public xlCell(string reference, xlContentType? type, object value, int? sharedId)
 {
     Reference = reference;
     Type = type;
     Value = value;
     SharedId = sharedId;
 }
 //=================================================
 xlFieldAttribute(xlContentType contentType, bool isRequired)
 {
     ContentType = contentType;
     IsRequired = isRequired;
     Captions = new List<string>();
 }
 public xlFieldAttribute(xlContentType contentType, params string[] captions)
     : this(contentType, true, captions)
 {
 }
 public xlFieldAttribute(xlContentType contentType, bool isRequired, string caption)
     : this(contentType, isRequired, new string[] { caption })
 {
 }
 public xlFieldAttribute(xlContentType contentType, bool isRequired, params string[] captions)
     : this(contentType, isRequired)
 {
     captions.ForEach(Captions.Add);
 }