Operation did not succeed because the program cannot commit or quit a cell value change in VB.Net

Dear Sir,

I have an error `Operation did not succeed because the program cannot commit or quit a cell value change. `

If I comment out code CellValidating event in form2.

then the error does not appear but I use one form 'form2' as a view and new transaction please guide me.

Thanks

code in form1

Imports System.ComponentModel
Imports System.Configuration
Imports System.Data.OleDb
Imports System.Reflection
Imports Dapper

Public Class Form1
    Private InvoicesService As New InvoicesService()
    Private bindingSource As BindingSource = Nothing
    Private _criteriasBindingList As New BindingList(Of Invoices)()
    Public Sub New()
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.
        ' To reduce the flickering...
        DataGridView1.GetType().
    GetProperty("DoubleBuffered",
                BindingFlags.Instance Or BindingFlags.NonPublic).
    SetValue(DataGridView1, True)
        DataGridView1.ReadOnly = True
        LoadData()
        DataGridView1.Columns.Add(New DataGridViewLinkColumn With {
    .Name = "Colview",
    .Text = "👁‍🗨",
    .HeaderText = "",
    .UseColumnTextForLinkValue = True,
    .ActiveLinkColor = System.Drawing.Color.MediumAquamarine,
    .LinkColor = System.Drawing.Color.MediumAquamarine,
    .VisitedLinkColor = System.Drawing.Color.MediumAquamarine,
    .LinkBehavior = LinkBehavior.NeverUnderline,
    .ReadOnly = True,
    .DataPropertyName = "Colview",
    .Width = 20})
    End Sub
    Private Sub LoadData()
        Dim list = InvoicesService.GetInvoices()
        _criteriasBindingList = New BindingList(Of Invoices)(CType(list, IList(Of Invoices)))
        bindingSource = New BindingSource With {.DataSource = _criteriasBindingList}
        DataGridView1.DataSource = bindingSource
    End Sub
    Private Function GetSELECT() As Invoices
        Return If(DataGridView1.SelectedCells.Count = 0, Nothing, TryCast(DataGridView1.SelectedCells(0).OwningRow.DataBoundItem, Invoices))
    End Function
    Private Sub DataGridView1_CellContentClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick
        Dim dgv = DirectCast(sender, DataGridView)
        Dim bs = TryCast(bindingSource.DataSource, BindingList(Of Invoices))
        If e.RowIndex >= 0 AndAlso
        dgv.Columns(e.ColumnIndex) Is DataGridView1.Columns("colview") Then
            Dim SelectDgv = GetSELECT()
            Dim Invno = DirectCast(DataGridView1.SelectedRows(0).DataBoundItem, Invoices)
            Dim frm = New Form2(SelectDgv)
            If (TryCast(Application.OpenForms("Form2"), Form2)) IsNot Nothing Then
                'Form is already open
                MessageBox.Show("Form is already open")
            Else
                ' Form is not open
                'MessageBox.Show("Form is not open")
                frm.Show()

            End If
        End If
    End Sub

    Private Sub Btnnew_Click(sender As Object, e As EventArgs) Handles Btnnew.Click
        Dim frm = New Form2()
        If (TryCast(Application.OpenForms("Form2"), Form2)) IsNot Nothing Then
            'Form is already open
            MessageBox.Show("Form is already open")
        Else
            ' Form is not open
            'MessageBox.Show("Form is not open")
`error below code for new ``Operation did not succeed because the program cannot commit or quit a cell value change. ``

            frm.Show()

        End If
    End Sub
End Class

Public Class Invoices
    Public Property INVNO() As String
    Public Property INVDATE() As Date
    Public Property InvoicesDetail() As New List(Of InvoicesDetail)()
End Class
Public Class InvoicesDetail
    <Browsable(False)>
    Public Property INVNO() As String
    Public Property PRODUCTNAME() As String
    Public Property UNIT() As String
    Public Property QTY() As Integer
    Public Class DTOBILLInvoices
        Public Property NAMEINV() As String
        Public Property INVNO() As String
        Public Property INVDATE() As Date
        Public Property TOTPRSINV() As Double
        Public Property PAYMENT() As Double
        Public Property BALANCE() As Double
        Public Property STATUS() As String
    End Class
End Class
Public Module DbContext
    Public Function GetOledbConnectionString() As String
        Return ConfigurationManager.AppSettings("GetOledbConnectionString")
    End Function
    Public Function GetConnection(name As String) As OleDbConnection
        If name = "GetOledbConnectionString" Then
            Return New OleDbConnection(GetOledbConnectionString())
        Else
            Return New OleDbConnection(GetOledbConnectionString())
        End If
    End Function
End Module
Public Class InvoicesService
    Private ReadOnly _conn As OleDbConnection
    Private _connectionString As String = DbContext.GetOledbConnectionString()
    Public Sub New()
        _conn = New OleDbConnection(_connectionString)
    End Sub
    Public Function GetInvoices() As IEnumerable(Of Invoices)
        Dim sql = "SELECT * FROM Invoices"
        Using _conn = New OleDbConnection(GetOledbConnectionString())
            Return _conn.Query(Of Invoices)(sql).ToList()
        End Using
    End Function
    Public Function GetInvoicesdetail(ByVal Invno As String) As IEnumerable(Of InvoicesDetail)
        Dim sql = $"SELECT * FROM InvoicesDetail WHERE Invno = '{Invno}'"
        Using _conn = New OleDbConnection(DbContext.GetOledbConnectionString())
            Return _conn.Query(Of InvoicesDetail)(sql).ToList()
        End Using
    End Function
End Class

code in form2

Imports System.ComponentModel
Imports System.Data.OleDb
Imports System.Reflection
Imports Dapper

Public Class Form2
    Private dictProducts As Dictionary(Of String, Products)
    Dim InvoicesService As New InvoicesService()
    Private BindingSource1 As BindingSource = Nothing
    Private BindingSource2 As BindingSource = Nothing
    Public Sub New(Invno As Invoices)
        Me.New
        DataGridView1.GetType().
 GetProperty("DoubleBuffered",
             BindingFlags.Instance Or BindingFlags.NonPublic).
 SetValue(DataGridView1, True)

        DataGridView1.AllowUserToAddRows = False
        BindingSource2 = New BindingSource With {.DataSource = New BindingList(Of InvoicesDetail)(CType(InvoicesService.GetInvoicesdetail(Invno.INVNO), IList(Of InvoicesDetail)))}
        
        'error below code for view``Operation did not succeed because the program cannot commit or quit a cell value change. ``

        DataGridView1.DataSource = BindingSource2
        For Each column As DataGridViewColumn In DataGridView1.Columns
            column.SortMode = DataGridViewColumnSortMode.NotSortable
        Next column
    End Sub
    Public Sub New()
        ' This call is required by the designer.
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.
        ' To reduce the flickering...
        DataGridView1.GetType().
    GetProperty("DoubleBuffered",
                BindingFlags.Instance Or BindingFlags.NonPublic).
    SetValue(DataGridView1, True)
        updateDataSource()
    End Sub
    Protected Sub updateDataSource()
        dictProducts = ProductsService.GetDistinctProducts().
            ToDictionary(Function(p) p.ToString(), Function(p) p)
        BindingSource1 = New BindingSource With {.DataSource = New BindingList(Of Products)}
        DataGridView1.DataSource = BindingSource1
        DataGridView1.AutoGenerateColumns = False
        DataGridView1.AllowUserToAddRows = False
        DataGridView1.Columns("UNIT").ReadOnly = True
        BindingSource1.AddNew()
    End Sub
    Private Sub DataGridView1_EditingControlShowing(
    sender As Object,
    e As DataGridViewEditingControlShowingEventArgs) Handles _
    DataGridView1.EditingControlShowing
        If TypeOf e.Control Is TextBox Then
            Dim dgv = DirectCast(sender, DataGridView)
            Dim tb = DirectCast(e.Control, TextBox)
            Dim cellRect As Rectangle = DataGridView1.GetCellDisplayRectangle(DataGridView1.CurrentCell.ColumnIndex, DataGridView1.CurrentCell.RowIndex, True)
            If dgv.CurrentCell.ColumnIndex = dgv.Columns("PRODUCTNAME").Index Then
                If tb.AutoCompleteCustomSource.Count = 0 Then
                    tb.AutoCompleteSource = AutoCompleteSource.CustomSource
                    tb.AutoCompleteCustomSource.AddRange(dictProducts.Keys.ToArray())
                End If
                tb.AutoCompleteMode = AutoCompleteMode.Suggest
            Else
                tb.AutoCompleteMode = AutoCompleteMode.None
            End If
        End If
        'End If
    End Sub
    Private Sub DataGridView1_CellValidating(
   sender As Object,
   e As DataGridViewCellValidatingEventArgs) _
   Handles DataGridView1.CellValidating
        Dim dgv = DirectCast(sender, DataGridView)
        If e.ColumnIndex = dgv.Columns("ProductName").Index AndAlso
           e.RowIndex <> dgv.NewRowIndex Then
            Dim key As String
            If dgv.IsCurrentCellInEditMode Then
                Dim p = dictProducts.Values.
                FirstOrDefault(Function(x) x.PRODUCTNAME.
                Equals(e.FormattedValue.
                ToString(), StringComparison.InvariantCultureIgnoreCase))

                If p IsNot Nothing Then
                    key = p.ToString()
                Else
                    key = e.FormattedValue.ToString()
                End If
            Else
                key = dgv(e.ColumnIndex, e.RowIndex).Value?.ToString().Trim()
            End If
            If String.IsNullOrEmpty(key) OrElse
           Not dictProducts.ContainsKey(key) Then
                Dim boundItem = DirectCast(dgv.Rows(e.RowIndex).DataBoundItem, Products)
                boundItem.UNIT = Nothing
                dgv.Rows(e.RowIndex).ErrorText = "Invalid Product!"
                dgv.UpdateCellValue(dgv.Columns("UNIT").Index, e.RowIndex)
                e.Cancel = True
            End If
        End If
    End Sub
    Private Sub DataGridView1_CellEndEdit(
      sender As Object,
      e As DataGridViewCellEventArgs) Handles DataGridView1.CellEndEdit
        Dim dgv = DirectCast(sender, DataGridView)
        Dim src = DirectCast(dgv.DataSource, BindingSource)
        If src.Count = e.RowIndex Then Return
        If e.ColumnIndex = dgv.Columns("PRODUCTNAME").Index AndAlso
        Not String.IsNullOrEmpty(dgv.Rows(e.RowIndex).ErrorText) Then
            Dim key = dgv(e.ColumnIndex, e.RowIndex).Value?.ToString().Trim()
            Dim p As Products = Nothing
            Dim boundItem = DirectCast(dgv.Rows(e.RowIndex).DataBoundItem, Products)

            If String.IsNullOrEmpty(boundItem.UNIT) AndAlso
                dictProducts.TryGetValue(key, p) Then
                boundItem.UNIT = p.UNIT
                dgv.UpdateCellValue(dgv.Columns("UNIT").Index, e.RowIndex)
                dgv.Rows(e.RowIndex).ErrorText = Nothing
            End If
        End If
    End Sub
End Class
Public Class Products
    Public Property PRODUCTNAME() As String
    Public Property UNIT() As String
    Public Property QTY() As Double
    Public Overrides Function ToString() As String
        Return $"{PRODUCTNAME}".Trim()
    End Function
End Class
Public Class ProductsService
    Private ReadOnly _conn As OleDbConnection
    Private _connectionString As String = DbContext.GetOledbConnectionString()
    Public Sub New()
        _conn = New OleDbConnection(_connectionString)
    End Sub
    Friend Shared Function GetDistinctProducts() As IEnumerable(Of Products)
        Dim sql = "SELECT DISTINCT PRODUCTNAME,UNIT
                       FROM Products 
                       ORDER BY PRODUCTNAME"
        Using _conn = New OleDbConnection(GetOledbConnectionString())
            Return _conn.Query(Of Products)(sql)
        End Using
    End Function
End Class

Link database