Using the XPath Property to Filter Nodes

SmartChart allows developers to filter nodes using the XPath or StartNode properties. This example demonstrates how the XPath property can be used with an XPath statement to filter down to a specific employee. The XPath statement looks for any Employee nodes with a child id node equal to 78 (XPath="//Employee[id='78']"). Ancestor nodes of the target node are filtered out completely when using the XPath property. If you're interested in filtering down to a specific node but also allowing the end user to navigate up to an ancestor node use the StartNode property instead.

 

<%@ Page language="c#" MasterPageFile="~/SampleCode/SamplesMasterPage.master" Inherits="SmartWebControls.SampleCode.UsingXPath" CodeFile="UsingXPath.aspx.cs" %>
<%@ Register TagPrefix="swc" Namespace="SmartWebControls" Assembly="SmartWebControls.SmartChart" %>
<asp:Content ID="content" runat="server" ContentPlaceHolderID="cphMain">
    <div id="divTitle">Using the XPath 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 XPath property can be used with an XPath statement to filter down to a specific employee.  The XPath statement
        looks for any Employee nodes with a child id node equal to 78 (XPath="//Employee[id='78']").  Ancestor nodes of the target node are filtered out completely
        when using the XPath property.  If you're interested in filtering down to a specific node but also allowing the end user to navigate
        up to an ancestor node use the StartNode property instead.
    </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="300px" DataNodeName="Employee" DataKeyField="id" DataFields="name,title"
        BoxColor="Gainsboro" BoxGradient="True" ChartDepth="2" 
        font-bold="false" MaxChildrenPerLevelGroup="6" XPath="//Employee[id='78']"
        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 UsingXPath : 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) {
                SmartChart1.DataSource = GetDataSource();
                SmartChart1.DataBind();
            }
        }

        private DataSet GetDataSource() {
            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);
            return ds;

            //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;
        }


    }
}