How do you wait for a parallel for to compete all iterations then run a task at the end

 Public Sub Match_Merge(I As Integer)



        Dim lock As New Object

        '  temptable.Reset()

        'if you are comparing 2 tables then both tables need to be sorted
        'order by last name, then first name






        'this will be table 1



        countI = countI + 1
        'this will be table 2

        SyncLock dt.Rows
            For I2 = I3 To dt.Rows.Count - 1

                counti2 = counti2 + 1

                Call match_specifications(I, I2, I3, dt, count, Duplicatestart, nxrecord, matchedmiddlename, newindividual.Middle_name)

                If nxrecord = True Then
                    nxrecord = False
                    GoTo nextrecord
                ElseIf nxI = True Then
                    nxI = False
                    GoTo nxI

                Else

                End If

nxI2:

            Next I2

nextrecord:


            'This will be to collect the duplicate information in second table
            lastduplicaterow = count - 1

            If dt.Rows.Count = 0 Then
                GoTo nxI
            End If

            If newindividual.Individual_ID = Nothing Then
                newindividual.Individual_ID = dt.Rows(Duplicatestart)("Individual_ID")
            End If

            If newindividual.Death_ID = Nothing And dt.Columns.Contains("Death_ID") Then
                If Not IsDBNull(dt.Rows(Duplicatestart)("Death_ID")) Then
                    newindividual.Death_ID = dt.Rows(Duplicatestart)("Death_ID")
                End If
            End If

            If newindividual.Cemetery_ID = Nothing And dt.Columns.Contains("Cemetery_ID") Then
                If Not IsDBNull(dt.Rows(Duplicatestart)("Cemetery_ID")) Then
                    newindividual.Cemetery_ID = dt.Rows(Duplicatestart)("Cemetery_ID")
                End If
            End If

            If newindividual.Burial_ID = Nothing And dt.Columns.Contains("Burial_ID") Then
                If Not IsDBNull(dt.Rows(Duplicatestart)("Burial_ID")) Then
                    newindividual.Burial_ID = dt.Rows(Duplicatestart)("Burial_ID")
                End If
            End If

            'sources and references
            If newindividual.Source_ID = Nothing And dt.Columns.Contains("Source_ID") Then
                If Not IsDBNull(dt.Rows(Duplicatestart)("Source_ID")) Then
                    newindividual.Source_ID = dt.Rows(Duplicatestart)("Source_ID")
                End If
            End If

            If newindividual.Reference_ID = Nothing And dt.Columns.Contains("Reference_ID") Then
                If Not IsDBNull(dt.Rows(Duplicatestart)("Reference_ID")) Then
                    newindividual.Reference_ID = dt.Rows(Duplicatestart)("Reference_ID")
                End If
            End If

            If newindividual.SSN_ID = Nothing And dt.Columns.Contains("SSN_ID") Then
                If Not IsDBNull(dt.Rows(Duplicatestart)("SSN_ID")) Then
                    newindividual.SSN_ID = dt.Rows(Duplicatestart)("SSN_ID")
                End If
            End If

            ' For duprows = Duplicatestart To lastduplicaterow


            For firsttable = 0 To lastduplicaterow

                'collect variables from table 
                Call collect_all_varaibles_from_table(I, I2, firsttable, deathcount, burialcount, cemeterycount, Referencecount, SSNcount, dt, dtcolumns)

                If firsttable = lastduplicaterow Then
                    I = I + lastduplicaterow

                    If updatecount > 0 Then

                        If Not newindividual.Individual_ID = 0 Then

                            If Not newindividual.Individual_ID = Nothing Then
                                UpdateModule.profile(newindividual.Individual_ID, newindividual.First_name, newindividual.Middle_name, newindividual.Last_name, newindividual.Sex, newindividual.Race, newindividual.Place_of_birth, newindividual.State_of_birth, newindividual.County_of_birth, newindividual.Date_of_birth)
                                updatevalue = "yes"
                            End If

                            If Not newindividual.Death_ID = Nothing And deathcount >= 1 Then
                                UpdateModule.death(newindividual.Death_ID, newindividual.Date_of_death, newindividual.Cause_of_death, newindividual.Place_of_death, newindividual.State_of_death, newindividual.County_of_death, newindividual.Age, newindividual.Age_units)
                                updatevalue = "yes"
                            ElseIf newindividual.Death_ID = Nothing And deathcount >= 1 Then
                                Insertmodule.death(newindividual.Individual_ID, newindividual.Date_of_death, newindividual.Cause_of_death, newindividual.Place_of_death, newindividual.State_of_death, newindividual.County_of_death, newindividual.Age, newindividual.Age_units)
                                insertvalue = "Yes"
                            End If

                            If Not newindividual.Cemetery_ID = Nothing And cemeterycount >= 1 And dt.Rows(lastduplicaterow)("Cemetery_name").ToString = newindividual.Cemetery_name Then
                                UpdateModule.Cemetery_reference(newindividual.Cemetery_ID, newindividual.Cemetery_name, newindividual.Cemetery_state, newindividual.Cemetery_county, newindividual.Cemetery_address)
                                updatevalue = "yes"

                            ElseIf newindividual.Cemetery_ID = Nothing And cemeterycount >= 1 Then
                                Insertmodule.Cemetery_reference(newindividual.Cemetery_name, newindividual.Cemetery_state, newindividual.Cemetery_county, newindividual.Cemetery_address)
                                insertvalue = "Yes"

                            End If

                            If Not newindividual.Burial_ID = Nothing And burialcount >= 1 Then
                                UpdateModule.burials(newindividual.Burial_ID, newindividual.Cemetery_Section, newindividual.Cemetery_Row, newindividual.Cemetery_Lot, newindividual.Grave, newindividual.Burial_date)
                                updatevalue = "yes"
                            ElseIf newindividual.Burial_ID = Nothing And burialcount >= 1 Then
                                Insertmodule.burials(newindividual.Individual_ID, newindividual.Cemetery_ID, newindividual.Cemetery_Section, newindividual.Cemetery_Row, newindividual.Cemetery_Lot, newindividual.Grave, newindividual.Burial_date)
                                insertvalue = "Yes"
                            End If

                            If Not newindividual.Source_ID = Nothing Then
                                Insertmodule.Sources(newindividual.Source_ID, newindividual.Source, newindividual.Source_location)
                                'ElseIf newindividual.Source_ID = 0 And Sourcecount >= 1 Then
                                ' Insertmodule.Sources(newindividual.Source_ID, newindividual.Source, newindividual.Source_location)
                                insertvalue = "Yes"
                            End If

                            'If Not newindividual.Reference_ID = 0 And Referencecount >= 1 Then
                            'UpdateModule.References(newindividual.Reference_ID, newindividual.Source_ID, newindividual.Reference_type, newindividual.Reference, newindividual.Individual_ID, newindividual.Source, newindividual.Source_location)
                            'ElseIf newindividual.Reference_ID = 0 And Referencecount >= 1 Then
                            'Insertmodule.References(newindividual.Reference_ID, newindividual.Source_ID, newindividual.Reference_type, newindividual.Reference, newindividual.Individual_ID, newindividual.Source, newindividual.Source_location)
                            'End If

                            If Not newindividual.SSN_ID = 0 And SSNcount >= 1 Then
                                UpdateModule.Social_security("", newindividual.Social_security_number)
                            ElseIf newindividual.SSN_ID = 0 And SSNcount >= 1 Then
                                Insertmodule.SSN(newindividual.SSN_ID, newindividual.Social_security_number, newindividual.Individual_ID)
                                insertvalue = "Yes"
                            End If
                        End If
                    End If
                End If

            Next firsttable

nxI:

            If count < 1 Then

                'non duplicate information
                'before moving to the next record in the temp table copy nonduplicates to another table
                'you can use this table later on to compare to manually match or bulk insert into.
                'get count for all matches

                'remove all duplicates to make a master list
                If dt.Rows.Count > 0 And Not I2 > dt.Rows.Count - 1 Then
                    Call remove_duplicates_from_temptable(I, I2, count, Duplicatestart, dt)
                End If


                removeduptable.ImportRow(temptable.Rows(I))


            Else


                'make a duplicates table to show you which duplicates were found and how many
                duplicaterow = Duplicatetable.NewRow()
                duplicaterow.Item("First_name") = dt.Rows(I2).Item("First_name")
                duplicaterow.Item("Middle_name") = dt.Rows(I2).Item("Middle_name")
                duplicaterow.Item("Last_name") = dt.Rows(I2).Item("Last_name")
                duplicaterow.Item("Duplicatecount") = count

                'add rows to table
                Duplicatetable.Rows.Add(duplicaterow)

            End If



            'always remove all string values before proceeding to next match
            'if this step is not completed you will bring over data from other matches                 
            newindividual.emptyvalues()

            'only for matches
            If count >= 1 Then
                I3 = Duplicatestart + count
            Else
                I3 = I2 + 1
            End If

            count = 0
            deathcount = 0
            Referencecount = 0
            updatecount = 0
            Duplicatestart = Nothing

nxIvalue:
        End SyncLock

movetoend:


        'bring up table that shows duplicates and non duplicates
        'insert into tables if no match is found




        '  MessageBox.Show("table 1: " & countI & "  table 2: " & counti2)

    End Sub

Public Sub ParallelForprocess(ByVal startOfIteration As Integer, ByVal endOfIteration As Integer, ByVal subFunctionName As String)

       startOfIteration = 0
       endOfIteration = temptable.Rows.Count
       Const flags As BindingFlags = BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.Static Or BindingFlags.Instance

       Dim modType As Type = GetType(allmodules)
       ' Find the method with the specified name which accepts a single Integer parameter:
       Dim method As MethodInfo = modType.GetMethod(subFunctionName, flags, Nothing, New Type() {GetType(Integer)}, Nothing)

       If method Is Nothing Then
           Throw New ArgumentException(String.Format("Method '{0}' was not found.", subFunctionName), "subFunctionName")
       End If

       ' Create a delegate of the correct type pointing to the method:
       Dim del As System.Delegate

       del = System.Delegate.CreateDelegate(GetType(Action(Of Integer)), method)

       ' Cast the delegate to the correct type:
       Dim action As Action(Of Integer) = DirectCast(del, Action(Of Integer))

       ' NB: Second parameter to Range is the number of items to return, not the last number to return:
       Dim numbers As IEnumerable(Of Integer) = ParallelEnumerable.Range(startOfIteration, endOfIteration).AsParallel.AsOrdered


       dtcolumns.Add("Cemetery_name")
       dtcolumns.Add("Cemetery_county")
       dtcolumns.Add("Cemetery_state")
       dtcolumns.Add("Cemetery_address")
       dtcolumns.Add("Cemetery_Section")
       dtcolumns.Add("Cemetery_Row")
       dtcolumns.Add("Cemetery_Lot")
       dtcolumns.Add("Grave")
       dtcolumns.Add("Burial_date")

       'connect to
       Dim sqlconn1 As New SqlConnection("my sql statement")
       Dim sqladaptor = New SqlDataAdapter

       sqlconn1.Open()

       sqladaptor.SelectCommand = New SqlCommand("Select Profile.Individual_ID, First_name, Middle_name, Last_name, Sex, Race, Place_of_birth, County_of_birth, State_of_birth, Date_of_birth, death.Death_ID, Place_of_death, State_of_death, County_of_death, Date_of_death, Cause_of_death, Cemetery_reference.Cemetery_ID, Cemetery_name, Cemetery_state, Cemetery_county, Cemetery_address, Cemetery_Section, Cemetery_Row, Cemetery_Lot, Grave, Burial_date from Profile full join Death On profile.Individual_ID = death.individual_ID full join Burial On Profile.Individual_ID = Burial.Individual_ID full join Cemetery_reference On Burial.Cemetery_ID = Cemetery_reference.Cemetery_ID ORDER BY Last_name ASC, First_name ASC, Date_of_birth ASC", sqlconn1)

       sqladaptor.SelectCommand.ExecuteNonQuery()
       sqladaptor.Fill(dt)

       sqlconn1.Close()
       sqlconn1.Dispose()
       sqladaptor.Dispose()

       Dim view As New DataView(temptable)
       view.Sort = "Last_name ASC, First_name ASC, Date_of_birth ASC"
       Dim temptab As DataTable = view.ToTable
       temptable.Clear()
       temptable = temptab

       start_diagnostic("match")
       System.Threading.Tasks.Parallel.ForEach(numbers.AsParallel.AsOrdered, processorcount, action)

       If updatevalue = "yes" Then
           UpdateModule.update_all_tables()
       End If

       If insertvalue = "Yes" Then
           Insertmodule.insert_all()
       End If
       end_diagnostic("match")

       Manualimport.Show()

   End Sub