Creating a Web Services Client in Visual Studio
To test our Web Service, we're going to write a simple client in Visual Studio. To get things started, create a new C# Windows application. This can be done by going to File->New->Project and selecting Windows Application. In the Solution Explorer for this project (usually shown on the right), right-click on references and you'll have the option of adding a new Web Reference. Select this and you'll be presented with the screen shown in Figure 18. Here you must specify the location of the WSDL. Building on what we've already done, the address you want to type in is http://localhost:8080/ItemLookupWSDL. Type this in and click on the Go button. Visual Studio should find your OurAmazonItemLookup method we defined earlier in this exercise. Click on the Add Reference button to add it to your project.

Now that we have a reference to our service, we'll need to write some code to go about using it. But first we'll have to set up some GUI elements. In the toolbox (usually shown on the left) drag four label controls onto your form. Name them labelItemID, labelTitle, labelAuthor, and labelManufacter. Next add a text box and name it textBoxItemID. Finally add a button. Your finished layout should look something like Figure 19.

Now that we have our GUI designed, we can write some code to make our call to the OurAmazonIItemLookup method. Copy the code in Listing 3 to the clicked event of your form's button. If you study this code, you'll notice that we're getting a reference to our Web Service and then making a call by passing it the value the user typed in the text box. Finally, we use the result set to assign the text property of the respective label controls. Note: error checking has been omitted for clarity.

The Finished Product
To use our Web Services client simply type in a UPC corresponding to an item that you've already entered in your SQL Anywhere database, click the OK button and through the magic of SQL Anywhere Web Services your title information is returned to the client. The finished product is shown in Figure 20.

Conclusion
Building your own "Amazon-like" ItemLookup Web Services is a piece of cake when you use SQL Anywhere's Sybase Central wizard to create them. Moreover, consuming them in Visual Studio is just as easy. Take a few minutes to familiarize yourself with these powerful development tools and you too will be publishing and consuming Web Services in no time!

References

-  SQL Anywhere Documentation www.ianywhere.com/developer/product_manuals/sqlanywhere.
-  SQL Anywhere Developer Edition http://eshop.sybase.com/eshop/try_buy.
-  Visual C# and Visual Studio IDE http://msdn2.microsoft.com/en-us/vcsharp/aa336807.aspx.
-  Inside SOAP www.xml.com/pub/a/2000/02/09/feature/index.html.