productcatalog4439.cs

和数据库连接,能实现数据列的编辑,删除等功能.

using System;
using System.IO;
using System.Xml;
using System.Xml.XPath;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;


namespace CSProduct_Catalog4439
{
    public partial class ProductCatalog4439 : Form
    {
        private XmlDataDocument xml_data;
        private DataSet relational_data;

        public ProductCatalog4439()
        {
            InitializeComponent();
        }

        private void DataGrid1_CurrentCellChanged(object sender, EventArgs e)
        {
            Xml_TxtBx.Text = xml_data.InnerXml.ToString();
        }

        private void Button1_Click(object sender, EventArgs e)
        {
            if (Button1.Text.Equals("Query"))
            {
                if (RadioButton1.Checked)
                {
                    // Create an XPathNavigator object
                    XPathNavigator navigator;
                    navigator = xml_data.CreateNavigator();

                    // Create and compile an XPathExpression
                    XPathExpression expr;
                    try
                    {
                        expr = navigator.Compile(
                            "descendant::product[id=" +
                            Id_TxtBx.Text + "]");
                        // Call the Select method on the XPathNavigator
                        // object and store the reference to the
                        // XPathNodeIterator object returned by the 
                        // Select method
                        XPathNodeIterator iterator;
                        iterator = navigator.Select(expr);

                        // Navigate to get the value of id, name, 
                        // and price 
                        iterator.MoveNext();
                        XPathNavigator nav2 = iterator.Current.Clone();
                        nav2.MoveToFirstChild();
                        Id_TxtBx.Text = nav2.Value;
                        nav2.MoveToNext();
                        Name_TxtBx.Text = nav2.Value;
                        nav2.MoveToNext();
                        Price_TxtBx.Text = nav2.Value;
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show("Enter a valid product id");
                    }
                }

                else if (RadioButton2.Checked)
                {
                    // Create an XPathNavigator object
                    XPathNavigator navigator;
                    navigator = xml_data.CreateNavigator();

                    // Create and compile an XPathExpression
                    XPathExpression expr;
                    try
                    {
                        expr = navigator.Compile(
                            "descendant::product[name='" +
                            Name_TxtBx.Text + "']");
                        // Call the Select method on the XPathNavigator
                        // object and store the reference to the
                        // XPathNodeIterator object returned by the 
                        // Select method
                        XPathNodeIterator iterator;
                        iterator = navigator.Select(expr);

                        // Navigate to get the value of id, name, 
                        // and price 
                        iterator.MoveNext();
                        XPathNavigator nav2 = iterator.Current.Clone();
                        nav2.MoveToFirstChild();
                        Id_TxtBx.Text = nav2.Value;
                        nav2.MoveToNext();
                        Name_TxtBx.Text = nav2.Value;
                        nav2.MoveToNext();
                        Price_TxtBx.Text = nav2.Value;
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show("Enter a valid product name, " +
                            "which is case sensitive.");
                    }
                }
                Button1.Text = "Clear";
                GroupBox1.Text = "Clear Query";
            }
            else
            {
                Id_TxtBx.Text = "";
                Name_TxtBx.Text = "";
                Price_TxtBx.Text = "";
                Button1.Text = "Query";
                GroupBox1.Text = "Enter Query";
            }

        }

        private void RadioButton2_CheckedChanged(object sender, EventArgs e)
        {
            Id_TxtBx.ReadOnly = true;
            Name_TxtBx.ReadOnly = false;
            Name_TxtBx.Focus();     

        }

        private void RadioButton1_CheckedChanged(object sender, EventArgs e)
        {
            Id_TxtBx.ReadOnly = false;
            Name_TxtBx.ReadOnly = true;
            Id_TxtBx.Focus();
        }

        private void Button2_Click(object sender, EventArgs e)
        {
            // Read the XML data from the Xml_TxtBx into the DataSet
            // object
            XmlTextReader xml_reader = new XmlTextReader(new
                   StringReader(Xml_TxtBx.Text));
            relational_data = new DataSet();
            relational_data.ReadXml(xml_reader);

            // Create a new XmlDataDocument object
            xml_data = new XmlDataDocument(relational_data);

            // Save the changes in the products.xml file
            relational_data.WriteXml(@"..\..\products4439.xml");

            // Show the data in the DataGrid
            DataGrid1.DataSource = xml_data.DataSet.Tables[0];

        }

        private void ProductCatalog_Load(object sender, EventArgs e)
        {
            // Load products data into the DataSet object
            relational_data = new DataSet();
            relational_data.ReadXml(@"..\..\products4439.xml");

            // Display the data in DataGrid1 
            DataGrid1.DataSource = relational_data.Tables[0];

            // Synchronize the DataSet with the XmlDataDocument object.
            // Any change made in the DataSet object is automatically 
            // made in the XmlDataDocument object.
            xml_data = new XmlDataDocument(relational_data);

            // Show the XML view in the Xml_TxtBx textbox
            Xml_TxtBx.Text = xml_data.InnerXml.ToString();

        }

    }
}