IfcDoc.CtlParameters.dataGridViewConceptRules_CellValidated C# (CSharp) Method

        private void dataGridViewConceptRules_CellValidated(object sender, DataGridViewCellEventArgs e)
        {
            if (this.m_editcon)
                return;

            // format parameters

            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < this.dataGridViewConceptRules.Columns.Count - 1; i++)
            {
                object val = this.dataGridViewConceptRules[i, e.RowIndex].Value;
                if (val != null)
                {
                    DataGridViewColumn col = this.dataGridViewConceptRules.Columns[i];
                    if (col.Tag is DocModelRule)
                    {
                        DocModelRule rule = (DocModelRule)col.Tag;

                        sb.Append(rule.Identification);
                        sb.Append("=");
                        sb.Append(val as string);
                        sb.Append(";");
                    }
                    else
                    {
                        this.ToString(); // description???
                    }
                }
            }

            List<DocTemplateItem> listItems = null;
            if(this.m_conceptleaf != null)
            {
                listItems = this.m_conceptleaf.Items;
            }
            else
            {
                listItems = this.m_conceptroot.ApplicableItems;
            }

            if (listItems.Count > e.RowIndex)
            {
                DocTemplateItem docItem = listItems[e.RowIndex];
                docItem.RuleParameters = sb.ToString();
                object val = this.dataGridViewConceptRules[this.dataGridViewConceptRules.Columns.Count - 1, e.RowIndex].Value;
                docItem.Documentation = val as string;
            }
        }