Error in inserting data with JSON and Ajax - asp.net

Question

I don't know where the problem is, my code looks fine and I tried hard, but getting error all the time.
Here is my code:
Markup:
<link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.1/themes/base/jquery-ui.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.1/jquery-ui.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("#Button1").click(function(){
var Name=document.getElementById('Text1').value
var Class=document.getElementById('Text2').value
var Data=JSON.stringify({Name:Name,Class:Class});
alert(Data);
$.ajax({
type: 'POST',
contentType: "application/json; charset=utf-8",
url: 'Default.aspx/InsertData',
data:Data,
async: false,
success: function (response) {
$('#Text1').val('');
$('#Text2').val('');
},
error: function () {
alert("Error")
}
});
});
});
</script>
ASP.NET AJAX Page Method in code-behind:
[WebMethod]
public string InsertData(string Name, string Class)
{
SqlCommand cmd = new SqlCommand("Insert into employee(EmployeeName,Class) values(#EmpName,#Classs)",con);
cmd.Parameters.AddWithValue("#EmpName", Name);
cmd.Parameters.AddWithValue("#Classs",Class);
cmd.ExecuteNonQuery();
con.Close();
return "True";
}

Answer 1

Try this:
Method must be static if it is in aspx page code behind
[WebMethod]
public static string InsertData(string Name, string Class)
{
SqlCommand cmd = new SqlCommand("Insert into employee(EmployeeName,Class) values(#EmpName,#Classs)",con);
cmd.Parameters.AddWithValue("#EmpName", Name);
cmd.Parameters.AddWithValue("#Classs",Class);
cmd.ExecuteNonQuery();
con.Close();
return "True";
}

Answer 2

You don't need to stringify it.
Without stringifying just pass
"{'Name':'"+Name+"','Class':'"+Class+"'}"
If you want to pass the stringified object it must be as shown below
JSON.stringify({'Name':Name,'Class':Class});
See the Quotes added.
var Data=JSON.stringify({'Name':Name,'Class':Class});
alert(Data);
$.ajax({
type: 'POST',
contentType: "application/json; charset=utf-8",
url: 'Default.aspx/InsertData',
data:Data,
async: false,
success: function (response) {
$('#Text1').val('');
$('#Text2').val('');
},
error: function ()
{ alert("Error") }
});
And in the page back code
[WebMethod]
public string InsertData(myobj getdat)
{
SqlCommand cmd = new SqlCommand("Insert into employee(EmployeeName,Class) values(#EmpName,#Classs)",con);
cmd.Parameters.AddWithValue("#EmpName", getdat.Name);
cmd.Parameters.AddWithValue("#Classs",getdat.Class);
cmd.ExecuteNonQuery();
con.Close();
return "True";
}
public class myobj
{
public string Name {get;set;}
public string Class{get;set;}
}

Answer 3

ASP.NET AJAX Page Methods must be static, change your code to this:
[WebMethod]
public static string InsertData(string Name, string Class)
{
SqlCommand cmd = new SqlCommand("Insert into employee(EmployeeName,Class) values(#EmpName,#Classs)",con);
cmd.Parameters.AddWithValue("#EmpName", Name);
cmd.Parameters.AddWithValue("#Classs",Class);
cmd.ExecuteNonQuery();
con.Close();
return "True";
}
Read Why do ASP.NET AJAX page methods have to be static? for an explanation as to why.