Jump Start to be Software Developer (Session-3)

Speech on “Jump Start to be Software Developer (Session 3)” .

Topic: ASP.NET (Part – 1)
Technical Speaker: Md. Mahedee Hasan
Venue: Microsoft Bangladesh
Organized by: Microsoft Bangladesh & Tech Forum
Date: 18 May, 2014

Introduction to Web services with ASP.NET

What is Web Services?

Web service is a method of communication between two web based application using XML, SOAP, WSDL and UDDI open standards over an internet protocol backbone. Web service can convert your application into web application which can publish its function or message to the rest of the world). Web service are-

Web services are application components
Web services communicate with open protocols
Web services are self-contained and self-describing
Web services can be discovered using UDDI (*4)
Web services can be used by other applications
XML is the basis of web services

Why Web Services?

Different web applications in the web want to interact with each other. Such as application can share data, can invoke method of other application. So, how can you solve this? It will also be a great problem if applications are in different platform and language. Web service solves the above issues.

By using Web services, your application can publish its function or message to the rest of the world. Web services use XML to code and to decode data, and SOAP to transport it (using open protocols). With Web services, your accounting department’s Win 2k server’s billing system can connect with your IT supplier’s UNIX server

Web services have two types of uses:

Reusable Application Component – currency conversion, weather reports, language translation.Connect Existing Software – Web services can help to solve the interoperability problem by giving different applications a way to link their data.

How does it work?

The basic web service platform is XML + HTTP. Web service elements are –

SOAP – Simple Object Access Protocol
UDDI – Universal Description, Discovery and Integration
WSDL – Web Service Description Language

With ASP.net, you do not have to write SOAP and WSDL documents. ASP.net automatically creates SOAP and WSDL documents.

Example:

Simple Addition Method: Here I have tried to represent web service before you by a simple add method which takes two parameter as two integer value and it returns the addition of these two.

Step 1: Create Asp.net Web service

1.Create an Asp.net website.

Click right button on asp.net web site.
Click on add new Item.
Select Web service like the below screen.

Right click on WebService.asmx and select view code. You will see the following code snippet. It should be mentioned here that I have created my web service named WebService which you have already seen in previous screen.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Services;

///

/// Summary description for WebService

///

[WebService(Namespace = "http://tempuri.org/")]

[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]

// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.

// [System.Web.Script.Services.ScriptService]

public class WebService : System.Web.Services.WebService {

public WebService () {

//Uncomment the following line if using designed components

//InitializeComponent();

}

[WebMethod]

public string HelloWorld()

{

return "Hello World";

}

}

Simply add a Method name Add as like below.

/// Copyright : Copyright© mahedee.hasan@gmail.com. All rightsreserved.

/// NameSpace :

/// Class : WebService

/// Inherits : System.Web.Services.WebService

/// Author : Md. Mahedee Hasan

/// Purpose : This is a simple web service to add two number

/// Creation Date : 21/01/2012

/// =========================================================================================

/// || Modification History ||

/// ------------------------------------------------------------------------------------

/// Sl No. Date: Author: Ver: Area of Change:

/// 1. 21/01/2012 Mahedee 1.0 Created

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Services;

///

/// Summary description for WebService

///

[WebService(Namespace = "http://tempuri.org/")]

[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]

// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.

// [System.Web.Script.Services.ScriptService]

public class WebService : System.Web.Services.WebService {

public WebService () {

//Uncomment the following line if using designed components

//InitializeComponent();

}

[WebMethod]

public string HelloWorld()

{

return "Hello World";

}

[WebMethod]

public int Add(int firstVal, int secondVal)

{

return firstVal + secondVal;

}

}

.Click right button on WebService.asmx and select Set As Start Page
Run Project or press F5. You will see the following screen.

9. Click Add method, you will see the following screen.

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10. Suppose I input two value 12 and 30. Click Invoke.

.11. After clicking Invoke you will get the addition of two values as XML format.

Now your web service is ready to use. We have to use web service in various ways. In the next step I will show how to access web service from client page.

Step 2: Create a client page and access web service.

There are many ways to consume web service. Here is an example of HTML-POST protocol which is one of the ways of consuming web service.

1. Create a aspx/html page. I have used here an aspx page name “ClientForm.aspx”.
2. Add the following tags in aspx source.
3. In action attribute of form tag, I have used localhost because I have already hosted it. You can simply use “http://localhost:5143/Web/WebService.asmx/Add” in action attribute instead of present value in action attribute if you didn’t host website in your local machine. Here 5143 can vary.





input>

input>

 input>

div>

form>

4. Click right button on ClientForm.aspx and select Set As Start Up page.
5. Run your project.
6. You will see the following screen.

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7. Enter two values of two textbox.
8. Press Enter you will get the result in xml format.

25int>

This is the basic example and web service. You will see more about web service next.

Notes:

XML provides a language which can be used between different platforms and programming languages and still express complex messages and functions.
SOAP: The HTTP protocol is the most used Internet protocol.

SOAP is an XML-based protocol to let applications exchange information over HTTP.

Or more simple: SOAP is a protocol for accessing a Web Service.

SOAP stands for Simple Object Access Protocol
SOAP is a communication protocol
SOAP is a format for sending messages
SOAP is designed to communicate via Internet
SOAP is platform independent
SOAP is language independent
SOAP is based on XML
SOAP is simple and extensible
SOAP allows you to get around firewalls
SOAP is a W3C standard

WSDL:

WSDL is an XML-based language for locating and describing Web services.

WSDL stands for Web Services Description Language
WSDL is based on XML
WSDL is used to describe Web services
WSDL is used to locate Web services
WSDL is a W3C standard

UDDI:

UDDI is a directory service where companies can register and search for Web services.

UDDI stands for Universal Description, Discovery and Integration
UDDI is a directory for storing information about web services
UDDI is a directory of web service interfaces described by WSDL
UDDI communicates via SOAP
UDDI is built into the Microsoft .NET platform

�

A Simple Demonstration with ASP.net GridView

GridView is a powerful control of ASP.net. Here I tried to demonstrate gridview with a simple project. I have stored employee information then displayed it in gridview and insert, update and delete employee information.
Step 1: Create a table name hrm_employee and insert some sample data in it.

--Create Table : hrm_employee---
CREATE TABLE hrm_employee
(
emp_gid INT PRIMARY KEY IDENTITY,
emp_fullnm VARCHAR(100),
emp_nicknm VARCHAR(50),
emp_designation VARCHAR(100)
)

---Insert data ito table: hrm_employee----

-- Insert data i.e. row-1 ---
INSERT INTO hrm_employee
(
emp_fullnm
, emp_nicknm
, emp_designation
)
VALUES
(
'Md. Mahedee Hasan'
, 'Mahedee'
, 'Senior Software Engineer'
)

-- Insert data i.e. row-2 ---
INSERT INTO hrm_employee
(
emp_fullnm
, emp_nicknm
, emp_designation
)
VALUES
(
'Md. Asrafuzzaman'
, 'Emon'
, 'Senior Software Engineer'
)

-- Insert data i.e. row-3 ---
INSERT INTO hrm_employee
(
emp_fullnm
, emp_nicknm
, emp_designation
)
VALUES
(
'Md. Khondakar Enamul Haque'
, 'Rony'
, 'Broadcast Engineer'
)

Step 2: Create an ASP.net website with 3 Layers – DAL for data access layer, BLL for Business Logic Layer and presentation Layer. Also create another layer name Model for mapping with data.

Step 3: Create connection string in web.config file.

Step 4: Create Images Folder and store icon edit_icon.gif for edit and icon_remove.png for delete.
Step 5: Create EmployeeInfo model class.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

///
/// Model class of EmployeeInfo
///

public class EmployeeInfo
{
public int EmpGid { get; set; }
public string EmpFullNm { get; set; }
public string EmpNickNm { get; set; }
public string EmpDesignation { get; set; }
}

Step 6: Create a DBConnector Class for connecting with database in DAL.

/// Class : DBConnector
/// Author : Md. Mahedee Hasan
/// Purpose : For Connecting with database
///Creation Date : 21/04/201
/// ==================================================================================================
/// || Modification History ||
/// -------------------------------------------------------------------------------------------------
/// Sl No. Date: Author: Ver: Area of Change:
///
///**************************************************************************************************

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;

public class DBConnector
{
private string connectionString = null;
private SqlConnection sqlConn = null;
private SqlCommand cmd = null;

public DBConnector()
{
connectionString = ConfigurationManager.ConnectionStrings["SQLServerConnectionString"].ToString();
}

public SqlCommand GetCommand()
{
cmd = new SqlCommand();
cmd.Connection = sqlConn;
return cmd;
}

public SqlConnection GetConn()
{
sqlConn = new SqlConnection(connectionString);
return sqlConn;
}

}

Step 7: Create EmployeeInfoDAL class in DAL layer for accessing data (Employee Information related) from database.

/// Class : EmployeeInfoDAL
/// Author : Md. Mahedee Hasan
/// Purpose : Retreving data from database
/// Creation Date : 21/04/2012
/// ==================================================================================
/// || Modification History ||
/// -----------------------------------------------------------------------------
/// Sl No. Date: Author: Ver: Area of Change:
///
/// ***************************************************************************

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Data.SqlClient;

///
/// Summary description for EmployeeInfoDAL
///

public class EmployeeInfoDAL
{

private SqlConnection sqlConn;
private SqlCommand cmd;
private readonly DBConnector objDBConnector;

///
/// Constructor
///

public EmployeeInfoDAL()
{
objDBConnector = new DBConnector();
sqlConn = objDBConnector.GetConn();
cmd = objDBConnector.GetCommand();
}

///
/// Get all employee information
///
///

public DataTable GetEmployeeInfoAll()
{
DataTable tblEmpInfo = new DataTable();
SqlDataReader rdr = null;

cmd.CommandType = CommandType.Text;

cmd.CommandText = "SELECT emp_gid, emp_fullnm, emp_nicknm, emp_designation FROM hrm_employee";

try
{
if (sqlConn.State == ConnectionState.Closed)
sqlConn.Open();

rdr = cmd.ExecuteReader();
tblEmpInfo.Load(rdr);
}
catch (Exception exp)
{
throw (exp);
}
finally
{
if (sqlConn.State == ConnectionState.Open)
sqlConn.Close();
}

return tblEmpInfo;

}

///
/// Insert Employee information
///
///
///

public string InsertEmployeeInfo(EmployeeInfo objEmployeeInfo)
{
string msg = String.Empty;

int noOfRowEffected = 0;

try
{
if (sqlConn.State == ConnectionState.Closed)
sqlConn.Open();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "INSERT INTO hrm_employee(emp_fullnm , emp_nicknm , emp_designation)"
+ " VALUES('" + objEmployeeInfo.EmpFullNm + "','" + objEmployeeInfo.EmpNickNm + "','" + objEmployeeInfo.EmpDesignation + "')";

noOfRowEffected = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
}
catch (Exception exp)
{
throw (exp);
}
finally
{
if (sqlConn.State == ConnectionState.Open)
sqlConn.Close();
}

if (noOfRowEffected > 0)
return "Employee information saved successfully!";
else
return msg;
}

///
/// Update employee information
///
///
///

public string UpdateEmployeeInfo(EmployeeInfo objEmployeeInfo)
{
string msg = String.Empty;

int noOfRowEffected = 0;

try
{
if (sqlConn.State == ConnectionState.Closed)
sqlConn.Open();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "UPDATE hrm_employee SET emp_fullnm = '" + objEmployeeInfo.EmpFullNm +
"',emp_nicknm = '" + objEmployeeInfo.EmpNickNm + "', emp_designation = '" + objEmployeeInfo.EmpDesignation
+ "' WHERE emp_gid = " + objEmployeeInfo.EmpGid;

noOfRowEffected = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
}
catch (Exception exp)
{
throw (exp);
}
finally
{
if (sqlConn.State == ConnectionState.Open)
sqlConn.Close();
}

if (noOfRowEffected > 0)
return "Employee information updated successfully!";
else
return msg;
}

///
/// Delete employee information
///
///
///

public string DeleteEmployeeInfo(int empGid)
{
string msg = String.Empty;

int noOfRowEffected = 0;

try
{
if (sqlConn.State == ConnectionState.Closed)
sqlConn.Open();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "DELETE FROM hrm_employee"
+ " WHERE emp_gid = " + empGid;

noOfRowEffected = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
}
catch (Exception exp)
{
throw (exp);
}
finally
{
if (sqlConn.State == ConnectionState.Open)
sqlConn.Close();
}

if (noOfRowEffected > 0)
return "Employee information deleted successfully!";
else
return msg;
}
}

Step 8: Create EmployeeInfoBLL in BLL for writing business logic and accessing data by DAL.

/// Class : EmployeeInfoBLL
/// Author : Md. Mahedee Hasan
/// Purpose : Business Logic Layer - Write business logic here
/// Creation Date : 21/04/2012
/// ==================================================================================================
/// || Modification History ||
/// -------------------------------------------------------------------------------------------------
/// Sl No. Date: Author: Ver: Area of Change:
///
/// **************************************************************************************************

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;

///
/// Summary description for EmployeeInfoBLL
///

public class EmployeeInfoBLL
{
public EmployeeInfoBLL()
{

}

public DataTable GetEmployeeInfoAll()
{
try
{
EmployeeInfoDAL objEmployeeInfoDAL = new EmployeeInfoDAL();
return objEmployeeInfoDAL.GetEmployeeInfoAll();
}
catch (Exception exp)
{
throw (exp);
}
}

public string SaveEmployeeInfo(EmployeeInfo objEmployeeInfo)
{
try
{
EmployeeInfoDAL objEmployeeInfoDAL = new EmployeeInfoDAL();
return objEmployeeInfoDAL.InsertEmployeeInfo(objEmployeeInfo);
}
catch (Exception exp)
{
throw (exp);
}
}

public string EditEmployeeInfo(EmployeeInfo objEmployeeInfo)
{
try
{
EmployeeInfoDAL objEmployeeInfoDAL = new EmployeeInfoDAL();
return objEmployeeInfoDAL.UpdateEmployeeInfo(objEmployeeInfo);
}
catch (Exception exp)
{
throw (exp);
}
}

public string RemoveEmployeeInfo(int empGid)
{
try
{
EmployeeInfoDAL objEmployeeInfoDAL = new EmployeeInfoDAL();
return objEmployeeInfoDAL.DeleteEmployeeInfo(empGid);
}
catch (Exception exp)
{
throw (exp);
}
}
}

Step 9: Create a gridview and update form in UI page (Here Default.aspx).
Default.aspx


        
            
                Full Name :
            
            
                
            
        
        
            
                Nick Name :
            
            
                
            
        

        
            
                Designation :
            
            
                
            
        
    

    

        
    

    

    
        
        
            
            
            
            
                
                
                    ' />
                    ' OnClick="btnEdit_Click">
                            
                
            
            
                
                
                    ' OnClick="btnDelete_Click">

Defult.aspx.cs

/// Author : Md. Mahedee Hasan
/// Purpose : Code behind of Default.aspx page
/// Creation Date : 21/04/2012
/// ==================================================================================================
/// || Modification History ||
/// -------------------------------------------------------------------------------------------------
/// Sl No. Date: Author: Ver: Area of Change:
///
/// **************************************************************************************************

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page
{

protected void Page_Load(object sender, EventArgs e)
{

if (!Page.IsPostBack)
{
Load_gvEmpInfo();
}
}

///
/// Binding gridview gvEmpInfo
///

private void Load_gvEmpInfo()
{
EmployeeInfoBLL objEmployeeInfoBLL = new EmployeeInfoBLL();
this.gvEmpInfo.DataSource = objEmployeeInfoBLL.GetEmployeeInfoAll();
this.gvEmpInfo.DataBind();
}

protected void btnEdit_Click(object sender, EventArgs e)
{

this.btnSave.Text = "Edit";

LinkButton btnEdit = sender as LinkButton;

//Identify the clicked row
int rowIndex = Convert.ToInt32(btnEdit.Attributes["RowIndex"]);

GridViewRow gvRow = this.gvEmpInfo.Rows[rowIndex];

//Identify the hidden filed value of clicked row
int emp_gid = Convert.ToInt32(((HiddenField)gvRow.FindControl("hidemp_gid")).Value);

this.txtEmpFullNm.Text = gvRow.Cells[0].Text;
this.txtEmpNickNm.Text = gvRow.Cells[1].Text;
this.txtDesignation.Text = gvRow.Cells[2].Text;

this.hf_emp_gid.Value = emp_gid.ToString();

}

protected void btnDelete_Click(object sender, EventArgs e)
{
LinkButton btnDelete = sender as LinkButton;

//Identify the clicked row
int rowIndex = Convert.ToInt32(btnDelete.Attributes["RowIndex"]);

GridViewRow gvRow = this.gvEmpInfo.Rows[rowIndex];

//Identify the hidden filed value of clicked row
int emp_gid = Convert.ToInt32(((HiddenField)gvRow.FindControl("hidemp_gid")).Value);

string msg = String.Empty;

try
{
EmployeeInfoBLL objEmployeeInfoBLL = new EmployeeInfoBLL();
msg = objEmployeeInfoBLL.RemoveEmployeeInfo(emp_gid);
Load_gvEmpInfo();
ClearForm();
}
catch (Exception exp)
{
msg = exp.Message;
}

}

protected void btnSave_Click(object sender, EventArgs e)
{
String msg = String.Empty;
Button btnSave = sender as Button;

EmployeeInfoBLL objEmployeeInfoBLL = new EmployeeInfoBLL();
EmployeeInfo objEmployeeInfo = new EmployeeInfo();
objEmployeeInfo.EmpFullNm = this.txtEmpFullNm.Text;
objEmployeeInfo.EmpNickNm = this.txtEmpNickNm.Text;
objEmployeeInfo.EmpDesignation = this.txtDesignation.Text;

try
{
if (btnSave.Text == "Edit")
{
objEmployeeInfo.EmpGid = Convert.ToInt32(this.hf_emp_gid.Value);
msg = objEmployeeInfoBLL.EditEmployeeInfo(objEmployeeInfo);
this.btnSave.Text = "Save";
}
else
{
msg = objEmployeeInfoBLL.SaveEmployeeInfo(objEmployeeInfo);
}

Load_gvEmpInfo();
ClearForm();
}
catch (Exception exp)
{
msg = exp.Message;
}

}

///
/// Clear form
///

private void ClearForm()
{
this.txtEmpFullNm.Text = "";
this.txtEmpNickNm.Text = "";
this.txtDesignation.Text = "";
}
}

Yes! You have done this. Now you will see the following form where you can insert update and delete employee information.