Using the StartNode Property to Filter Nodes

SmartChart allows developers to filter nodes using the XPath or StartNode properties. This example demonstrates how the StartNode property can be set programmatically to filter down to a specific employee. This example looks for any Employee nodes with a child id node equal to 304. The XML data used in this example is flat (no hierarchy) so a hierarchy is generated by using the DataSet object combined with the XmlDocument object.

 

<%@ Page language="c#" MasterPageFile="~/SampleCode/SamplesMasterPage.master" Inherits="SmartWebControls.SampleCode.UsingStartNode" CodeFile="UsingStartNode.aspx.cs" %>
<%@ Register TagPrefix="swc" Namespace="SmartWebControls" Assembly="SmartWebControls.SmartChart" %>
<asp:Content ID="content" runat="server" ContentPlaceHolderID="cphMain">
    <div id="divTitle">Using the StartNode Property to Filter Nodes</div>
    <div id="divInstructions">
        SmartChart allows developers to filter nodes using the XPath or StartNode properties.  This example demonstrates
        how the StartNode property can be set programmatically to filter down to a specific employee.  This example
        looks for any Employee nodes with a child id node equal to 304.  The XML data used in this example is flat (no hierarchy) 
        so a hierarchy is generated by using the DataSet object combined with the XmlDocument object.
    </div>
    <p></p>
    <asp:Label ID="lblOutput" runat="server" />
    <swc:SmartChartPro id="SmartChart1" title="Org Chart" runat="server" OutputType="Html" AllowDrillDown="True"
        DataTitleFields="name,title" font-size="8" MaxTextLength="30" 
        Width="850px" Height="400px" DataNodeName="Employee" DataKeyField="id" DataFields="name,title"
        BoxColor="Gainsboro" BoxGradient="True" ChartDepth="2" 
        font-bold="false" MaxChildrenPerLevelGroup="6"
        HasParentImagePath="~/SampleCode/SmartChartPro/Images/up.gif" HasParentImageVSpace="6"
        HasChildrenImagePath="~/SampleCode/SmartChartPro/Images/down.gif" HasChildrenImageVSpace="0"
        DrillDownType="SmartChartImage"></swc:SmartChartPro>
        <div style="height:400px;">&nbsp;</div>
</asp:Content>

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Xml;
using System.IO;

namespace SmartWebControls.SampleCode {
    /// <summary>
    /// Summary description for Employees.
    /// </summary>
    public partial class UsingStartNode : System.Web.UI.Page {
    
        protected void Page_Load(object sender, System.EventArgs e) {
            this.SmartChart1.SmartChartClicking += new EventHandler<SmartChartEventArgs>(this.SmartChart1_SmartChartClicking);

            if (!Page.IsPostBack) {
                XmlDocument doc = GetDataSource();
                XmlNode node = doc.SelectSingleNode("//Employee[id='304']");
                SmartChart1.StartNode = node;
                SmartChart1.DataSource = doc;
                SmartChart1.DataBind();
            }
        }

        private XmlDocument GetDataSource() {
            //The XML document used here is in a flat scructure (no hierarchy exists) so load it into DataSet
            //to create relationships
            DataSet ds = new DataSet();
            ds.ReadXml(Server.MapPath("~/SampleCode/SmartChartPro/XML/EmployeesFlatTable.xml"));
            ds.Tables[0].TableName = "Employee";
            DataColumn colParent = ds.Tables[0].Columns["id"];
            DataColumn colChild = ds.Tables[0].Columns["pid"];
            DataRelation relation = new DataRelation("ParentChildRel",colParent,colChild);
            relation.Nested = true;
            ds.Relations.Add(relation);

            //Loading DataSet directly into an XmlDataDocument constructor can cause an error (object reference error)
            //when a large number of relationships are present.  This is a work around
            //to that issue.        
            
            MemoryStream ms = new MemoryStream();
            ds.WriteXml(ms); //Write to memorystream
            ms.Position = 0;
            XmlDocument doc = new XmlDocument();
            doc.Load(ms); //load memorystream into DOM
            ms.Close();
            return doc;
            
        }

        private void SmartChart1_SmartChartClicking(object sender, SmartWebControls.SmartChartEventArgs e) {
            this.lblOutput.Text = "The item you clicked has an ID of: " + e.Item.DataKey;
        }


    }
}