public ISqlSearch Clone()
        {
            var clone = new UnitSearch();

            clone.CopyFrom(this);
            return(clone);
        }
        public void CopyFrom(UnitSearch source)
        {
            this.Property = source.Property;
            this.Mode     = source.Mode;

            this.Reference = source.Reference;

            this._fieldReferenceLabel = null;
        }