public class XNField : XField

Public Class XNField
	Inherits XField

Imports System
Imports System.Collections
Imports System.Text  '    for StringBuilder
Imports Biolomics.BioCallback
Imports Biolomics.SharedClasses

Public Class MyNewClass

    ' This function is called when running this script
    Shared Sub Main()

        '    Create an instance of class MyNewClass and call its functions
        Dim c As New MyNewClass
        c.ChangeField()
    End Sub

    '    Write sub functions here
    Public Sub ChangeField()
        '    get the current connection
        Dim SqlCo As XConnection = Run.GetCurrentConnection()
        If SqlCo Is Nothing Then
            Return
        End If

        '    get a table from its User name
        Dim TableDef As XTableDef = SqlCo.GetTableDefByUserNameEng("Your_Table_Name")
        If TableDef Is Nothing Then   '    may happen if that table doesn't exist
            Return
        End If
        '    load a Field from that table
        Dim FieldDefMap As New XFieldDefMap
        Dim FieldDef As XFieldDef = SqlCo.GetFieldByDBName("Your_N_Field_name", TableDef.Key)
        If FieldDef Is Nothing Then   '    that field doesn't exist
            Return
        End If
        FieldDefMap.Add(FieldDef)

        '    load about 10 records
        Dim Where As XWhere = XWhere.LTE(StaticFields.id, 11)
        Dim RecordMap As XRecordMap = Run.LoadRecords(TableDef.Key, FieldDefMap, Where)

        For Each Record As XRecord In RecordMap
            Dim Field As XNField = TryCast(Record.Fields(FieldDef.Key), XNField)
            If Field Is Nothing Then   '    this field doesn't exist or is not a N-Field
                Continue For
            End If
            '    build the reverse-complement string (not the fastest method, but easy to understand)
            Dim strB As New StringBuilder(Field.Value.Length) '    the destination string    
            For Each c As Char In Field.Value
                Select Case c
                    Case "a"c
                        strB.Append("t"c)
                    Case "c"c
                        strB.Append("g"c)
                    Case "g"c
                        strB.Append("c"c)
                    Case "t"c
                        strB.Append("a"c)
                    Case "A"c
                        strB.Append("T"c)
                    Case "C"c
                        strB.Append("G"c)
                    Case "G"c
                        strB.Append("C"c)
                    Case "T"c
                        strB.Append("A"c)
                    Case Else
                        strB.Append(c) '    no change
                End Select
            Next
            '    copy the result into the field value
            Field.Value = strB.ToString

            Record.Save(False)
        Next

    End Sub

End Class