Welcome!

Microsoft Cloud Authors: Janakiram MSV, Yeshim Deniz, David H Deans, Andreas Grabner, Stackify Blog

Related Topics: Microsoft Cloud

Microsoft Cloud: Article

Questions and Answers on the .NET Compact Framework

Questions and Answers on the .NET Compact Framework

As many developers are already aware, the impending release of Visual Studio .NET 2003 will serve to bring the benefits of XML Web Services and the Microsoft Windows .NET Framework to smart devices via the inclusion of the .NET Compact Framework and Smart Device Projects. However, for those not already initiated, the following excerpts from Building Solutions with the .NET Compact Framework will explore the five basic questions that every developer asks when first thinking about the Compact Framework.

What Are the Goals of the Compact Framework?
Simply put, the goals of the Compact Framework (and Smart Device Projects) are fourfold:

  • To provide a portable (and small) subset of the Windows .NET Framework targeting multiple platforms. This includes the creation of a runtime engine, class libraries, and compilers for VB and C# that together are referred to as the .NET Compact Framework. This framework is not a simple port of the desktop version, but a complete rewrite designed to execute managed code on multiple CPU architectures and operating systems through an abstraction layer known as the Platform Adaption Layer (PAL). It is important to note that the Compact Framework was also designed to be a subset of the desktop version of the Framework. As a result, roughly 25% of the desktop types are represented in the Compact Framework.
  • Leverage VS .NET. Since VS .NET already provides a high productivity development environment, it is only natural that this environment should be utilized in developing mobile applications as well. To that end, the Smart Device Projects for VS .NET 2003 provide the project templates, emulator, debugger, and device integration to use the same IDE for desktop as for mobile development.
  • True Emulation. One of the requirements for developing robust (i.e., well-debugged) mobile applications is that they run as expected when installed on the device. To that end VS.NET includes emulators for Pocket PC and Windows CE that run exactly the same execution engine and class libraries as those installed on the device. In addition, the emulator supports localized packages for developing global applications. In this way, developers can be assured that the code they write and test with the emulator will execute correctly when deployed to the device.
  • Enable Web Services on Devices. Since XML Web Services are by definition device independent, they can be used from a variety of devices. By building support for consuming web services directly into the Compact Framework, developers can easily call web services.

    On Which Platforms Does It Run?
    Since 1992 Microsoft has produced a series of platforms (9 if our count is correct) built on the Windows CE operating system. A platform includes a specific set of hardware coupled with a version of Windows CE and associated software that makes it easier for developers and device manufacturers to target their solutions. The Compact Framework supports the Pocket PC 2000, 2002, and embedded Windows CE .NET 4.1 platforms. Although not officially supported, Compact Framework code also runs on Pocket PC Phone Edition devices that are a superset of Pocket PC 2002. Also not supported are smartphones such as the SPV from Orange.

    Because the Compact Framework is a managed environment, each device that executes applications written using the Compact Framework must have the framework installed. As of this writing, there were no devices shipping that included the Compact Framework as a standard component in RAM or in ROM. However, look for future devices running Windows CE .NET to include the runtime.

    What About ASP.NET Mobile Controls (aka the Mobile Internet Toolkit)?
    Many developers new to developing for mobility are at first confused by the differences between the Compact Framework and ASP.NET Mobile Controls. In a nutshell here are the primary differences.

  • The ASP.NET Mobile Controls are a server side technology whereas the Compact Framework is a client side technology. This means that code written using mobile controls must execute on a server, and not directly on the device, by producing markup language that is interpreted by the device using a browser or parser. Code written for the Compact Framework executes directly on the device using just-in-time (JIT) compilation and native execution.
  • The ASP.NET Mobile Controls are based on ASP.NET and use the ASP.NET HTTP runtime to handle and process requests via a set of ASP.NET server controls specially designed for small form factor devices. This means that mobile controls require an ASP.NET web server (IIS 5.0 or 6.0). The device issues requests that are processed on the web server by the controls producing markup language.
  • Both ASP.NET Mobile Controls and the Compact Framework are based on the desktop Framework and VS .NET. In the case of mobile controls, developers use VS .NET to write ASP.NET code using the ASP.NET server controls. The server side code is JIT compiled and executed on the web server by the common language runtime. In the case of the Compact Framework the code is written using SDP and subsequently downloaded to the device for JITting and execution using a compact version of the common language runtime.
  • The ASP.NET Mobile Controls are more flexible in that they can dynamically produce various markup languages depending on the requesting device they dynamically detect, including WML, cHTML, HTML, and XHTML (in Visual Studio .NET 2003 and the Framework v1.1). This means that mobile controls can support a broader range of devices (over 200 at last count) including wireless web phones, Pocket PCs, and virtually any device that supports HTTP and HTML. The ASP.NET Mobile Controls also include the ability to add device specific customizations so that as new devices come online their feature set can be identified.
  • Since code written for the Compact Framework is downloaded to the device, the Compact Framework supports connected, occasionally connected, and disconnected scenarios and supports local data storage using XML or SQL Server 2000 Windows CE Edition. ASP.NET Mobile Controls only support the former since an HTTP connection is required to request an ASP.NET page that uses the mobile controls. Basically, this means that mobile controls are targeted for building web sites for a broad variety of connected devices and at the same time not having to rewrite the vast majority of code to deal with differences between those devices.

    As a result you can (and in our estimation should) consider architecting and building your applications using the Compact Framework and SDP when the following are true.

  • You are developing code that will execute on the device, as opposed to applications developed with the ASP.NET Mobile Controls
  • Your applications must run in disconnected, connected, or occasionally connected modes
  • You are targeting the Pocket PC 2000, 2002 or embedded Windows CE .NET platforms

    What's Missing in the Compact Framework?
    In order to accommodate the restricted resources on smart devices the Compact Framework was designed as a subset of the desktop libraries and in fact includes just over 1,700 types, or roughly 25% of the desktop framework. As a result, developers familiar with the desktop Framework should not expect all the functionality they are accustomed to. The most important omissions are listed here:

  • ASP.NET. Because the Compact Framework is designed to support applications that execute on the device, it does not include any support for building web pages hosted on a web server running on the device.
  • COM Interop. Since the Windows CE operating system and the embedded Visual C++ (eVC) tool support creating COM components and ActiveX controls, it would be nice if the Compact Framework supported the same COM Interop functionality (complete with COM callable wrappers and interop assemblies) as does the desktop Framework. Unfortunately, COM Interop did not make it into the initial release of the Compact Framework. However, it is possible to create a DLL wrapper for a COM component using eVC++ and then call the wrapper using the Platform Invoke (PInvoke) feature of the Compact Framework, which allows native APIs to be called.
  • OleDb Access. The Compact Framework omits the System.Data.OleDb namespace and so does not support the ability to make calls directly to a database using the OleDb .NET Data Provider.
  • Generic Serialization. The desktop Framework supports binary serialization of any object through the use of the Serializable attribute, the ISerializable interface, and the XmlSerializer class in the System.Xml.Serialization namespace. This functionality is not supported in the Compact Framework. However, the Compact Framework does support serializing objects to XML for use in XML Web Services and serializing DataSet objects to XML.
  • Asynchronous Delegates. Delegates in both the desktop Framework and Compact Framework can be thought of as object-oriented function pointers. They are used to encapsulate the signature and address of a method to invoke at runtime. While delegates can be called synchronously, they cannot be invoked asynchronously and passed a callback method in the Compact Framework. However, it should be noted that asynchronous operations are supported for some of the networking functionality found in the System.Net namespace and when calling XML Web Services. In other cases, direct manipulation of threads or the use of a thread pool is required.
  • .NET Remoting. In the desktop Framework, it is possible to create applications that communicate with each other across application domains using classes in the System.Runtime.Remoting namespace. This technique allows for data and objects serialized to SOAP or a binary format to be transmitted using TCP or HTTP. This functionality is not supported (in part because Generic Serialization is not supported) in the Compact Framework where instead XML Web Services and IrDA can be used.
  • Reflection Emit. Although the Compact Framework does support runtime type inspection using the System.Reflection namespace, it does not support the ability to emit dynamically created MSIL into an assembly for execution.
  • Printing. Although the Compact Framework does support graphics and drawing, it does not support printing through the System.Drawing.Printing namespace.
  • XPath/XSLT. Support for XML is included in the Compact Framework and allows developers to read and write XML documents using the XmlDocument, XmlReader, and XmlWriter classes. However, it does not support executing XPath queries or performing XSL transformations.
  • Server-side Programming Models. As you would expect, the Compact Framework also does not support the server-side programming models including System.EnterpriseServices (COM+), System.Management (WMI), and System.Messaging (MSMQ).
  • Multi-module Assemblies. The desktop Framework supports the ability to deploy an assembly as a collection of files. This is useful for creating assemblies authored with multiple languages. This feature is not supported in the Compact Framework where a single file (.exe or .dll) represents the entire assembly.

    However, the Compact Framework does support two additional namespaces to support features particular to smart devices (see Table 1).

    In addition, support for the IrDA protocol has been included in the Compact Framework and exposed in the six classes found in the System.Net.Sockets and the System.Net namespaces.

    What Do Developers Need to Learn to Use the Compact Framework Effectively?
    Although VB 6.0 and embedded VB (eVB) developers will feel fairly comfortable with the VB syntax used in SDP, the object-oriented nature of the Compact Framework means that developers need to have a firm grounding in OO concepts in order to maximize their productivity.

    For example, the class libraries in the Compact Framework make extensive use of both implementation and interface inheritance. Developers familiar with these concepts can not only more easily understand the framework, but can write polymorphic code using the framework that is more maintainable and flexible than the component based development typically done in eVB. In the long run, using OO in their own designs allows developers to write less code and make the code that they do write more reusable. Therefore, to take maximum advantage of OO, however, a development organization should also get up to speed on the use of design patterns.

    Of course, because of its close association with the .NET Framework, existing Framework developers will also have a leg up.

    SIDEBAR

    Title:
    Building Solutions with the .NET Compact Framework

    Authors:
    Jon Box and Dan Fox

    Publisher:
    Addison-Wesley

    ISBN:
    0321197887

    Availability: June 2003

  • More Stories By Jon Box

    Jon Box is an Architect Evangelist in Developer & Platform Evangelism with the Microsoft Corporation. He coauthored Building Solutions with the Microsoft .NET Compact Framework, published by Addison-Wesley, and blogs at http://blogs.msdn.com/jonbox/default.aspx.

    Comments (0)

    Share your thoughts on this story.

    Add your comment
    You must be signed in to add a comment. Sign-in | Register

    In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


    @ThingsExpo Stories
    Widespread fragmentation is stalling the growth of the IIoT and making it difficult for partners to work together. The number of software platforms, apps, hardware and connectivity standards is creating paralysis among businesses that are afraid of being locked into a solution. EdgeX Foundry is unifying the community around a common IoT edge framework and an ecosystem of interoperable components.
    In his session at 21st Cloud Expo, Carl J. Levine, Senior Technical Evangelist for NS1, will objectively discuss how DNS is used to solve Digital Transformation challenges in large SaaS applications, CDNs, AdTech platforms, and other demanding use cases. Carl J. Levine is the Senior Technical Evangelist for NS1. A veteran of the Internet Infrastructure space, he has over a decade of experience with startups, networking protocols and Internet infrastructure, combined with the unique ability to it...
    "MobiDev is a software development company and we do complex, custom software development for everybody from entrepreneurs to large enterprises," explained Alan Winters, U.S. Head of Business Development at MobiDev, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    "Space Monkey by Vivent Smart Home is a product that is a distributed cloud-based edge storage network. Vivent Smart Home, our parent company, is a smart home provider that places a lot of hard drives across homes in North America," explained JT Olds, Director of Engineering, and Brandon Crowfeather, Product Manager, at Vivint Smart Home, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    "IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
    "Akvelon is a software development company and we also provide consultancy services to folks who are looking to scale or accelerate their engineering roadmaps," explained Jeremiah Mothersell, Marketing Manager at Akvelon, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
    Large industrial manufacturing organizations are adopting the agile principles of cloud software companies. The industrial manufacturing development process has not scaled over time. Now that design CAD teams are geographically distributed, centralizing their work is key. With large multi-gigabyte projects, outdated tools have stifled industrial team agility, time-to-market milestones, and impacted P&L stakeholders.
    Gemini is Yahoo’s native and search advertising platform. To ensure the quality of a complex distributed system that spans multiple products and components and across various desktop websites and mobile app and web experiences – both Yahoo owned and operated and third-party syndication (supply), with complex interaction with more than a billion users and numerous advertisers globally (demand) – it becomes imperative to automate a set of end-to-end tests 24x7 to detect bugs and regression. In th...
    "Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
    "There's plenty of bandwidth out there but it's never in the right place. So what Cedexis does is uses data to work out the best pathways to get data from the origin to the person who wants to get it," explained Simon Jones, Evangelist and Head of Marketing at Cedexis, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5–7, 2018, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buye...
    SYS-CON Events announced today that Telecom Reseller has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
    It is of utmost importance for the future success of WebRTC to ensure that interoperability is operational between web browsers and any WebRTC-compliant client. To be guaranteed as operational and effective, interoperability must be tested extensively by establishing WebRTC data and media connections between different web browsers running on different devices and operating systems. In his session at WebRTC Summit at @ThingsExpo, Dr. Alex Gouaillard, CEO and Founder of CoSMo Software, presented ...
    WebRTC is great technology to build your own communication tools. It will be even more exciting experience it with advanced devices, such as a 360 Camera, 360 microphone, and a depth sensor camera. In his session at @ThingsExpo, Masashi Ganeko, a manager at INFOCOM Corporation, introduced two experimental projects from his team and what they learned from them. "Shotoku Tamago" uses the robot audition software HARK to track speakers in 360 video of a remote party. "Virtual Teleport" uses a multip...
    A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, whic...
    SYS-CON Events announced today that Evatronix will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Evatronix SA offers comprehensive solutions in the design and implementation of electronic systems, in CAD / CAM deployment, and also is a designer and manufacturer of advanced 3D scanners for professional applications.
    Leading companies, from the Global Fortune 500 to the smallest companies, are adopting hybrid cloud as the path to business advantage. Hybrid cloud depends on cloud services and on-premises infrastructure working in unison. Successful implementations require new levels of data mobility, enabled by an automated and seamless flow across on-premises and cloud resources. In his general session at 21st Cloud Expo, Greg Tevis, an IBM Storage Software Technical Strategist and Customer Solution Architec...
    To get the most out of their data, successful companies are not focusing on queries and data lakes, they are actively integrating analytics into their operations with a data-first application development approach. Real-time adjustments to improve revenues, reduce costs, or mitigate risk rely on applications that minimize latency on a variety of data sources. In his session at @BigDataExpo, Jack Norris, Senior Vice President, Data and Applications at MapR Technologies, reviewed best practices to ...
    An increasing number of companies are creating products that combine data with analytical capabilities. Running interactive queries on Big Data requires complex architectures to store and query data effectively, typically involving data streams, an choosing efficient file format/database and multiple independent systems that are tied together through custom-engineered pipelines. In his session at @BigDataExpo at @ThingsExpo, Tomer Levi, a senior software engineer at Intel’s Advanced Analytics gr...