Mobile Applications with the 'NET Compact Framework

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Mobile Applications with the .NET Compact
Framework

• Twice IT TrainingAlex Thissen

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Agenda

• Mobile applications
• Smart Device Extensions
• Whats new in
• Visual Studio.NET 2003
• Compact Framework
• Data options
• XML Web Services
• SQL Server CE 2.0

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.NET Development Platform for Devices overview
Smart Device Extensions
Visual Studio .NET
.NET Framework
Server-side Web Apps
Client-sideRich Apps
Local Code
ASP.NET Web Pages
Mobile Web Browser
.NET CompactFramework
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Why SDE instead of MIT?

• MIT does not work offline
• Web pages do not have powerful UI
• SDE can use full power of processing
• Leverage SQL Server CE for data storage

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SDE features of VS.NET 2003

• Essentially same experience as Desktop
• New project templates (Windows CE en Pocket PC)
  voor VB.NET en C
• Introduces non-graphical application
• Only support for languages C and VB.NET
• New Project properties and Device Options
• Emulators for any device image
• Pocket PC and Windows CE.NET 4.0 included
• Remote on-device debugging
• Samples and documentation

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.NET Compact Framework
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Compact Framework architecture
.NET Compact Framework CLR
Applications
App Domain Host
Execution Engine (MSCOREE.DLL)
Platform Adaptation Layer
Host Operating System
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Whats the same?

• Common Language Runtime
• Garbage Collection
• JIT compilation of MSIL
• Type safety
• Exception manager
• Common Type System (any language)
• Platform Invocation enables calls to CE Win32
  Native API
• C has 100 language compatibility

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Whats different?

• COM Interopability not present
• No support for writing a COM object
• Write your own native wrapper classes and use
  P/Invoke to call wrapper
• Only 25 of class libraries present (less classes
  and overloaded methods)
• Only remoting option is client-side web services
• No ASP.NET or .NET Remoting
• No generic serialization

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Whats different? (continued)

• No reflection emit
• Cannot create native images (pre-JIT)
• No asynchronous delegates
• Cant use or make ActiveX controls

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Mobile applications

• This session has focus on working with data
• No attention to tools and utility apps
• Device must be mobile, not just wireless take
  your data with you if necessary
• Connection state possibilities
• Permanent connection to network
• Occasional connection (docked or wireless)
• Switching from connected to not connected
  should be easy or transparent to user

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Working with mobile data

• Accessing remote data
• Networking, ADO.NET Providers or XML Web Services
• Accessing local data
• ADO.NET DataSet or XML files
• Caching local data when offline
• SQL Server CE, ADO.NET persistence
• Synchronization of data when online
• ActiveSync, SQL Server CE Synchronization

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Networking Support

• Sockets
• Synchronous and asynchronous
• Multiple protocols
• Streams
• Built on top of sockets
• Synchronous and asynchronous
• HTTP request and response
• Use stream model
• Requires no user knowledge of HTTP

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Infrared support

• New classes for Infrared use
• namespaces System.Net and .Sockets
• IrDAClient, IrDADeviceInfo, IrDAEndPoint
• Use client to connect to endpoint
• Retrieve stream

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Data Access options
Windows CE SQL CE .NET Compact Framework
DataSet
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Using XML Web Services

• Web Service client fully supported on device
• Only Basic and Digest authentication
• Use Secure Sockets Layer (SSL) for secure
  communication
• All types of encoding
• Just add Web Reference in VS.NET 2003
• Generates regular SoapHttpClientProtocol wrapped
  proxy
• Instantiate proxy and call methods

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Supported XML Classes

• XmlDocument
• Parses all data in document to in-memory tree
• Random access to any part of tree
• Higher memory requirements, but offers more
  functionality
• XmlTextReader/Writer
• Forward-only reader and writer of XML data
• Better performance, no in-memory caching
• Low memory requirements even for large documents

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ADO.NET Providers

• Two providers come with .NET CF
• SqlServerCE
• SqlClient (no Windows Integrated Security)
• Sql Server Client provider works just like for
  the desktop
• Must have a permanent connection to backend
  server (not useful for offline support)
• Subset of classes are available
• Could write your own custom provider

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SQL Server CE 2.0

• On device mini SQL Server
• Only one concurrent connection allowed
• One file databases (.sdf files)
• Comes with a Query Analyzer
• Two main mechanisms to work with backend data
• SQL CE Replication
• SQL CE Remote Data Access (RDA)

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SQL Server CE 2.0 (continued)

• Install size approximately 800kB
• Supported platforms
• Windows CE 3.0 (Pocket PC 2000/2002, Handheld PC
  2000, Windows CE.NET 3.0/4.x)
• No longer support for Windows CE 2.x (PalmPC and
  HandheldPC 2.x)
• New from SQL CE 1.0
• Parameter queries (only unnamed)
• Better exception support (SqlCeException)
• Configuration Wizard

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SQL CE Storage Architecture
.NET CF / Managed Stack
Native/Unmanaged Stack
VS.NET (VB.NET, C)
ADO.NET
Ethernet
eVB 3.0
eVC 3.0/4.0
SQL Server CE Data Provider
SQL Server Client Data Provider
TDS
ADO CE v3.1
Well Connected
CLR / .NET CF
OLEDB CE
OLEDB / Replication API
802.11b, CDPD, GSM, CDMA, TDMA, etc.
SQL CE Edition v2.0
Data Provider
Client Agent Replication and RDA
IIS
Server Agent Replication and Remote Data Access
OLEDB
QP/Cursor Engine/ES
HTTP
OLEDB
Storage EngineReplication Tracking
Occasionally Connected
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SQL CE Replication

• Use SQL Server 2000 to create a publication of
  data for subscribers
• Conflict resolution
• Smart updates with delta changes in both
  directions
• Replicate data to device
• Subscriptions can be copied for easy deployment
  onto many devices
• Must use Merge replication
• SqlCeReplication managed class
• Add subscription of device to backend server
• Synchronize method brings downs entire database
  schema (indexes and relations) on first sync and
  changes on subsequent syncs

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Remote Data Access

• Gives more direct access to backend server
• Server can be SQL Server 6.5 SP5 or higher
• Push and pull for every table
• Code your own relational integrity into database
• SqlCeRemoteDataAccess managed object
• Three methodsPush, Pull and SubmitSql

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RDA Pull

• Pull method gets a single table from backend SQL
  Server
• Must delete existing table before pull
• Use SqlCeCommand to access SQL Server CE
• SELECT COUNT() FROM INFORMATION_SCHEMA.TABLES
  WHERE TABLE_NAMEOrders
• DROP TABLE Orders
• Must delete existing table before pull
• Specify whether to use batching or not
• No server configuration required

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RDA Push

• Use Push to update backend server with data from
  SQL CE database
• Error table is used to store update errors during
  Push
• No concurrency conflict detection!
• Error table has a row for each error
• Examine errors from table and resolve conflicts
• Baching option
• On all updates must succeed
• Off row-level conflict detection

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RDA SubmitSQL

• Run SQL statements directly on database server
• SQL statement cannot return rows
• All action occurs on backend server
• No local connection is needed

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Debugging

• Emulator is faster than device
• Device may have proprietary hardware
• Leave emulator open for faster startup
• Avoid Smart Minimize of PocketPC
• if DEBUG this.MinimizeBox falseendif
• Do not use Debug.Write for PocketPC
• Install loopback adapter for connectivity

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Deployment

• Easily deploy applications with CAB files
• Installs into Program Files directory
• Use .inf file to specify
• Directories, files, settings and configurations
• Can be found in obj folder of project
• Create customized versions under a different name
  and change BuildCab.bat
• Optional Setup.dll to further control setup
  process

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Resources

• Links
• http//www.microsoft.com/sql/CE/default.asp
• MSDN Library .NET Compact Framework
• MSDN Library Pocket PC and SmartPhone
• Books
• Microsoft .NET Compact Framework (Core Reference)
  
• The Definitive Guide to the .NET Compact
  Framework Not yet released

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Summary

• Compact Framework is subset of real .NET
  Framework
• Smart Device Extensions make programming
  essentially same as desktop
• Inherent differences for mobile app as opposed to
  desktop apps
• Loads of data access options

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Questions and Answers

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