[VB.Net]
Public Class DynamicallyDropdownColumn
  Inherits Column
  Public Sub New(ByVal caption As String)
     MyBase.New(caption)
     EditorStyle = EditorStyle.DropDown
  End Sub
  
  Public Overrides Function GetValueList(ByVal node As NodeBase) As Object()
    'here you can return value list for dropdown
    Return New String() {"One", "Two", "Three"}
  End Function
End Class

Dim test As DynamicallyDropdownColumn
data = New Object() {attCode, attDesc, attIso, attPipe, attName, test}
Me.lstNameProp.Rows.Items.Add(New Node(data))

     _
    Public Class FileNameBasedData
        Public Class FileNameBasedDataEditor
            Inherits System.Drawing.Design.UITypeEditor
            Public Sub New()
                MyBase.New()
            End Sub

            Public Overloads Overrides Function GetEditStyle(ByVal context As ITypeDescriptorContext) As System.Drawing.Design.UITypeEditorEditStyle
                Return UITypeEditorEditStyle.DropDown
            End Function

            Public Overloads Overrides Function EditValue(ByVal context As ITypeDescriptorContext, ByVal provider As IServiceProvider, ByVal value As Object) As Object
                Dim _fileNameBasedData As FileNameBasedData = CType(value, frmControl.FileNameBasedData)
                If (Not _fileNameBasedData Is Nothing) Then
                    Dim _openFileDialog As New DropDownListColumn
                    _openFileDialog.Items.Add("hello")
                    _openFileDialog.Items.Add("hello1")
                    _openFileDialog.Items.Add("hello2")

                    Return _fileNameBasedData
                End If
                Return MyBase.EditValue(context, provider, value)
            End Function
        End Class
        Private _fileName As String
        Private Shared _defaultDirectory As String
        Shared Sub New()
            _defaultDirectory = String.Empty
        End Sub
        Public Sub New()
            _fileName = String.Empty
        End Sub
        Public Sub New(ByVal fileName As String)
            Me._fileName = fileName
        End Sub
        Public Shared Property DefaultDirectory() As String
            Get
                Return _defaultDirectory
            End Get
            Set(ByVal Value As String)
                _defaultDirectory = Value
            End Set
        End Property
        Public Overridable Property FileName() As String
            Get
                Return Me._fileName
            End Get
            Set(ByVal Value As String)
                If (_fileName  Value) Then
                    Me._fileName = Value
                End If
            End Set
        End Property
        Public Overridable ReadOnly Property IsEmpty() As Boolean
            Get
                Return Not (_fileName Is Nothing Or _fileName = String.Empty)
            End Get
        End Property
        Public Overrides Function ToString() As String
            Return IIf((Not Me.FileName Is Nothing), _fileName, String.Empty)
        End Function
    End Class

_
Public Class Class1
    ' Insert code here.
End Class 'MyClass