Application Level Exception Handling in ASP.NET

This can be done in Global.asax within Application_Error method.

void Application_Error(object sender, EventArgs e)
{
    Exception ex = Server.GetLastError();
 
    if (ex.GetType() == typeof(HttpUnhandledException))
    {
        if (ex.Message.Contains("NoCatch") ||
ex.Message.Contains("maxUrlLength") ||
ex.Message.Contains("File does not exist."))
            return;
           
     
        Response.Write("~/Error.aspx");
    }

    Server.ClearError();
}

Reference: http://msdn.microsoft.com/en-us/library/24395wz3.aspx

Difference Between Sql Server VARCHAR and NVARCHAR Data Type

• varchar : Non-Unicode variable length character type
• nvarchar : Unicode variable length character type

Note: nvarchar can store both non-Unicode and Unicode characters(Example: Japanese, Korean)

Reference: http://sqlhints.com/2011/12/23/difference-between-varchar-and-nvarchar/

Relationships in SQL Server

One-To-Many

• One DeviceClass can have many DeviceTypes
• Key symbol represent one, infinity symbol represent many
• Note: You don’t have to have many. 

Many-To-Many

• Not as common as One-To-Many
• Many-To-Many relationship is expressed with help of junction tables
• A table name with a joint name of two tables

One-To-One

• Least commonly used relationship
• One row in one tables is related to, One row in other table

Reference: https://www.youtube.com/watch?v=4q-keGvUnag

Is C# a 100% Object Oriented Programming Language?

C# is NOT a pure object oriented programming language. 

Object oriented language should support:

1. Encapsulation
2. Polymorphism
3. Inheritance
4. All predefined type are objects
5. All operations performed by sending messages to objects
6. All user-defined types are objects

C# does not support point#4 & 5. 

In C#, predefined type can be struct. Example: integer > public struct Int32

So C# does not qualify as pure object oriented language.

Reference:

• http://www.jvoegele.com/software/langcomp.html
• http://stackoverflow.com/questions/3356464/is-c-sharp-a-100-object-oriented-programming-language

.NET Framework 4 Features

Background garbage collection:

• Provides background garbage collection 
• Provide better performance.
• It replaces concurrent garbage collection.

ETW (event tracing for windows):

• This determines processor usage and memory usage estimates per app domain.

DLR (dynamic language run-time):

• Support with System.Dynamic namespace. 
• DLR built on top of CLR
• DLR supports dynamic languages (IronPython, IronRuby)

Parallel programming:

• Parallel programming is introduced
• PLINQ
• AsParallel 

Tuple:

• Data structure consists of multiple parts
• System.Tuple
• Maximum of 8 items supported

BigInteger: is introduced with 8 byte storage size. int is 4 byte.

Reference: core new features and improvements

ASP.NET:

New Chart control:

Routing:

• Built-in support for routing. 
• No need to specify physical file names.

Session:

• Introduced compression option for out-process session state (state server/ SQL Server)

JQuery:

• is included in script folder

WCF REST: Video blog from DotNetIQ

How to Expose WCF service with Multiple endpoints,How to Call WCF REST (JSON) & SOAP services from JQuery

http://www.dotnetiq.com/2012/01/how-to-expose-wcf-service-with-multiple.html

Windows Service observations

Scenario: A windows service actively monitor the replication status in StatusDB. On status change, windows service open the configuration file of QuickSet service/Standard webservice and modify it. Windows service will also restart the IIS in order to reflect the configuration file changes immediately. This helps Quickset service/Standard web services in pointing to StandbyDB/LiveDB automatically.


Note:

• Debugging windows service is a real bottleneck.
• Use Microsoft event log for logging purpose. Event viewer helps to navigate through logs.
• Test the code in console application, then move it to windows service
• It is better to use SQL server authentication when connecting from windows service to SQL Server. 
• If windows service runs under Local System, then it won't be able to create instance of SQL server connection. Service property > Log on > Select a network account.
• Polling has to be done in a different thread.

Reference:  

• http://www.codeproject.com/Articles/16615/How-to-Create-a-Simple-Polling-Service 

• http://stackoverflow.com/questions/7509522/connection-between-windows-service-and-sql-database