Exception Handling in WCF using Fault Contract

//Create Services Contract (Interface)
using System;
using System.Collections.Generic;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;

// NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService" in both code and config file together.
[ServiceContract]
public interface IService   //name of interface
{

[OperationContract]        // Name of Method
[FaultContract(typeof(MyReason))]
string GetData(int value);

}

[DataContract]
public class MyReason
{
[DataMember]
private string Reason;
public string MyCause { get; set; }
}

//class to implement Services Contract 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
using System.Data.SqlClient; 

// NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "Service" in code, svc and config file together.

public class Service : IService
{
  SqlConnection con;
  string ret;
  public string GetData(int r)
   {
     try
      {
         con = new SqlConnection("initial catalog=Tblname;data source=Dbname;integrated security=yes");
SqlCommand cmd = new SqlCommand("select name from student where seat_no=" + r + "", con);
con.Open();
SqlDataReader rd = cmd.ExecuteReader();
bool b = rd.Read();
if (b == false)
{
ret = null;
}
else
{
ret = rd["name"].ToString();
}

}

catch (Exception e1)
{
MyReason m = new MyReason();
m.MyCause = "he has internal pain in stomach";
throw new FaultException<MyReason>(m);
}
finally
{
con.Close();

}

return ret;
}
}

//Call That Services Client Side

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.ServiceModel;    //First Client Add ServiceModel NameSpace

public partial class Default2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void Button1_Click(object sender, EventArgs e)
{
try
 {
   int s1 = Convert.ToInt32(TextBox1.Text);

ServiceReference1.ServiceClient s=new 

ServiceReference1.ServiceClient();
string y = s.GetData(s1);
if (y == null)
{
Label1.Text = "Rec not found";
}
else
{
  Label1.Text = y;
}
}
catch (FaultException<ServiceReference1.MyReason> m)
{

Label1.Text = m.Detail.MyCause; //Services Error Here

}
}
}
//

create Custom Event in C#

using System;

public delegate void CarOwnerChanged(string o);
public class car
{

       public event CarOwnerChanged OwnerChanged;
       private string owner;

         public string car_owner
          {

           get
              {
                return owner;
              }

           set
              {
                 owner = value;
                  if (OwnerChanged != null)
                     {
                        OwnerChanged(owner);
                      }
                }

            }

}
class office
{

     public static void Main()
     {

         car Viru= new car();
          Viru.OwnerChanged+=new CarOwnerChanged(parking_call);
          Viru.car_owner = "Viru Maurya";
      }

      public static void parking_call(string ow)
       {
          Console.WriteLine(ow);
       }
}

Response.Redirect vs Server.Transfer

Response.Redirect vs Server.Transfer 

1.     ‘Response. Redirect’ sends message to the browser saying it to move to some different page, while ‘Server. Transfer’ does not send any message to the browser but rather it redirects the user directly from the server itself. So in case of ‘Server. Transfer’ there is no round trip while Response. Redirect has a round trip and hence puts extra load on server. 

2.     Using ‘Server. Transfer’ we cannot redirect to external websites or website pages. E.g. if your website is www.webcodeexpert.com then you cannot use ‘Server. Transfer’ to move to www.google.com but yes, you can move to internal pages  www.webcodeexpert.com/asp.net, i.e. within the websites. Cross server redirection is possible only by using ‘Response.Redirect’ i.e. it allows redirection to internal as well as external websites and website pages.

3.     With ‘Response. Redirect’ we can redirect the user to the both type of pages .html or .aspx e.g. Response. Redirect (“OtherPage.html”) OR Response. Redirect (“OtherPage.aspx”) But in case of ‘Server. Transfer’ we can redirect user to .asp or .aspx pages only e.g. Server. Transfer (“OtherPage.asp”) OR Server. Transfer (“OtherPage.aspx”) not to Server. Transfer (“OtherPage.html”).

4.     In ‘Server. Transfer’ URL doesn’t change but in case of ‘Response. Redirect’ URL changes.

5.     When we want to allow our website’s URL can be copied then ‘Response. Redirect’ is better but for security reasons ‘Server. Transfer’ is better because URL cannot be copied.

6.     ‘Response. Redirect’ has a round trip but ‘Server.Transfer’ has no round trip. (Roundtrip is the combination of a request being sent to the server and response being sent back to browser.)

7.     ‘Server. Transfer’ is a server process whereas ‘Response. Redirect’ is a client process.

8.     ‘Server.Transfer’ preserves Query String and Form Variables (optionally). ‘Response. Redirect’ doesn’t preserve Query String and Form Variables from the original request.

9.     ‘Server. Transfer’ is faster since there is one less round trip as compared to ‘Response. Redirect’. Transferring to another page using ’Server. Transfer’ conserves server resources. Instead of telling the browser to redirect, it simply changes the focus on the Web server and transfers the request. This means you don't get quite as many HTTP requests coming through, which therefore eases the pressure on your Web server and makes your applications run faster.

10. ‘Server. Transfer’ allow us to directly access the values, controls and properties of the previous page which we can’t do with ‘Response. Redirect’. The ’Server. Transfer’ method also has a second parameter—"preserveForm". If you set this to True, using a statement such as Server. Transfer ("OtherPage.aspx", True), the existing query string and any form variables will still be available to the page you are transferring to. For example, if your CurrentPage.aspx has a TextBox control called TextBox1 and you transferred to OtherPage.aspx with the preserveForm parameter set to True, you'd be able to retrieve the value of the original page’s TextBox control by referencing Request. Form ("TextBox1").

11. ‘Response. Redirect’ involves a roundtrip to the server whereas ‘Server. Transfer’ conserves server resources by avoiding the roundtrip. It just changes the focus of the web server to a different page and transfers the page processing to a different page. Roundtrip means in case of ‘Response. Redirect’ it first sends the request for the new page to the browser then browser sends the request for the new page to the web server only then a your page changes But in case of ‘Server. Transfer’ it directly communicate with the server to change the page hence it saves a roundtrip in the whole process.

Difference between Stored procedure and Function

Stored Procedure:

A stored procedure is a pre-compiled group of Transact-SQL statements .We can say a stored procedure is a prepared SQL code that we save so that we can reuse the code over and over again.  If a repetitive T-SQL task has to be executed within an application, then the best way for it is to create stored procedure.

               It is always recommended to create Stored Procedure instead of writing Inline queries so that we can just call the Stored Procedures whenever required instead of writing Inline queries again and again each time.

                You can also pass parameters to the stored procedure, so depending on what the need is the stored procedure can act accordingly based on the parameter values that were passed to it.

Function:

 Function in Sql Server is a Transact-SQL or common language runtime (CLR) routine that takes parameters, performs an action, and returns the result of that action as a value. The return value can either be a scalar (single) value or a table.

1.       Function can return only 1 value whereas Stored Procedure can return many values(maximum 1024)

2.       Functions can have only input parameters for it whereas Stored Procedures can have input/output parameters.

3.       Function takes one input parameter which is mandatory but Stored Procedure may take Zero to n input parameters.

4.       Functions can be used in a select statement where as Stored Procedures cannot.

5.       Functions can be called from Stored Procedure whereas Stored Procedures cannot be called from Function.

6.       Stored procedures are called independently, using the EXEC command, while functions are called from within another SQL statement.

7.       Functions must always return a value (either a scalar value or a table). Stored procedures may return a scalar value, a table value or nothing at all.

8.       Stored Procedure can be used to read and modify data but function can only read data.

9.       Stored Procedure allows SELECT as well as DML (Data Manipulation Language) statements like INSERT/UPDATE/DELETE in it whereas Function allows only SELECT statement in it.

10.   Procedures cannot be utilized in a SELECT statement whereas Function can be embedded in a SELECT statement.

11.   Stored Procedures cannot be used as an inline with a select statement while Functions can. 

12.   Stored procedures are compiled for first time and compiled format is saved and executes compiled code whenever it is called. But Function is compiled and executed every time it is called. 

13.   Stored Procedures cannot be used in the SQL statements anywhere in the WHERE/HAVING/SELECT section whereas Function can be.

14.   Exception can be handled by try-catch block in a Procedure whereas try-catch block cannot be used in a Function.

15.   Stored Procedure allows Transaction Management whereas Function doesn’t.

16.   Stored procedures can be used to change server configuration settings (in terms of security-e.g. setting granular permissions of user rights) whereas function can't be used for this

17.   The Stored Procedures can perform certain tasks in the database by using insert, delete, update and create commands but in Function you can’t perform use these commands. 

18.   Normally the Stored procedures are used to process certain task but the Functions are used to compute the values i.e. we can pass some value as input and then it perform some task on the passed value and return output. 

19.   Stored Procedures can be executed using Execute or Exec command where as Functions can run as an executable file. 

20.   Functions can be used as user defined data types in create table but procedures cannot.