MSDN Magazine - August 2008 - (Page 11)

ScOtt Mitchell Toolbox Serializing Objects, Scott Allen’s Blog, Site Performance, And More Serialize and Deserialize FixedLength and Delimited Files I was recently working on a project where we needed to import several thousand records stored in a comma-delimited file into our Microsoft .NET Framework application. Not only did our application need to import this data, but it also needed the ability to export data in the same format for use by external programs that still rely on the data in a delimited format. If you’ve ever used the .NET Framework built-in XML or binary serialization capabilities, you know how easy it is to save an object’s state to disk as an XML or binary file, as well as how easy it is to reload the object from disk back into memory. In a nutshell, you decorate a class with attributes, indicating how the class’s properties are to be serialized. Once the class has been decorated, serializing or deserializing an object requires just one line of code. While the .NET Framework includes serialization formatter classes for serializing objects to XML and binary formats, it does not include formatters for working with comma-delimited files. The good news is that serializing objects to fixed-length and delimited text files is as easy as XML and binary serialization thanks to FileHelpers version 2.0 by Marcos Meli. To use FileHelpers to serialize an array of class instances to a fixed-length or delimited text file, start by decorating the class’s properties with the applicable attributes. When serializing to fixed-length files, there is an attribute to indicate the length of each field; when serializing to delimited files, there’s an attribute to indicate the delimiter. There are also attributes that you can use to indicate the data type and format of the data, whether white space should be ® Serialize and Deserialize Fixed-Length and Delimited Files trimmed, and whether the field is optional. An appropriately decorated class is referred to as a record class. (In addition to using attributes to specify serialization specifics, FileHelpers also includes an API for programmatically defining the serialization and deserialization rules at run time.) As you may know, creating the record class can be a tedious process. To help streamline the process and reduce the chance of a syntax error or typo, FileHelpers ships with a Record Class Wizard program. The wizard is a standalone GUI application that prompts for the precise fields in the fixed-length or delimited file and builds the corresponding record class with the appropriate properties and attributes. As with XML and binary serialization in .NET, once you’ve created a record class— either by decorating its properties with attributes or by programmatically defining the record class—persisting a collection of such objects to disk or populating a collection of such objects from an existing text file is as easy as calling the library’s WriteFile or ReadFile methods. As the FileHelpers library serializes or deserializes the object or text file, it raises an event immediately before and after each record is processed. These events give you the opportunity to inspect or modify the data or cancel the operation prior to each read or write. FileHelpers includes asynchronous versions of the WriteFile and ReadFile methods, which are useful when working with especially large amounts of data. There’s also a file transform engine that assists in transforming the structure of a fixed-length or delimited file. In addition to classes for serializing the record class to disk, there are also classes for reading and writing records to and Send your questions and comments for Scott to toolsmm@microsoft.com. All prices confirmed at press time and are subject to change. The opinions expressed in this column are solely those of the author and do not necessarily reflect the opinions at Microsoft. August 2008 11

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

MSDN Magazine - August 2008 Toolbox CLR Inside Out Basic Instincts Cutting Edge Patterns in Practice Data 2.0 - Expose And Consume Data In A Web Services World Biztalk EDI - Build A Robust EDI Solution With BizTalk Server Silverlight - Create Animations With XAML And Expression Blend Write On! - Create Web Apps You Can Draw On With Silverlight 2 Wicked Code - Craft Custom Controls For Silverlight 2 Team System Foundations Windows With C++ Concurrent Affairs Going Places { End Bracket }

MSDN Magazine - August 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.