internal void AddField(string fieldName, int elementIndex)
{
var map = new MapField(fieldName, elementIndex);
MapFields.Add(map);
}
internal void AddField(string fieldName, int start, int length, string startWith = "", string columnName = "")
{
var map = new MapField(fieldName, start, length, startWith, columnName);
this.MapFields.Add(map);
}