Create a program to view orders:

• Create a database with the tables ‘Order’, ‘Product’, ‘Amount’;
• Provide scripts to create the database and populate it with test data;
• Access database using the NHibernate 2;
• Get data on the client using the WCF service;
• Display data in the Infragistics UltraGrid;
• Display order details in a separate grid;
• User should be able to select some items in the details grid and display them as an xml document in the text field;
• User should be able to edit the xml document and send it to the server where it is being validated;
• If validation is passed the service returns the positions as a list and client displays it in a separate window.

I have created a simple ADO.NET project to populate the database with the test data which can be found in the downloadable source code. Sql Server allows to publish the database schema as a script but to publish the database along with the data some helper tool should be used, for example, Microsoft SQL Server Database Publishing Wizard. It allows to publish the database schema and data, schema only or data only.

NHibernate project can be created using CodeSmith Tools. Next add the method to return orders for the specified period:

        public IList<MyOrder> GetOrders(DateTime from, DateTime to)
        {
            IList<MyOrder> orders;
            using (ISession session = NHibernateHelper.OpenSession())
            {
                orders = session.CreateQuery("from Order where date between :from and :to")
                    .SetParameter("from", from)
                    .SetParameter("to", to.AddDays(1))
                    .List<MyOrder>();

                foreach (var order in orders)
                {
                    NHibernateUtil.Initialize(order.Amounts);
                    foreach (var amount in order.Amounts)
                    {
                        NHibernateUtil.Initialize(amount.Product);
                    }
                }
            }
            return orders;
        }

“from Order where date between :from and :to” is the Hibernate Query Language statement, “:from” and “:to” are parameters, their values are set in the SetParameter() method. The call to List<MyOrder>() method forces the query to evaluate immediately. NHibernateUtil.Initialize() method loads linked data.

Next create the WCF service and add a method to get orders:

        public IList<Order> GetOrders(DateTime from, DateTime to)
        {
            OrderRepository repository = new OrderRepository();
            return repository.GetOrders(from, to);
        }

On the client add the service reference, call the service and display the results:

        private void showOrdersButton_Click(object sender, EventArgs e)
        {
            Order[] orders;
            try
            {
                orders = serviceClient.GetOrders(dateFrom.Value.Date, dateTo.Value.Date);
            }
            catch (Exception)
            {
                MessageBox.Show("Service Error.");
                return;
            }

            ordersGrid.DataSource = orders;
        }

UltraGrid customization is performed in the InitializeLayout event handler:

        private void ordersGrid_InitializeLayout(object sender, Infragistics.Win.UltraWinGrid.InitializeLayoutEventArgs e)
        {
            //Set columns' order and visibility.
            ordersGrid.DisplayLayout.Bands[0].Columns[0].Hidden = true;
            ordersGrid.DisplayLayout.Bands[0].Columns[3].Hidden = true;
            ordersGrid.DisplayLayout.Bands[0].Columns[4].Header.VisiblePosition = 0;
            ordersGrid.DisplayLayout.Bands[0].Columns[2].Header.VisiblePosition = 1;

            //Select entire row on click and make all columns to be the same size.
            ordersGrid.DisplayLayout.Override.CellClickAction = CellClickAction.RowSelect;
            ordersGrid.DisplayLayout.AutoFitStyle = AutoFitStyle.ResizeAllColumns;
        }

CreateXMLStringFromSelectedRows() creates xml document from the selected items in the details grid:

        private static string CreateXMLStringFromSelectedRows(SelectedRowsCollection selectedRows)
        {
            TextWriter stringWriter = new StringWriter();
            XmlTextWriter xmlWriter = new XmlTextWriter(stringWriter);
            xmlWriter.Formatting = Formatting.Indented;

            xmlWriter.WriteStartDocument();
            xmlWriter.WriteStartElement("Positions");

            foreach (var row in selectedRows)
            {
                xmlWriter.WriteStartElement("Position");

                xmlWriter.WriteStartElement("Product");
                xmlWriter.WriteString(((OrderDetails)row.ListObject).Product);
                xmlWriter.WriteEndElement();

                xmlWriter.WriteStartElement("Amount");
                xmlWriter.WriteString(((OrderDetails)row.ListObject).Amount.ToString());
                xmlWriter.WriteEndElement();

                xmlWriter.WriteEndElement();
            }

            xmlWriter.WriteEndElement();

            xmlWriter.Flush();
            xmlWriter.Close();
            stringWriter.Flush();

            return stringWriter.ToString();
        }

This approach has some issues for encoding since .NET uses UTF-16 encoding for strings.  You can follow this post and comments for more information.

Now add a method to the service to parse the xml string and return the list of items:

        private List<string> validationErrors = new List<string>();

        public IList<string> GetOrderDetailsFromXML(string xmlString)
        {
            IList<string> result = new List<string>();
            string errorMessage = String.Empty;
            validationErrors = new List<string>();
            XmlDocument doc = new XmlDocument();
            XmlReader docReader = CreateXmlReader(ref xmlString);
            ...
        }

CreateXmlReader() method creates an object of the XmlReaderSettings class, specifies the xsd schema to validate against and registers ValidationEventHandler:

        private XmlReader CreateXmlReader(ref string xmlString)
        {
            //If encoding of the xml document is specified "encoding="utf-16"",
            //replace it with "encoding="utf-8"".
            xmlString = Regex.Replace(xmlString, "encoding=.utf-16.", "encoding=\"utf-8\"");

            XmlReaderSettings settings = new XmlReaderSettings();
            settings.ValidationType = ValidationType.Schema;

            //Load schema in shemas collection.
            TextReader stringReader = new StringReader(Properties.Resources.schema);
            XmlReader schemaDocument = new XmlTextReader(stringReader);
            settings.Schemas.Add("", schemaDocument);

            settings.ValidationEventHandler += new System.Xml.Schema.ValidationEventHandler(OnValidationError);
            XmlReader docReader = XmlReader.Create(new StringReader(xmlString), settings);

            return docReader;
        }

When validation error occurs get the message to show it to the user later:

        void OnValidationError(object sender, System.Xml.Schema.ValidationEventArgs e)
        {
            validationErrors.Add(e.Message);
        }
 

When xml document has been created and validated get the list of items:

           public IList<string> GetOrderDetailsFromXML(string xmlString)
           {
             ...
            foreach (XmlNode position in doc.DocumentElement.ChildNodes)
            {
                StringBuilder positionInfo = new StringBuilder();

                // Read 'Product' and 'Amount' nodes.
                foreach (XmlNode item in position.ChildNodes)
                {
                    positionInfo.Append(item.InnerText);
                    positionInfo.Append('\t');
                }

                result.Add(positionInfo.ToString());
            }

            return result;
           }
 

That’s it.

Download source code.