barcode library c# WEB SERVICES IN WEB APPLICATIONS in Font

Creating Code-39 in Font WEB SERVICES IN WEB APPLICATIONS

CHAPTER 9 WEB SERVICES IN WEB APPLICATIONS
Generate Code 39 In None
Using Barcode generator for Font Control to generate, create Code 39 Full ASCII image in Font applications.
www.OnBarcode.com
UCC-128 Generation In None
Using Barcode creator for Font Control to generate, create UCC.EAN - 128 image in Font applications.
www.OnBarcode.com
1. In the Partners.asmx.vb file, locate the GetContactRequests() method, and update it to match the following code, causing an XML document, rather than a DataSet, to be returned: Public Function GetContactRequests(ByVal login As String, _ ByVal password As String) As XmlDocument cnFriends.Open() Try cmContacts.Parameters("@Login").Value = login cmContacts.Parameters("@Password").Value = password Dim contacts As New DataSet("Contacts") Dim ad As New SqlDataAdapter(cmContacts) ad.Fill(contacts, "Contact") Return New XmlDataDocument(contacts) Finally cnFriends.Close() End Try End Function 2. The XmlDataDocument and XmlDocument classes you re using here come from the System.Xml namespace, so let s import the corresponding namespace: Imports System.Xml 3. Because you ve altered the signature of the web method, it no longer accepts or returns the same number or type of parameters that it did previously. As the web reference could technically be a link to functionality on the other side of the world that is unavailable for long periods of time, .NET doesn t automatically update the details of these references; as far as the test application is concerned, you haven t changed the web service. Before synchronizing it with the latest version of the service, you must first rebuild the project. Select Build Rebuild Solution to do this. 4. Switch to the Acudei project. Right-click the FriendsService entry under Web References in the Solution Explorer for the project, and then select the Update Web Reference option. 5. Open the Default.aspx form and import the following namespace, so that you can use the XmlNode and XmlNodeReader classes in the next step: Imports System.Xml 6. With the references updated, you can tweak the code to make use of the amended method. Within the btnRefresh_Click() method in the Default.aspx form, modify the following code: Private Sub btnRefresh_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles btnRefresh.Click Dim friends = New Acudei.FriendsService.Partners
Barcode Printer In None
Using Barcode creator for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Making Data Matrix 2d Barcode In None
Using Barcode drawer for Font Control to generate, create ECC200 image in Font applications.
www.OnBarcode.com
CHAPTER 9 WEB SERVICES IN WEB APPLICATIONS
Drawing PDF 417 In None
Using Barcode printer for Font Control to generate, create PDF 417 image in Font applications.
www.OnBarcode.com
Code-128 Printer In None
Using Barcode generator for Font Control to generate, create Code 128B image in Font applications.
www.OnBarcode.com
' We now retrieve a bare XML representation Dim contacts As XmlNode = friends.GetContactRequests( _ txtLogin.Text, txtPassword.Text) Dim ds As New DataSet ' Read from the node ds.ReadXml(New XmlNodeReader(contacts)) grdContacts.DataSource = ds grdContacts.DataBind() End Sub This will create a new DataSet, and then read the information into it from the XML that is now returned from your web service. Note that the proxy generated a method returning an XmlNode instance, which is the base class for the XmlDocument. This is due to the very nature of SOAP: the whole message is an XML document, so the contents of the body can be only a node inside it, instead of a separate document. Once the DataSet is populated, you data bind the DataGrid control with this source, just as before. 7. If you like, you can start the project and test this functionality. What is more interesting, though, is testing the GetContactRequests() method in a browser. To do this, type http://localhost/FriendsReunion/Services/Partners.asmx op=GetContactRequests into the browser, and type in the apress login and password as usual. The window showing the returned XML will look similar to Figure 9-13. If you compare this with Figure 9-6, you ll see that there is far less data present.
Generate Barcode In None
Using Barcode generation for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
MSI Plessey Generation In None
Using Barcode maker for Font Control to generate, create MSI Plessey image in Font applications.
www.OnBarcode.com
How It Works Usually, retrieving information from the database into the web application isn t an excessively expensive operation, because the connection to the database server from the web server is probably of high bandwidth. However, returning that data from the web server to the client can be a major bottleneck that causes poor performance in applications, because it s usually a low-bandwidth connection, such as a dial-up connection or wide area network (WAN) access. So, you must ensure that you send only the necessary information, and in the most compact format possible. We have already discussed how the DataSet serializes to a heavy XML representation. To solve this problem, you can take this DataSet and serialize it in a more lightweight structure. In this case, you simply contained data as a clean XML document, within the business logic of the service. You can then return this simpler data instead, resulting in a far lower data overhead. XmlDataDocument is an XmlDocument-derived class that presents a DataSet as an XmlDocument, hiding all the non-XML relevant information, such as row IDs and type. It simply wraps the DataSet, and you can directly return it from the web service: Dim contacts As New DataSet("Contacts") Dim ad As New SqlDataAdapter(cmContacts) ad.Fill(contacts, "Contact") Return New XmlDataDocument(contacts)
Drawing Code 39 Extended In None
Using Barcode creator for Software Control to generate, create Code-39 image in Software applications.
www.OnBarcode.com
Painting Code-39 In None
Using Barcode printer for Excel Control to generate, create USS Code 39 image in Office Excel applications.
www.OnBarcode.com
Barcode Maker In VB.NET
Using Barcode creation for VS .NET Control to generate, create Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Create Barcode In None
Using Barcode generator for Software Control to generate, create Barcode image in Software applications.
www.OnBarcode.com
Drawing Barcode In None
Using Barcode printer for Word Control to generate, create Barcode image in Microsoft Word applications.
www.OnBarcode.com
Create PDF-417 2d Barcode In None
Using Barcode generator for Online Control to generate, create PDF417 image in Online applications.
www.OnBarcode.com
PDF-417 2d Barcode Drawer In .NET Framework
Using Barcode encoder for ASP.NET Control to generate, create PDF-417 2d barcode image in ASP.NET applications.
www.OnBarcode.com
Generate EAN 128 In Visual Basic .NET
Using Barcode creator for VS .NET Control to generate, create UCC-128 image in VS .NET applications.
www.OnBarcode.com
Read Barcode In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Making Code 3 Of 9 In Java
Using Barcode drawer for Java Control to generate, create Code 39 Full ASCII image in Java applications.
www.OnBarcode.com
Draw UCC.EAN - 128 In Java
Using Barcode maker for Java Control to generate, create GS1 128 image in Java applications.
www.OnBarcode.com
Decode QR-Code In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.