindingSource1.DataSource = countries

comboBox1.DataSource = bindingSource1.DataSource

comboBox1.DisplayMember = "Name"
comboBox1.ValueMember = "Name"

        Dim comboBox As New ComboBox
        Dim daysOfWeek As String() = _
            New String() {"Monday", "Tuesday", "Wednesday", _
                          "Thursday", "Friday", "Saturday", _
                          "Sunday"}

        With comboBox
            .DataSource = daysOfWeek
            .Location = New System.Drawing.Point(12, 12)
            .Name = "comboBox"
            .Size = New System.Drawing.Size(166, 21)
            .DropDownStyle = ComboBoxStyle.DropDownList
        End With