Using WCF with AJAX to Convert ��F to °C in C#

This tutorial shows you how to easily create and consume a WCF service into an AJAX Web Application using ASP.NET and C#

In this tutorial, we will show you an extremely easy way to implement WCF into a Web Page using AJAX. We use Visual Studio 2008 and ASP.NET 3.5 for this demonstration. The Service will allow us to submit a °F value to it, and it will convert that to °C and return that value back to the Web Page.

To begin, we will create a regular ASP.NET Web Application in Visual Studio, then we will right-click the Project in Solution Explorer and choose to Add New Item.. AJAX-enabled WCF Service. Name it FtoC, and wrap the class in a namespace, like so:

using System; using System.Linq; using System.Runtime.Serialization; using System.ServiceModel; using System.ServiceModel.Activation; using System.ServiceModel.Web; namespace AspNetTutorials.FtoC { [ServiceContract(Namespace = "http://aspnettutorials.com/FtoC")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class FtoC { // Add [WebGet] attribute to use HTTP GET [OperationContract] public void DoWork() { // Add your operation implementation here return; } // Add more operations here and mark them with [OperationContract] } }

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We can keep the same structure, and input our own method:

[ServiceContract(Namespace = "http://aspnettutorials.com/FtoC")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class FtoC { [OperationContract] public static int convertFtoC(int theFahrenheit) { return (theFahrenheit - 30) / 2; } }

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We declare the class as a ServiceContract and the method as an OperationContract, exposing it to the outside world.

Next, to use the Service in our ASPX page, we will make a reference to it:

using AspNetTutorials.FtoC;

Then we declare a ScriptManager on the page to handle our AJAX calls and also an UpdatePanel:

<asp:ScriptManager ID="ScriptManager1" runat="server" /> <asp:UpdatePanel ID="UP1" runat="server"> <ContentTemplate> </ContentTemplate> </asp:UpdatePanel>

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Next, we can add our ASP.NET controls to the page. We will add a textbox, button and literal:

<asp:ScriptManager ID="ScriptManager1" runat="server" /> <asp:UpdatePanel ID="UP1" runat="server"> <ContentTemplate> Convert °F to °C: <asp:TextBox ID="fld_Fahr" runat="server" Columns="3" /><br /> <asp:Button ID="btn_FtoC" runat="server" Text="Convert" OnClick="btn_FtoC_Click" /><br /> <asp:Literal ID="lit_FtoC" runat="server" /> <br /><br /> </ContentTemplate> </asp:UpdatePanel>

Finally, the last piece of our application is to add the logic to our code-behind, which is a very simple call to the WCF Service, like any other:

protected void btn_FtoC_Click(object sender, EventArgs e) { lit_FtoC.Text = FtoC.convertFtoC(Convert.ToInt16(fld_Fahr.Text)).ToString(); }

Now when we run the page, we can instantly get the conversion of Fahrenheit into Celsius.