ASP.NET: Web Service or WCF for simple ajax call?

I just w开发者_JAVA百科ant to simply call a method on my web service via ajax and have it return a value.

Should I use "WCF Service" , "AJAX-Enabled WCF Service" , or "Web Service"

Which is the easiest?

Use a generic HTTP handler instead. They are simpler to code.

You should use Ajax-Enabled WCF service. I don't remember the name exactly but it should be marked with an attribute to be accessible from JS.

You should never use the "Web Service" template unless you're maintaining existing code and can't change.

If you are just calling a single method use ScriptMethod

You can code it inline with the page that it is used on. http://www.asp.net/ajax/tutorials/understanding-asp-net-ajax-web-services

Using the ScriptMethod Attribute

The ScriptService attribute is the only ASP.NET AJAX attribute that has to be defined in a .NET Web Service in order for it to be used by ASP.NET AJAX pages. However, another attribute named ScriptMethod can also be applied directly to Web Methods in a service. ScriptMethod defines three properties including UseHttpGet, ResponseFormat and XmlSerializeString. Changing the values of these properties can be useful in cases where the type of request accepted by a Web Method needs to be changed to GET, when a Web Method needs to return raw XML data in the form of an XmlDocument or XmlElement object or when data returned from a service should always be serialized as XML instead of JSON.

The UseHttpGet property can be used when a Web Method should accept GET requests as opposed to POST requests. Requests are sent using a URL with Web Method input parameters converted to QueryString parameters. The UseHttpGet property defaults to false and should only be set to true when operations are known to be safe and when sensitive data is not passed to a Web Service. Listing 6 shows an example of using the ScriptMethod attribute with the UseHttpGet property.

If those are your only options, I've found the AJAX-Enabled WCF Service to be the simplest to work with. It's still WCF, but it templates out for you the proper web.config setup and ditches the interface that the plain "WCF Service" template gives you. It seems to be the closest thing in the whole WCF mess to the old ASMX-style as far as being dirt simple to get going.

Just as another alternative, if you happen to be able to use ASP.NET MVC in your webforms project and just need this for an ajax call, you could skip the web service hoopla altogether and create a simple JSON result for your AJAX call like so:

// put this method in a controller
public JsonResult AjaxJsonTest(string who) {
   var result = new {
      Success = true,
      Message="Hello, " + (who ?? "world!")
   }; 
   return Json(result, JsonRequestBehavior.AllowGet);
}

And then you can call it from jQuery like this:

<script language="javascript" type="text/javascript">
function AjaxTestClick() {
    $.ajax({
        type: "POST",
        url: '<%: Url.Action("AjaxJsonTest", "Test") %>',
        data: { who: 'whomever' },
        success: function (resultData) {
            if (resultData.Success) {
                alert(resultData.Message);
            }
            else {
                alert('Ajax call failed.');
            }
        }
    });
}
</script>

Tons of options - pick what suits your situation best.