Web services in asp.net
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This document provides instructions for creating a web service in ASP.NET (VB code) with three methods - one each for adding and subtracting two numbers, and another for connecting to a SQL database. It describes creating a web service project, adding methods to perform basic math operations, testing the service, consuming it in a web page, and includes sample code for connecting the web service to a SQL database.
Web services in asp.net
- 1. Web Services in Asp.net (VB Code) 1. Run Visual Web Developer / Visual Studio (I am using Visual Studio 2013) 2. Click on New project. 3. From the left-side pane, choose Templates → Visual Basic → Web 4. Choose Asp.net web application from the central window. Give some file name and choose your convenient drive and a folder. 5. Click OK to proceed. 6. Choose Empty from ‘Select a Template’ screen. Stage 1: Creating Web Service 1. Right Click on Project (from the Solution Explorer). Select Add→New Item → Web Service (ASMX)
- 2. 2. Give some name for this webservice (or retain the default name suggested by your system). I have retained the default name ie. WebService1.asmx. Click on Add button. The system switch over to the screen with the following codes. 3. Now, concentrate on the section starting with the line <WebMethod()>_ 4. Here you can write your own codes. Now, let us try ourselves. 5. Let us add two methods in this section to add and subtract two numbers. a. First remove the lines Public Function ….. End Function b. Add the following lines as shown below (I have added two methods – add and subtract). See the code below.
- 3. 6. Now, you can check the above codes for any errors. For this purpose, click on Build → Build Solution. 7. You can see message is 1 succeeded, 0 failed ….. This shows that the new codes added is OK. 8. You can also run your web service code in a browser. For this, right click on the screen and choose ‘Run to Cursor’. The program runs in your default browser. 9. Notice our two methods (functions) namely, add and subtract are appearing on the screen. Click on them and supply two numeric values to test whether these functions are working properly or not. 10. That’s it. We have created a web service with two functions – one for addition of two numbers and another for subtracting two numbers. Stage 2: Importing this webservice to our website Now, let us see how to import the Webservice created in the above to our website. 1. Stop the debugging of the above webservice, if any by pressing Shift+F5 or clicking on the stop debugging button as shown below
- 4. 2. Right click on the Project (Visible in the Solution Explorer window) → Add → Service Reference. 3. Click on the Discover button 4. You can see WebService1.asmx appears on the Services window. 5. Expand all the nodes to view Add and Subtract functions in the Operations Window.
- 5. 6. Press Ok to save. Stage 3: Consuming the WebService from a web page Now, let us see, how to consume (or use in a web page) 1. Right click on Project → Add → New Item → Web Form 2. Change to design mode. 3. Add Two Text Boxes, Two Labels and a Button as shown below. 4. Double click on the Button. Add codes for the Button1 click event. 5. Save the webpage. Go back to design mode. View your webpage in a browser (ie. Right click on your webpage and select View in Browser option). Note: When you are in debug mode, you cannot view the webpage in a browser. For this purpose, close the debug mode by pressing Shift+F5 buttons) That’s it. You have created a webservice and a webpage which consume it. I have used Visual Basic codes for the above. It can also be developed using C# with few modifications. Webservices with Database Connectivity: I have given below code required to connect a back-end database (in this case, I have used MS SQL Server) from a web services.
- 6. Imports System.Web Imports System.Web.Services Imports System.Web.Services.Protocols Imports System.Data.SqlClient ' To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. ' <System.Web.Script.Services.ScriptService()> _ <WebService(Namespace:="http://tempuri.org/")> _ <WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _ <Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _ Public Class WebService Inherits System.Web.Services.WebService <WebMethod()> _ Public Function HelloWorld() As String Return "Hello World" End Function <WebMethod()> _ Public Function connect(vcode as string ) As String Dim connection As SqlConnection Dim command1 As SqlCommand Dim dr1 As SqlDataReader Dim sql1, sql2 As String connection = New SqlConnection("Data Source=xxxx;Initial Catalog=xxxx;User ID=xxxx;Password=xxxx") connection.Open()
- 7. Dim vcode as As String sql1 = "select VendorName from vendorMaster where vendorCode='" + vcode + "'" command1 = New SqlCommand(sql1, connection) dr1 = command1.ExecuteReader While dr1.Read Return (dr1("VendorName").ToString) End While End Function End Class -------------------------------- Happy coding. - BK Dharmaraju, Bangalore, India. [email protected] 15th Apr 2020.