Pass variable from jQuery to WebMethod (Authentication failed)

Question

I create a new WebForms Application in VS2013. I didn't change anything and created a simple page. I want to load this table on client side when user clicks button

<table id="tblHelpRow">
        <thead>
            <tr class="title">
                <th>F2
                </th>
                <th>F3
                </th>
            </tr>
        </thead>
        <tbody id="helpRowBody">         
            <%=MyRow %>  
        </tbody>
    </table>
<asp:LinkButton ID="lnkEdit" runat="server" onclick="fnEdit();" />

This is my script code:

function fnEdit() {
    BindGridView();
};
function BindGridView() {
    rowid = {rowID:2};
        $.ajax({
            type: "POST",
            url: "Default.aspx/GetRow",
            contentType: "application/json; charset=utf-8",
            data: param,
            dataType: "json",
            success: function (data) {
                 alert(data);
            }
        });
}

I have a WebMethod in my code-behind which stores result in the public property. DataSource I store in session, but rowID I need to pass from jquery.

        [WebMethod]
        public static string GetRow(int rowID)
        {
                DataTable dt = (DataTable)HttpContext.Current.Session["SourceData"];
                MyRow = "<tr>" +
                "<td>" + dt.Rows[rowID]["F2"].ToString() + "</td>" +
                "<td>" + dt.Rows[rowID]["F3"].ToString() + "</td>" +
                "</tr>";
            return "done";
    }

But I don't get any result. When I have put the breakpont in success I got "Authentication failed" error and this webmethod wasn't executed. What's the problem? I didn't change ant Authentication settings.

Answer 1

Try removing the ScriptMethod attribute. You are specifying a POST action type but I believe the ScriptMethod forces the request to be a GET by default. Also, I believe your param needs to be a JSON string instead of just an integer:

var param = {rowID:2};
$.ajax({
    type: "POST",
    url: "Default.aspx/GetRow",
    contentType: "application/json; charset=utf-8",
    data: JSON.stringify(param),
    dataType: "json",
    success: function (data) {
         alert(data);
    }
});