Pooling Wisely for Oracle Data Provider for .NET

Use the Decr Pool Size and Incr Pool Size properties wisely when you use ODP pooling.

Decr Pool Size Controls the number of connections that are closed when an excessive amount of established connections are unused, and Incr Pool Size Controls the number of connections that are established when all the connections in the pool are used.

When a connection pool is created, the connection-pooling service initially creates the number of connections defined by the Min Pool Size attribute of the ConnectionString, and then Incr/Decr pool size properties are used to maintain the connections pooled.

The values for Incr/Decr pool size should be based on your Min Pool Size and Max Pool Size values. Eg: "User Id=scott;Password=tiger;Data Source=oracle; Min Pool Size=10; Max Pool Size=1200;Connection Lifetime=120;Connection Timeout=60; Incr Pool Size=10; Decr Pool Size=5";

XmlSerializer Worries and Generating Typed Serializers

The simple constructors of XMLSerializer class caches the typed serializer once it is generated.

When you use XmlSeializer to serialize a type, XmlSerializer will create a dynamic assembly on the fly containing the serialization code. When XmlSerializer is invoked from your application,

• The XmlSerializer constructor will reflect the type you are passing to the XmlSerializer constructor, and generate the code for typed serializer for the same.
• The code is compiled by calling csc at run time
• The resulting assembly is loaded to the application domain, and is cached for future uses.

How ever, there is a known problem with XmlSerializer - some XMLSerializer constructors (other than the simple constructors) will regenerate the typed serializer assembly each time, instead of getting it back from the cache. In other words, XmlSerializer is not using the caching mechanism in every constructor - but only for simple constructors.

Anyway, it is a better practice to generate your serializers at compile time, instead of using XmlSerializer which effects in run time generation of typed serializers. Atleast, this will definitely improve your application performance during startup (for web applications). For desktop applications, you should use typed serializers.

You can use some typed serializer generators like SGen or Mvp.Xml.XGen to generate typed serializers. SGen is not very mature, because it fails to handle a couple of scenarios, and may skip some types with out any warning.

Mvp.Xml.XGen is better.What it does is, pass the type to generate the code to XmlSerializer at design time itself, and then stealing away the code generated by XmlSerializer (and optimize it a little bit), to compile the typed serializer code - and provide you the typed serializer at design time itself.

When you pass a type to XmlSerializer, the code generated can be fetched from the temp folder, provided you requested XmlSerializer constructor not to cleanup the code it has generated. For this, you've to add a hidden switch to your application config file - like

<configuration> <system.diagnostics> <switches> <add name="XmlSerialization.Compilation" value="4"/> </switches> </system.diagnostics> </configuration>

Unloading assembly from the Appdomain

It is pretty sad that Microsoft is not providing an ideal way to unload individual assemblies from an application domain :( Right now, if you want to unload individual assemblies, you have to create another app domain, and then load your assemblies to that, and unload the entire app domain once you are done. But this approach has few problems

• If you are loading your assembly to a separate application domain, you have to use remoting for cros app domain calls
• You don't really need a separate app domain to load and unload assemblies - because of performance reasons.

I've read an interesting blog entry from Jason Zanders here

Microsoft Surface

This should not be a post under .NET category, but still..

If you havn't heard much about Microsoft Surface http://www.surface.com/

The Surface SDK is not released yet, but I suspect it will heavily oriented towards .NET and Silverlight :)

Microsoft Enterprise Library - May 2007 CTP

Microsoft Enteprise Library May 2007 CTP release is available

You can get it from

http://msdn2.microsoft.com/en-us/library/aa480453.aspx

Also, don't miss this Power point presentations.

• What's New in Enterprise Library 3.x
• Enterprise Library 3.x: Overview
• Enterprise Library for .NET Framework 2.0: Overview
• Enterprise Library for .NET Framework 2.0: Core Architecture
• Introducing the Validation Application Block
• Introducing the Policy Injection Application Block

Microsoft Silverlight

If you havn't yet heard about Silverlight,

"Microsoft® Silverlight™ is a cross-browser, cross-platform plug-in for delivering the next generation of .NET based media experiences and rich interactive applications for the Web. Silverlight offers a flexible programming model that supports AJAX, VB, C#, Python, and Ruby, and integrates with existing Web applications. Silverlight supports fast, cost-effective delivery of high-quality video to all major browsers running on the Mac OS or Windows."

Here is more info - http://silverlight.net/

You can watch more details and tutorials here

http://silverlight.net/learn/learnvideos.aspx#video188

LINQ and C# 3.0

This months MSDN features LINQ (If you are not yet aware what is in store for the next release of .NET, LINQ is a dynamic querying framework that is tightly integrated to the next version of .NET)

Have a look at this MSDN article here

Orcas And Microsoft.NET 3.5

Orcas Beta and .NET 3.5 is in store for some time - You can download Microsoft.NET 3.0 from MSDN.

If you are still not aware about the story, See this whitepaper about Orcas here

Orcas Whitepaper - Click here For .NET 3.5 Click here For Orcas Click here

A GPS Tracer Application for Windows Mobile

I found a good article about creating a simple GPS tracer application for Windows Mobile, in Code Project. It shows

• Read data from any NMEA GPS device
• Read your position and print it to the screen
• Load and save your path
• Zoom in/out
• Pan on your path
• Center on the map
• Run in demo mode with randomly generated data

Very interesting. See http://www.codeproject.com/ce/GpsTracerAppWMCE5.asp for details

ASP.NET Videos

Have a look at these ASP.NET Videos in Microsoft Asp.net Website.

“How Do I?” with ASP.NET AJAX

“How Do I?” with ASP.NET

SQL Server 2005 Express for Beginners

Videos for ASP.NET 2.0 Beginners

“First Look” VideosVideos on Visual Studio 2005 Add-ins

Videos on Migrating to ASP.NET

Really good stuff.

SandCastle And NDoc - For .NET 2.0 Code Documentation

Recently, I was searching for some good tools for generating MSDN style documentation from C# code comments. Here are few tools I came across.

Sand Castle - Provided by Microsoft, with out much official support. But serves the purpose. May take some time to configure :) - See http://blogs.msdn.com/sandcastle/

NDoc For .NET 2.0 - I don't think it is an official release of NDoc, but this one can generate code comments for VS 2005 - See http://jonas.lagerblad.com/blog/?p=5 . When you try to open a VS 2005 solution, it may say Invalid Solution, but I got around this problem by simply dragging the dll file to the 'Select Assemblies To Document' listbox before building them.

Frameworks For .NET Development

Here is a little bit of information regarding some good frameworks, for .NET application development. Traditionally, we have the presentation layer, business logic layer, and the data logic layer. In these layers, things like Exception handling, logging etc can be common.

For example, Microsoft Enterprise Library blocks offers such common functionalities, as different functionality blocks.

The Enterprise Library consists of a Data Access Application Block. Though this provides a reusable pure data layer, it lacks the rich features of a true ORM. But because it has the backing of Microsoft and their legions of developers, many companies will adopt the Data Access Application Block as their standard platform. But still, to gain the real power, we need to look for some frameworks with much more features, than the Microsoft Data Access Application Block. Hence, let us have a look at some other frameworks- some of them are mainly for implementing data access logic and OR mapping, and others like AdapDev has much more features like support for advanced caching. Some of them (like EasyObject.NET) internally uses Microsoft Data Access Block for interfacing with the database.

1. Neo - Neo is a framework for .NET developers who want to write enterprise applications with an object-based domain model. It is well suited for domain-driven design and agile development. Pretty good for small apps See http://neo.codehaus.org/

2. nHibernate - NHibernate is a .NET based object persistence library for relational databases. It is a widely used OR persistant tool these days. It is inspired by Java hibernate. See http://wiki.nhibernate.org/display/NH/Home

3. MyGeneration DoodAds - DoodAds is an elegant .NET architecture available in C# and VB.NET and capable of supporting any .NET managed data provider. Currently dOOdads are available for Microsoft SQL, Oracle, Firebird, Access, PostgreSQL, VistaDB, SQLite, and MySQL . You can use MyGeneration Code Generator to generate DAL classes easily for DoodAds. See http://www.mygenerationsoftware.com/ . It is one of the great frameworks I've seen so far, with an elegant Dynamic Query support. Highly recommended.

4. EasyObjects.NET - EasyObjects.NET is an object relational mapper (ORM) architecture based on a combination of the popular MyGeneration dOOdads architecture and the Microsoft Enterprise Library. See http://easyobjects.tigris.org/

5. DataBlock - DataBlock is a Object Relational Mapping and persistence framework for .NET 2.0. - See http://www.voidsoft.ro/DataBlock/index.html

6. AdapDev.NET - Adapdev.NET is a robust enterprise framework that supplements the MS.NET framework. It's the foundation of Codus (OR Code generator) and Zanebug (A unit testing framework) providing the underlying code generation and unit testing engines. See http://www.adapdev.com/

7. Gentle.NET - Gentle.NET is an RDBMS independent object persistence framework. It features automatic SQL generation and object construction, an SQL factory for creating custom queries, DataView construction helpers, excellent performance and reasonably complete docs. See http://www.mertner.com/confluence/display/Gentle/Home

8. IBatis.NET - The iBATIS Data Mapper framework makes it easier to use a database with Java and .NET applications. iBATIS couples objects with stored procedures or SQL statements using a XML descriptor. Simple and elegant..See http://ibatis.apache.org/

Provider Pattern

I've published an article about creating a provider based framework here http://www.codeproject.com/useritems/providerframework.asp After reading this article, you'll be able to (1) Change your mindset a little bit, and start thinking about 'frameworks' instead of just 'code' (2) Understand a lot about practically applying provider pattern in your projects (3) Gain much knowledge regarding xml config files and providers