Government Exams,Banks Preparation, Railway Exams and others: WEB SERVICES ...... CREATION & USE OF WEB SERVICES

What is Web Service?

Web Service is an application that is designed to interact directly with other applications over the internet. In simple sense, Web Services are means for interacting with objects over the Internet. The Web serivce consumers are able to invoke method calls on remote objects by using SOAP and HTTP over the Web. WebService is language independent and Web Services communicate by using standard web protocols and data formats, such as

• HTTP

• XML

• SOAP

Advantages of Web Service

Web Service messages are formatted as XML, a standard way for communication between two incompatible system. And this message is sent via HTTP, so that they can reach to any machine on the internet without being blocked by firewall.

Examples for Web Service

Weather Reporting: You can use Weather Reporting web service to display weather information in your personal website.

Stock Quote: You can display latest update of Share market with Stock Quote on your web site.

News Headline: You can display latest news update by using News Headline Web Service in your website.

Creation of web services :

Open visual studio ---> Select File ---> New ---> Web Site ---> select ASP.NET Web Service

Now open your Service.cs file in web service website to write the code to get the user details from database

Before writing the WebMethod in Service.cs first add following namespaces

using System.Xml;

using System.Configuration;

using System.Data;

using System.Data.SqlClient;

After adding namespaces write the following method GetUserDetails in Service.cs page

[WebMethod]

public XmlElement GetUserDetails(string userName)

{

SqlConnection con = newSqlConnection(ConfigurationManager.ConnectionStrings["dbconnection"].ToString());

con.Open();

SqlCommand cmd = new SqlCommand("select * from EXPENSEwhere UserName like @userName+'%'", con);

cmd.Parameters.AddWithValue("@userName", userName);

cmd.ExecuteNonQuery();

SqlDataAdapter da = new SqlDataAdapter(cmd);

// Create an instance of DataSet.

DataSet ds = new DataSet();

da.Fill(ds);

con.Close();

// Return the DataSet as an XmlElement.

XmlDataDocument xmldata = new XmlDataDocument(ds);

XmlElement xmlElement = xmldata.DocumentElement;

return xmlElement;

}

Here we need to remember one point that is adding [WebMethod] before method definition because we need to access web method pulically otherwise it’s not possible to access method publically. If you observe above code I converted dataset to XmlElement t because sometimes we will get error likereturn type dataset invalid type it must be either an IListSource, IEnumerable, or IDataSourceto avoid this error I converted dataset to XmlElement.

Here we need to set the database connection in web.config because here I am getting database connection from web.config

</connectionStrings>

Now run your web service it would be like this

Our web service is working fine now we need to know how we can use webservice in our application? Before to know about using web service in application first Deploy your webservice application in your local system if you want to know how to deploy application in your local system check this link deploy application in local system

How to Use Web service in web application?

By using this webservice we can get the user details based on username. For that first create one new web application

Open visual studio ---> Select File ---> New ---> Web Site ---> select ASP.NET Web Site

After creation of new website right click on solution explorer and choose “Add web reference” that would be like this

Now click on Add Reference button web service will add successfully. Now open your Default.aspx page and design like this

<title>Getting Data from WebService</title>

</head>

<body>

<div>

<table>

<tr>

<td>

<b>Enter UserName:</b>

</td>

<td>

<asp:TextBox ID="txtUserName" runat="server"></asp:TextBox>

</td>

<td>

<asp:Button ID="btnSubmit" runat="server" Text="Submit" onclick="btnSubmit_Click" />

</td>

</tr>

</table>

</div>

<div>

<asp:GridView ID="gvUserDetails" runat="server" EmptyDataText="No Record Found">

</asp:GridView>

</div>

</form>

</body>

</html>

Now in code behind add following namespaces

using System.Data; using System.Xml;

After adding namespaces write the following code in code behind

protected void Page_Load(object sender, EventArgs e)

{

if(!IsPostBack)

{

BindUserDetails("");

}

protected void BindUserDetails(string userName)

{

localhost.Service objUserDetails = new localhost.Service();

DataSet dsresult = new DataSet();

XmlElement exelement = objUserDetails.GetUserDetails(userName);

if(exelement!=null)

{

XmlNodeReader nodereader = new XmlNodeReader(exelement);

dsresult.ReadXml(nodereader, XmlReadMode.Auto);

gvUserDetails.DataSource = dsresult;

gvUserDetails.DataBind();

}

else

{

gvUserDetails.DataSource = null;

gvUserDetails.DataBind();

}

protected void btnSubmit_Click(object sender, EventArgs e)

{

BindUserDetails(txtUserName.Text);

}

WEB SERVICES ...... CREATION & USE OF WEB SERVICES

What is Web Service?

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