why doesn't CellValueChanged immediately appear in the expression datatable column in vb.net

Question

I'm trying to use CellValueChanged but why doesn't CellValueChanged immediately appear in the expression datatable column (MATERIALCOLORNAME) in vb.net

I have the code below

please guide me

Thanks

Private Sub CreateDataTable()
    If m_DataTable IsNot Nothing Then Return
    m_DataTable = New DataTable
    'Columns
    m_DataTable.Columns.Add("CODEPRODUCT", GetType(String))
    m_DataTable.Columns.Add("DESCRIPTION", GetType(String))
    m_DataTable.Columns.Add("COLORCODE", GetType(String))
    m_DataTable.Columns.Add("COLORNAME", GetType(String))
    m_DataTable.Columns.Add("MATERIAL", GetType(String))
    m_DataTable.Columns.Add("MATERIALCOLORNAME", GetType(String), "TRIM(IIF(MATERIAL Is Null Or SUBSTRING(MATERIAL, 1, 1) = '-', '', MATERIAL) + IIF(COLORNAME Is Null Or SUBSTRING(COLORNAME, 1, 1) = '-', '', ' ' + COLORNAME))")
End Sub

this is the code I use :

 Public m_DataTable As DataTable
 Public Function GetConnectionString2() As String
        Dim strCon As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\TRIAL.accdb;Persist Security Info=False;"
        Return strCon
    End Function

  Private Sub DataGridView1_CellValueChanged(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellValueChanged
        If e.RowIndex < 0 OrElse e.RowIndex < 0 Then Return
        Dim dgv = DirectCast(sender, DataGridView)
        'If Not dgv.IsCurrentCellDirty Then Return
        Dim row = dgv.Rows(e.RowIndex)
        Dim arrQueries() = {
            New With {
                .KeyCell = row.Cells("CODEPRODUCT"),
                .ValueCell = row.Cells("DESCRIPTION"),
                .Table = "PRODUCT"},
            New With {
                .KeyCell = row.Cells("SIZEPRODUCT"),
                .ValueCell = row.Cells("CATEGORY"),
                .Table = "SIZEPRODUCT"},
            New With {
                .KeyCell = row.Cells("COLORCODE"),
                .ValueCell = row.Cells("COLORNAME"),
                .Table = "COLORCODE"},
            New With {
                .KeyCell = row.Cells("COLORCODE"),
                .ValueCell = row.Cells("MATERIAL"),
                .Table = "COLORCODE"}
        }
        If Not arrQueries.Any(
            Function(q) q.KeyCell.OwningColumn Is dgv.Columns(e.ColumnIndex)) Then
            Return
        End If
        Using con = New OleDbConnection(GetConnectionString2()), cmd = con.CreateCommand()
            con.Open()
            For Each q In arrQueries
                If q.KeyCell.Value IsNot Nothing AndAlso
                    q.KeyCell.Value IsNot DBNull.Value AndAlso
                    Not String.IsNullOrEmpty(q.KeyCell.Value.ToString()) Then
                    cmd.CommandText = String.Format(
                        "SELECT {0} FROM {1} WHERE {2} = ?",
                        q.ValueCell.OwningColumn.Name, q.Table, q.KeyCell.OwningColumn.Name)
                    cmd.Parameters.Clear()
                    cmd.Parameters.Add("?", OleDbType.VarWChar).Value = q.KeyCell.Value
                    q.ValueCell.Value = cmd.ExecuteScalar()
                Else
                    q.ValueCell.Value = Nothing
                End If
            Next
        End Using
    End Sub
    End Sub
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        CreateDataTable()
        DataGridView1.DataSource = m_DataTable
    End Sub

this is a gif of the cellvaluechanged process