MSDN Magazine - July 2008 - (Page 68)

Figure 13 Serializing and Deserializing Entities private static T Deserialize (Stream stm, string xmlPayload) { XmlSerializer ser = new XmlSerializer(typeof(T)); T flex = (T)ser.Deserialize(stm); XmlDocument xDom = new XmlDocument(); xDom.LoadXml(xmlPayload); } return flex; Serialize(stm, flex); stm.Position = 0; using (StreamReader reader = new StreamReader(stm)) { return reader.ReadToEnd(); } public static T Deserialize (String xmlPayload) { using (MemoryStream stm = new MemoryStream()) { Encoding encoding = new UTF8Encoding(false); stm.Write(encoding.GetBytes(xmlPayload), 0, encoding. GetByteCount(xmlPayload)); stm.Position = 0; return Deserialize (stm, xmlPayload); } } public static string Serialize (T flex) { using (MemoryStream stm = new MemoryStream()) { } } private static void Serialize (Stream stm, T flex) { XmlSerializer ser = new XmlSerializer(typeof(T)); Encoding encoding = new UTF8Encoding(false); XmlWriterSettings settings = new XmlWriterSettings(); settings.CloseOutput = false; settings.ConformanceLevel = ConformanceLevel.Document; settings.Encoding = encoding; settings.Indent = true; settings.OmitXmlDeclaration = true; } using (XmlWriter writer = XmlWriter.Create(stm, settings)) { ser.Serialize(writer, flex); } method, combined with the Serialize and Deserialize methods, gives you the ability to use strongly typed .NET objects and save them in SSDS. } Label lblFieldType = (Label)fieldItem.FindControl("lblAddFieldType"); entity = entity + String.Format( @" {2} ", lblField.Text.Replace(" ", ""), lblFieldType.Text, tbItem.Text); Using the Custom Listing Schema. As previously mentioned, SSDS entities are flexible, meaning that each entity can have whatever shape you require. The Contoso Classifieds Administration client, for example, gave you the ability to add a schema to a listing category. You can also pull the custom schema out of SSDS and dynamically create an entry form that can be used to add listings to the system. The first step is to create a DataTable with four columns: Field, Value, DataType and Required. This table will hold the fields the administrator has defined for the listing. Next I will query to see whether a customs schema has been defined for the listing: string appDataUri = string.Format(@"http://{0}.{1}{2}", conSSDSAuthName, conSSDSUri, "Categories"); string query = string.Format( @"from e in entities where e[""ListingID""] == ""{0}"" select e", listingCategoryID); UriBuilder newUri = new UriBuilder(appDataUri); newUri.Query = String.Format("q='{0}'", Uri.EscapeDataString(query)); string xmlResults = HTTPHelper.GetHTTPWebRequest(newUri.Uri.ToString(), new System.Net.NetworkCredential(conSSDSUsername, conSSDSPassword)); XmlDocument categoriesDoc = new XmlDocument(); categoriesDoc.LoadXml(xmlResults); XmlNodeList nodeList = categoriesDoc.SelectNodes("//ListingSchema"); Finally, build the URI that points to the container to which you want to POST and issue the POST: string serviceUri = string.Format(@"http://{0}.{1}{2}", postingAuthority, conSSDSUri, postingContainer); HTTPHelper.PostHTTPWebRequest(serviceUri, entity, new System.Net.NetworkCredential( conSSDSUsername, conSSDSPassword)); I can then load the returned XML into the DataTable and bind it to the DataList. In the REST interface, you need to build the XML representation of the entity and issue a HTTP POST to the container into which you want insert the entity. Building the entity is easy—you can simply use a boilerplate entity and loop through each field, adding it as a node in the XML document: foreach (DataListItem fieldItem in dlAddFields.Items) { Label lblField = (Label)fieldItem.FindControl("lblAddField"); TextBox tbItem = (TextBox)fieldItem.FindControl("txtAddValue"); SSDS is easy to develop against. The one point I would like to reiterate is that SSDS is built upon proven SQL Server and Windows Server® technology. While the team has chosen to only reveal a limited set of features in the initial beta release of SSDS, there is a lot more to come. The subset of functionality available now will assist many of the scenarios that customers need to address. Additionally, you can expect to see support for SSDS being added to the other products in the SQL Server suite of products and tools. So, whether you’re a developer using C#, Visual Basic®, Java, Ruby, or even Microsoft Office Access®, SSDS with its support for open protocols is an ideal place for you to store your application’s data. To learn more about it, visit the SSDS site at microsoft.com/sql/ dataservices and sign up for the beta. If there are any additional features you would like to see in the product, please contact me at david.robinson@microsoft.com.  Looking Forward DaviD Robinson is a Senior Program Manager on the SQL Server Data Services team at Microsoft. He spends his time driving new and compelling features into the product. He also enjoys doing presentations at community events and getting feedback from customers on SSDS. 68 msdn magazine SQL Server Data Services http://microsoft.com/sql/dataservices http://microsoft.com/sql/dataservices

Table of Contents Feed for the Digital Edition of MSDN Magazine - July 2008

MSDN Magazine - July 2008 Contents Toolbox CLR Inside Out Flex Your Data Data Points Advanced Basics Office Space Cutting Edge Data Services ADO.NET Data and WPF Transactions WCF P2P Test Run Security Briefs Foundations .NET Matters {End Bracket}

MSDN Magazine - July 2008

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