private void SetDataGridTemplate()
        {
            this.datagrid.Columns.Clear();
            this.datagrid.GroupDescriptors.Clear();
            this.datagrid.Templates.Clear();
            this.datagrid.Relations.Clear();

            this.datagrid.Columns.AddRange(
                new GridViewDecimalColumn("idsub"),
                new GridViewTextBoxColumn("name"),
                    new GridViewTextBoxColumn("unit"),
                new GridViewDecimalColumn("price"));

            var child = new GridViewTemplate();
            child.Columns.AddRange(
                new GridViewDecimalColumn("idsub"),
                new GridViewTextBoxColumn("itemname"),
                new GridViewDecimalColumn("qty"),
                new GridViewTextBoxColumn("satuan"),
                new GridViewDecimalColumn("price"),
                new GridViewDecimalColumn("total"),
                new GridViewDecimalColumn("idcategory"),
                new GridViewTextBoxColumn("category")
                );
            this.datagrid.Templates.Add(child);
            var grupKategori = new GroupDescriptor
            {
                Format = "{0}{1}"
            };
            grupKategori.GroupNames.Add("idcategory", ListSortDirection.Ascending);
            grupKategori.GroupNames.Add("category", ListSortDirection.Ascending);
            this.datagrid.Templates[0].GroupDescriptors.Add(grupKategori);

            var item1 = new GridViewSummaryItem { Name = "price", Aggregate = GridAggregateFunction.Sum, FormatString = "" };
            var item2 = new GridViewSummaryItem { Name = "total", Aggregate = GridAggregateFunction.Sum, FormatString = "{0:0}" };
            var rowSummary = new GridViewSummaryRowItem(new[] { item1, item2 });
            this.datagrid.Templates[0].SummaryRowsBottom.Add(rowSummary);

            this.datagrid.Templates[0].ShowParentGroupSummaries = true;
            this.datagrid.Templates[0].ShowTotals = true;

            var relation = new GridViewRelation();
            relation.ParentTemplate = this.datagrid.MasterTemplate;
            relation.ChildTemplate = this.datagrid.Templates[0];
            relation.ParentColumnNames.Add("idsub");
            relation.ChildColumnNames.Add("idsub");
            this.datagrid.Relations.Add(relation);
        }

        private void buttonLoad_Click(object sender, EventArgs e)
        {
            this.SetDataGridTemplate();
            this.datagrid.DataSource = GetParentSource();
            this.datagrid.Templates[0].DataSource = GetChildSource();
        }

        private void datagrid_GroupSummaryEvaluate(object sender, GroupSummaryEvaluationEventArgs e)
        {
            switch (e.SummaryItem.Name)
            {
                case "idcategory":
                    string[] arr = e.Value.ToString().Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries);
                    string strvalue = e.Value.ToString();
                    if (strvalue.Contains(","))
                    {
                        arr = e.Value.ToString().Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
                        if (arr.Length > 1)
                        {
                            e.FormatString = arr[1];
                        }
                    }
                    break;
                case "total":
                    switch (e.Parent)
                    {
                        case GridViewGroupRowInfo _:
                            e.FormatString = "{0:0}";
                            break;
                        case GridViewHierarchyRowInfo _:
                            e.FormatString = "{0:0}";
                            break;
                    }
                    break;
                case "price":
                    if (e.Parent is GridViewGroupRowInfo GroupRow)
                    {
                        e.FormatString = $"SubTotal {GroupRow.HeaderText}";
                    }
                    else if (e.Parent == this.datagrid.MasterView.ViewTemplate)
                    {
                        e.FormatString = "Total ";
                    }
                    else if (e.Parent is GridViewHierarchyRowInfo h)
                    {
                        e.FormatString = "Total ";
                    }
                    break;
            }
        }