TreeListNode.Expand() Method

Expands this collapsed node.

Namespace: DevExpress.XtraTreeList.Nodes

Assembly: DevExpress.XtraTreeList.v20.1.dll

Declaration

public void Expand()
Public Sub Expand

Remarks

You can also expand nodes using the TreeListNode.Expanded property.

Example

The following example creates a TreeList at runtime and shows how to perform basic customization tasks:

  • Bind the treelist to a data source
  • Specify the key fields that form a hierarchy
  • Access automatically created columns
  • Set a custom row height
  • Customize column captions (using HTML tags) and cell appearance settings
  • Create unbound columns and create Excel-style format conditions based on these column values
  • Assign an in-place editor (a spin editor) to columns
  • Sort data
  • Calculate total summaries
  • Filter nodes
  • Hide columns and calculate column "best" widths
  • Locate and expand nodes
  • Focus a specific cell
  • Specify DataAnnotation attributes at the data source level (the "p0" display format for the MarketShare field)

Treelist-create-at-runtime

using DevExpress.XtraEditors;
using DevExpress.XtraEditors.Repository;
using DevExpress.XtraTreeList;
using DevExpress.XtraTreeList.Columns;
using DevExpress.XtraTreeList.Nodes;
using DevExpress.XtraTreeList.StyleFormatConditions;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Windows.Forms;

namespace TreeList_example {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e) {
            TreeList treeList1 = new TreeList();
            treeList1.Parent = this;
            treeList1.Dock = DockStyle.Fill; 
            //Specify the fields that arrange underlying data as a hierarchy.
            treeList1.KeyFieldName = "ID";
            treeList1.ParentFieldName = "RegionID";
            //Allow the treelist to create columns bound to the fields the KeyFieldName and ParentFieldName properties specify.
            treeList1.OptionsBehavior.PopulateServiceColumns = true;
            //Specify the data source.
            treeList1.DataSource = SalesDataGenerator.CreateData();
            //The treelist automatically creates columns for the public fields found in the data source. 
            //You do not need to call the TreeList.PopulateColumns method unless the treeList1.OptionsBehavior.AutoPopulateColumns option is disabled.

            //Change the row height.
            treeList1.RowHeight = 23;

            //Access the automatically created columns.
            TreeListColumn colRegion = treeList1.Columns["Region"];
            TreeListColumn colMarchSales = treeList1.Columns["MarchSales"];
            TreeListColumn colSeptemberSales = treeList1.Columns["SeptemberSales"];
            TreeListColumn colMarchSalesPrev = treeList1.Columns["MarchSalesPrev"];
            TreeListColumn colSeptemberSalesPrev = treeList1.Columns["SeptemberSalesPrev"];
            TreeListColumn colMarketShare = treeList1.Columns["MarketShare"];

            //Hide the key columns. An end-user can access them from the Customization Form.
            treeList1.Columns[treeList1.KeyFieldName].Visible = false;
            treeList1.Columns[treeList1.ParentFieldName].Visible = false;

            //Format column headers and cell values.
            colMarchSalesPrev.Caption = "<i>Previous <b>March</b> Sales</i>";
            colSeptemberSalesPrev.Caption = "<i>Previous <b>September</b> Sales</i>";
            treeList1.OptionsView.AllowHtmlDrawHeaders = true;
            colMarchSalesPrev.AppearanceCell.Font = new System.Drawing.Font(colMarchSalesPrev.AppearanceCell.Font, System.Drawing.FontStyle.Italic);
            colSeptemberSalesPrev.AppearanceCell.Font = new System.Drawing.Font(colSeptemberSalesPrev.AppearanceCell.Font, System.Drawing.FontStyle.Italic);

            //Create two hidden unbound columns that calculate their values from expressions.
            TreeListColumn colUnboundMarchChange = treeList1.Columns.AddField("FromPrevMarchChange");
            colUnboundMarchChange.Caption = "Change from prev March";
            colUnboundMarchChange.UnboundType = DevExpress.XtraTreeList.Data.UnboundColumnType.Decimal;
            colUnboundMarchChange.UnboundExpression = "[MarchSales]-[MarchSalesPrev]";
            TreeListColumn colUnboundSeptemberChange = treeList1.Columns.AddField("FromPrevSepChange");
            colUnboundSeptemberChange.Caption = "Change from prev September";
            colUnboundSeptemberChange.UnboundType = DevExpress.XtraTreeList.Data.UnboundColumnType.Decimal;
            colUnboundSeptemberChange.UnboundExpression = "[SeptemberSales]-[SeptemberSalesPrev]";
            colUnboundMarchChange.OptionsColumn.ShowInCustomizationForm = false;
            colUnboundSeptemberChange.OptionsColumn.ShowInCustomizationForm = false;

            //Make the Region column read-only.
            colRegion.OptionsColumn.ReadOnly = true;

            //Sort data against the Region column
            colRegion.SortIndex = 0;

            //Apply a filter.
            treeList1.ActiveFilterString = "[MarchSales] > 10000";

            //Calculate two total summaries against root nodes.
            colMarchSales.SummaryFooter = DevExpress.XtraTreeList.SummaryItemType.Sum;
            colMarchSales.SummaryFooterStrFormat = "Total={0:c0}";
            colMarchSales.AllNodesSummary = false;
            colSeptemberSales.SummaryFooter = DevExpress.XtraTreeList.SummaryItemType.Sum;
            colSeptemberSales.SummaryFooterStrFormat = "Total={0:c0}";
            colSeptemberSales.AllNodesSummary = false;
            treeList1.OptionsView.ShowSummaryFooter = true;

            //Use a 'SpinEdit' in-place editor for the *Sales columns.
            RepositoryItemSpinEdit riSpinEdit = new RepositoryItemSpinEdit();
            riSpinEdit.DisplayFormat.FormatType = DevExpress.Utils.FormatType.Numeric;
            riSpinEdit.DisplayFormat.FormatString = "c0";
            treeList1.RepositoryItems.Add(riSpinEdit);
            colMarchSales.ColumnEdit = riSpinEdit;
            colMarchSalesPrev.ColumnEdit = riSpinEdit;
            colSeptemberSales.ColumnEdit = riSpinEdit;
            colSeptemberSalesPrev.ColumnEdit = riSpinEdit;

            //Apply Excel-style formatting: display predefined 'Up Arrow' and 'Down Arrow' icons based on the unbound column values.
            TreeListFormatRule rule1 = new TreeListFormatRule();
            rule1.Rule = createThreeTrianglesIconSetRule();
            rule1.Column = colUnboundMarchChange;
            rule1.ColumnApplyTo = colMarchSales;
            TreeListFormatRule rule2 = new TreeListFormatRule();
            rule2.Rule = createThreeTrianglesIconSetRule();
            rule2.Column = colUnboundSeptemberChange;
            rule2.ColumnApplyTo = colSeptemberSales;
            treeList1.FormatRules.Add(rule1);
            treeList1.FormatRules.Add(rule2);

            //Do not stretch columns to the treelist width.
            treeList1.OptionsView.AutoWidth = false;

            //Locate a node by a value it contains.
            TreeListNode node1 = treeList1.FindNodeByFieldValue("Region", "North America");
            //Focus and expand this node.
            treeList1.FocusedNode = node1;
            node1.Expanded = true;

            //Locate a node by its key field value and expand it.
            TreeListNode node2 = treeList1.FindNodeByKeyID(32);//Node 'Asia'
            node2.Expand();

            //Calculate the optimal column widths after the treelist is shown.
            this.BeginInvoke(new MethodInvoker(delegate {
                treeList1.BestFitColumns();
            }));
        }

        FormatConditionRuleIconSet createThreeTrianglesIconSetRule() {
            FormatConditionRuleIconSet ruleIconSet = new FormatConditionRuleIconSet();
            FormatConditionIconSet iconSet = ruleIconSet.IconSet = new FormatConditionIconSet();
            FormatConditionIconSetIcon icon1 = new FormatConditionIconSetIcon();
            FormatConditionIconSetIcon icon2 = new FormatConditionIconSetIcon();
            FormatConditionIconSetIcon icon3 = new FormatConditionIconSetIcon();
            //Choose predefined icons. 
            icon1.PredefinedName = "Triangles3_3.png";
            icon2.PredefinedName = "Triangles3_2.png";
            icon3.PredefinedName = "Triangles3_1.png";
            //Specify the type of threshold values. 
            iconSet.ValueType = FormatConditionValueType.Number;
            //Define ranges to which icons are applied by setting threshold values. 
            icon1.Value = Decimal.MinValue;
            icon1.ValueComparison = FormatConditionComparisonType.GreaterOrEqual;
            icon2.Value = 0;
            icon2.ValueComparison = FormatConditionComparisonType.GreaterOrEqual;
            icon3.Value = 0;
            icon3.ValueComparison = FormatConditionComparisonType.Greater;
            //Add icons to the icon set. 
            iconSet.Icons.Add(icon1);
            iconSet.Icons.Add(icon2);
            iconSet.Icons.Add(icon3);
            return ruleIconSet;
        }
    }

    public class SalesData {
        static int UniqueID = 37;
        public SalesData() {
            ID = UniqueID++;
        }
        public SalesData(int id, int regionId, string region, decimal marchSales, decimal septemberSales, decimal marchSalesPrev, decimal septermberSalesPrev, double marketShare) {
            ID = id;
            RegionID = regionId;
            Region = region;
            MarchSales = marchSales;
            SeptemberSales = septemberSales;
            MarchSalesPrev = marchSalesPrev;
            SeptemberSalesPrev = septermberSalesPrev;
            MarketShare = marketShare;
        }
        public int ID { get; set; }
        public int RegionID { get; set; }
        public string Region { get; set; }
        public decimal MarchSales { get; set; }
        public decimal SeptemberSales { get; set; }
        public decimal MarchSalesPrev { get; set; }
        public decimal SeptemberSalesPrev { get; set; }

        [DisplayFormat(DataFormatString = "p0")]
        public double MarketShare { get; set; }
    }

    public class SalesDataGenerator {
        public static List<SalesData> CreateData() {
            List<SalesData> sales = new List<SalesData>();
            sales.Add(new SalesData(0, -1, "Western Europe", 30540, 33000, 32220, 35500, .70));
            sales.Add(new SalesData(1, 0, "Austria", 22000, 28000, 26120, 28500, .92));
            sales.Add(new SalesData(2, 0, "France", 23020, 27000, 20120, 29200, .51));
            sales.Add(new SalesData(3, 0, "Germany", 30540, 33000, 32220, 35500, .93));
            sales.Add(new SalesData(4, 0, "Spain", 12900, 10300, 14300, 9900, .82));
            sales.Add(new SalesData(5, 0, "Switzerland", 9323, 10730, 7244, 9400, .14));
            sales.Add(new SalesData(6, 0, "United Kingdom", 14580, 13967, 15200, 16900, .91));

            sales.Add(new SalesData(17, -1, "Eastern Europe", 22500, 24580, 21225, 22698, .62));
            sales.Add(new SalesData(18, 17, "Belarus", 7315, 18800, 8240, 17480, .34));
            sales.Add(new SalesData(19, 17, "Bulgaria", 6300, 2821, 5200, 10880, .8));
            sales.Add(new SalesData(20, 17, "Croatia", 4200, 3890, 3880, 4430, .29));
            sales.Add(new SalesData(21, 17, "Russia", 22500, 24580, 21225, 22698, .85));

            sales.Add(new SalesData(26, -1, "North America", 31400, 32800, 30300, 31940, .84));
            sales.Add(new SalesData(27, 26, "USA", 31400, 32800, 30300, 31940, .87));
            sales.Add(new SalesData(28, 26, "Canada", 25390, 27000, 5200, 29880, .64));

            sales.Add(new SalesData(29, -1, "South America", 16380, 17590, 15400, 16680, .32));
            sales.Add(new SalesData(30, 29, "Argentina", 16380, 17590, 15400, 16680, .88));
            sales.Add(new SalesData(31, 29, "Brazil", 4560, 9480, 3900, 6100, .10));

            sales.Add(new SalesData(32, -1, "Asia", 20388, 22547, 22500, 25756, .52));
            sales.Add(new SalesData(34, 32, "India", 4642, 5320, 4200, 6470, .44));
            sales.Add(new SalesData(35, 32, "Japan", 9457, 12859, 8300, 8733, .70));
            sales.Add(new SalesData(36, 32, "China", 20388, 22547, 22500, 25756, .82));
            return sales;
        }
    }

}
See Also