Compare two excel files using ClosedXML

[luckydead]

Hello,
Can someone help me how i can compare two excel files.

What i want to do is to take from File1.xlsx file specific columns to read
Then to check does in File2 in specific column exists this records if not display in datagridview the error

here is my code

Using workBook As XLWorkbook = New XLWorkbook(TxtPathLocation.Text + "\ConnectorListMST.xlsx")
                Using workBook2 As XLWorkbook = New XLWorkbook(TxtPathLocation.Text + "\Production modules.xlsx")
                    Dim workSheet As IXLWorksheet = workBook.Worksheet(1)
                    Dim workSheet2 As IXLWorksheet = workBook2.Worksheet(1)
                    Dim dt As DataTable = New DataTable()
                    Dim dt2 As DataTable = New DataTable()
                    Dim firstRow As Boolean = True
                    For Each row As IXLRow In workSheet.Rows()
                        For Each row2 As IXLRow In workSheet2.Rows()
                            If firstRow Then
                                For Each cell As IXLCell In row.Cells()
                                    dt.Columns.Add(cell.Value.ToString())
                                Next
                                For Each cell2 As IXLCell In row2.Cells()
                                    dt2.Columns.Add(cell2.Value.ToString())
                                Next
                                firstRow = False
                            Else
                                Dim cellA As IXLCell = row.Cell(1) 'Yazaki Number
                                Dim cellB As IXLCell = row.Cell(2) 'TAB Folder
                                Dim cellC As IXLCell = row.Cell(3) 'SYM File
                                Dim cellE As IXLCell = row2.Cell(3) 'Material
                                Dim cellD As IXLCell = row2.Cell(4) 'Yazaki Number
                                Dim cellF As IXLCell = row2.Cell(6) 'Note
                                Dim isLowerLetter As Boolean = False
                                Dim isLowerLetter2 As Boolean = False

                                If Not String.IsNullOrEmpty(cellA.Value) Then
                                    If String.IsNullOrEmpty(cellB.Value) Or String.IsNullOrEmpty(cellC.Value) Then
                                        isLowerLetter = True
                                    End If
                                End If

                                If String.IsNullOrEmpty(cellA.Value) Then
                                    If Not String.IsNullOrEmpty(cellB.Value) Or Not String.IsNullOrEmpty(cellC.Value) Then
                                        isLowerLetter = True
                                    End If
                                End If

                                If String.IsNullOrEmpty(cellA.Value) And String.IsNullOrEmpty(cellB.Value) And String.IsNullOrEmpty(cellC.Value) Then
                                    isLowerLetter = True
                                End If

                                If cellF.Value.ToString.Contains("Connector") Or cellF.Value.ToString.Contains("connector") Then
                                    If Not String.IsNullOrEmpty(cellE.Value) And Not String.IsNullOrEmpty(cellD.Value) Then
                                        If cellA.Value.ToString() <> cellD.Value.ToString() Then
                                            isLowerLetter2 = True
                                        End If
                                    End If
                                End If


                                If isLowerLetter Then
                                    If String.IsNullOrEmpty(cellA.Value) Then
                                        DataGridView2.Rows.Add("", "ConnectorListMST", "", cellB.Value.ToString() & "/" & cellC.Value.ToString(), "Found issue with missing connector information")
                                    Else
                                        DataGridView2.Rows.Add("", "ConnectorListMST", "", cellA.Value.ToString(), "Found issue with missing connector information")
                                    End If
                                End If
                                If isLowerLetter2 Then
                                    DataGridView2.Rows.Add("", "ConnectorListMST", "Production Modules", cellE.Value.ToString(), "Found Mismatch connector information")
                                End If
                            End If
                        Next
                    Next

https://ibb.co/QdbWLnD
https://ibb.co/ZY9Ny0D

So img1 is File1.xlsx and i want to read from column "D" the numbers and that answers to column "F" contains letter "connector".
Then to check this numbers do they exists in File2.xlsx in column A
Forgot to mention that in File1.xlsx it can contain same connectors with same numbers multiple times, to not use duplicates results in the end.
Example:
C88 6743434553
C88 6743434553
C88 6743434553
C88 6743434553
To read it only 1 time as result in the end if this number 6743434553 not exists in File2 column "A"
Thats all