如何从JS调用服务器端方法

Question

I've read many questions, forums, blogs, tried many things and I just can't seems to make it work.

I've tried using PageMethods.MyMethod() and that didn't work. Made sure my ScriptManager had EnablePageMethods ="true" and still nothing. I have a breakpoint on the server side and it never hits. Tried using ajax and still nothing

I'm 1st trying to understand how to make it work to then implemented on my program.

This is what I've tried so far:

Server-side:

[System.Web.Services.WebMethod]
    public static void SomeMethod(string subject, string body, string recipients, string CurrentUserId)
    {
        MessageBox.Show("In c#");
    }

JS:

function SomeFuntion()
{
        debugger; alert("Before web service");

        //PageMethods.CreateDraft(var1, var2, var3, var4);

        $.ajax
            (
                {
                    type: "POST",
                    url: "NewMessage.aspx/SomeMethod",
                    data: "{subject:'" + var1+ "', body:'" + var2+ "', recipients:'" + var3
                        + "', CurrentUserId:'" + var4+ "'}",
                    contentType: "application/json; charset=utf-8",
                    dataType: "json",
                    success:
                        function()
                        {
                            alert("In ajax");
                        }
                }
            );
}

As you can see, I tried PageMethods and it didn't work. I know the function runs cause I see the alert message. By the way, the function is being called when the onclick event is fired of on a button. I don't get any errors and neither does it hit the break point on the MessageBox . This is new to me so any explanation would be very helpful too.

Answer 1

Check for errors from the server:

function SomeFuntion()
{

    $.ajax({
            type: "POST",
            url: "NewMessage.aspx/CreateDraft",
            data: "{subject:'" + var1+ "', body:'" + var2+ "', recipients:'" + var3+ "', CurrentUserId:'" + var4+ "'}",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            beforeSend:function () 
            {
                 alert("about to send request");
            },
            success: function()
            {
                        alert("In ajax");
            },
            error: function(xhr, status, error) 
            {
                   var err = eval("(" + xhr.responseText + ")");
                   alert(err.Message);
            }
        );
}

more additions Since you are telling me that you are getting a "The HTTP verb POST used to access path '...' is not allowed" you might need configuration to enable .NET web service for http POST requests.

I have dropped .NET few years ago and therefore I have no direct experience but from what I could find in other sites you might need configuration at the server level such:

<system.web>
   <webServices>
     <protocols>
       <add name="HttpPost"/>
     </protocols>
   </webServices>
 </system.web>

Or directives above your method such

[ScriptMethod(UseHttpPost = true)]
public string SomeMethod()
{
    ....
}

Answer 2

I managed to figure it out with the help of a friend, I would post my answer but I believe it's quite long and complicated. I understood most of the things he did but I still didn't believe how it worked. It was pretty much almost the same thing I did but he made the JS in a separate file and set that file like a base JS. Called the web service there and from my JS he called that function that calls the web service. And it worked lol