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
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.
In summary you can any use any web service which is available to use. You can make your own web service and let others use it. Example you can make Free SMS Sending Service with footer with your advertisement, so whosoever use this service indirectly advertise your company... You can apply your ideas in N no. of ways to take advantage of it.
Frequently used word with web services
What is SOAP?
SOAP (simple object access protocol) is a remote function calls that invokes method and execute them on Remote machine and translate the object communication into XML format. In short, SOAP are way by which method calls are translate into XML format and sent via HTTP.
What is WSDL?
WSDL stands for Web Service Description Language, a standard by which a web service can tell clients what messages it accepts and which results it will return.
WSDL contains every detail regarding using web service and Method and Properties provided by web service and URLs from which those methods can be accessed and Data Types used.
What is UDDI?
UDDI allows you to find web services by connecting to a directory.
What is Discovery or .Disco Files?
Discovery files are used to group common services together on a web server. Discovery files .Disco and .VsDisco are XML based files that contains link in the form of URLs to resources that provides discovery information for a web service. Disco File contains URL for the WSDL, URL for the documentation and URL to which SOAP messages should be sent.
Before start creating web service first create one table in your database and give name UserInformationin my code I am using same name and enter some dummy data for our testing purpose
Column Name
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Data Type
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Allow Nulls
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UserId
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Int(Set Identity=true)
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No
|
UserName
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Varchar(50)
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Yes
|
FirstName
|
Varchar(50)
|
Yes
|
LastName
|
Varchar(50)
|
Yes
|
Location
|
Varchar(50)
|
Yes
|
Now we will see how to create new web service application in asp.net
Open visual studio ---> Select File ---> New ---> Web Site ---> select ASP.NET Web Service
Now our new web service ready our webservice website like this
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
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using System.Xml;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
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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 UserInformation where 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;
}
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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 like return type dataset invalid type it must be either an IListSource, IEnumerable, or IDataSource to 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
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<connectionStrings>
<add name="dbconnection" connectionString="Data Source=SureshDasari;Integrated Security=true;Initial Catalog=MySampleDB"/>
</connectionStrings>
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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
After select Add Web reference option one window will open like this
Now enter your locally deployed web service link and click Go button after that your web service will found and window will looks like this
Now click on Add Reference button web service will add successfully. Now open your Default.aspx page and design like this
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Getting Data from WebService</title>
</head>
<body>
<form id="form1" runat="server">
<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">
<RowStyle BackColor="#EFF3FB" />
<FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
<PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
<HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
<AlternatingRowStyle BackColor="White" />
</asp:GridView>
</div>
</form>
</body>
</html>
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Now in code behind add following namespaces
using System.Data;
using System.Xml;
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|
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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);
}
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Now run your application and check output
