Microsoft KB Archive/320634

= HOW TO: Update Server Data Through a Web Service by Using ADO.NET and Visual J# .NET =

Article ID: 320634

Article Last Modified on 9/3/2003

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APPLIES TO


 * Microsoft ADO.NET 1.1
 * Microsoft ADO.NET 1.0
 * Microsoft ASP.NET 1.1
 * Microsoft ASP.NET 1.0
 * Microsoft Visual J# .NET 2003 Standard Edition
 * Microsoft Visual J# .NET 2003 Standard Edition

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This article was previously published under Q320634



For a Microsoft Visual Basic .NET version of this article, see 308056.

For a Microsoft Visual C# .NET version of this article, see 310143.

This article refers to the following Microsoft .NET Framework Class Library namespace:
 * System.Data.SqlClient

IN THIS TASK
SUMMARY
 * Requirements
 * Create the Web Service
 * Test the Web Service
 * Create the Client Application
 * Test the Client Application

REFERENCES



SUMMARY
This step-by-step article demonstrates how to use an Web service to receive and to update data from a database by using a DataSet object. This article also demonstrates how to reference the Web service in a client application and how to display the returned DataSet in a DataGrid control so that you can update that data and send the updates back to the server.

NOTE: You can only use the method in this article for single-table updates.

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Requirements
The following list outlines the recommended hardware, software, network infrastructure, and service packs that are required:
 * Microsoft Windows 2000 Professional, Windows 2000 Server, Windows 2000 Advanced Server, or Windows NT 4.0 Server
 * Microsoft Visual Studio .NET
 * Microsoft Visual J# .NET

This article assumes that you are familiar with the following topics:
 * Visual Studio .NET
 * ADO.NET fundamentals and syntax
 * ASP.NET fundamentals and syntax

The code samples in this article use http://localhost as the Web server. Additionally, the code samples use the Northwind database. The Northwind database is included with Microsoft SQL Server.

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Create the Web Service
 Start Visual Studio .NET. Follow these steps to create a new Visual J# ASP.NET Web Service project:  On the File menu, point to New, and then click Project. In the New Project dialog box, click Visual J# Projects under Project Types, and then click ASP.NET Web Service under Templates. In the Location box, type the URL for your server and the project name, jsUpdateData (for example, http://localhost/jsUpdateData). The http://localhost portion of the URL runs the Web service on your local Web server. Click OK.  On the Service1.asmx.jsl[Design] tab, right-click the page, and then click View Code to switch to Code view. The Code window for the Web service appears.</li>  At the top of the Code window, after the package statement, add the following import statement: //Use data access objects from the SqlClient namespace. import System.Data.SqlClient.*; </li>  After the following code public Service1 {           //CODEGEN: This call is required by the ASP.NET Web Services Designer InitializeComponent; } add the following code: /** @attribute WebMethod */ public DataSet GetCustomers {       SqlConnection con = new SqlConnection(&quot;server=servername;uid=login;pwd=password;database=northwind&quot;); SqlDataAdapter daCust = new SqlDataAdapter(&quot;Select * From Customers&quot;, con); DataSet ds = new DataSet; daCust.Fill(ds, &quot;Cust&quot;); return ds; }

/** @attribute WebMethod */ public DataSet UpdateCustomers(DataSet ds) {       SqlConnection con = new SqlConnection(&quot;server=servername;uid=login;pwd=password;database=northwind&quot;); SqlDataAdapter daCust = new SqlDataAdapter(&quot;Select * From Customers&quot;, con); SqlCommandBuilder cbCust = new SqlCommandBuilder(daCust); daCust.Update(ds, &quot;Cust&quot;); return ds; }                    </li> Modify the SqlConnection string to properly connect to the computer that is running SQL Server.</li></ol>

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Test the Web Service

 * 1) Press F5 to compile and to run the Web service. A Web page is displayed in which you can interact with the Web service from within Microsoft Internet Explorer.

Note that the URL of the returned page is http://localhost/jsUpdateData/Service1.asmx.
 * 1) On the Service1 Web page, click GetCustomers. A Web page is displayed that includes details about the GetCustomers Web method.
 * 2) Close the Web pages.

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Create the Client Application
 In Visual Studio .NET, create a new Visual J# Windows Application project. By default, Form1 is added to the project.</li> Add two Button controls and one DataGrid control to Form1. By default, Button1, Button2, and DataGrid1 are added to the project.</li> Change the Text property of Button1 to Load, and then change the Text property of Button2 to Save .</li> On the Project menu, click Add Web Reference. Type the URL for your Web service (for example, type http://localhost/jsUpdateData/Service1.asmx ), press ENTER, and then click Add Reference. The entry for the newly added Web reference appears in Solution Explorer.</li>  In the Visual J# project, double-click Load to open the Code window for Load. Add the following code to the Load_Click event procedure: localhost.Service1 MyService = new localhost.Service1; dataGrid1.set_DataSource(MyService.GetCustomers); dataGrid1.set_DataMember(&quot;Cust&quot;); </li> Switch to Form view.</li>  Double-click Save to open the Code window for Save. Add the following code into the Save_Click event procedure: localhost.Service1 MyService = new localhost.Service1; DataSet ds = (DataSet) dataGrid1.get_DataSource; DataSet dsChanges = ds.GetChanges; if (dsChanges != null) {          ds.Merge(MyService.UpdateCustomers(dsChanges), true); }                    </li></ol>

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Test the Client Application

 * 1) Press F5 to compile and to run the client application.
 * 2) Notice that initially DataGrid1 is empty. Click Load. Note that DataGrid1 now displays the Customer records.
 * 3) In DataGrid1, modify some of the data, and then click Save.

NOTE: Do not change the key field. If you change the key field, you receive an error message, which states that you are breaking referential integrity on the server.

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