Can't Access Custom Property

I created a new DataGridViewColumn type called DataGridViewGradeColumn.

Code:

---

Public Class DataGridViewGradeColumn
    Inherits DataGridViewTextBoxColumn
    Public Property AssignmentName As String
    Public Property AssignmentType As String
    Public Property AssingmentPerfectScore As Integer
End Class

---

Then I mad a DataGridView (called grd), added some columns to it, and tried to access on of the new column properties.

Code:

---

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        grd.RowCount = 5
    End Sub

    Private Sub btnNewColumn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNewColumn.Click
        grd.Columns().Add(New DataGridViewGradeColumn)
        Dim i As Integer = grd.ColumnCount - 1
        grd.Columns(i).Width = 30
        grd.Columns(i).DefaultCellStyle.Alignment = ContentAlignment.MiddleRight
        'grd.Columns(i).AssignmentName = "some text"
    End Sub

    Private Sub btnGetRowTotal_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGetRowTotal.Click
        Dim r As Integer = grd.CurrentRow.Index

        Dim t As Integer = 0
        For c As Integer = 2 To grd.ColumnCount - 1
            t = t + CInt(grd.Item(c, r).Value)
        Next
        MsgBox(t.ToString)
    End Sub
End Class

---

l
The new properties don't show up in intelisense.

How do I access my custom properties?

Moved From The CodeBank which is for posting code to share rather than asking questions. :)