I am trying to simply pass some values from Javascript into my codebehind for processing.
I just want to pass a Number and Message to the WebMethod but get different errors based on whatever thing I change.
JS:
function SendMessage() {
var number = document.getElementById("number").value;
var message = document.getElementById("message").value;
var msg = {
    "Number": number,
    "Message": message
};
$.ajax({
    type: "POST",
    url: "Default.aspx/SendMessage",
    data: JSON.stringify(msg),
    contentType: "application/json; charset=utf-8",
    dataType: "json",
    success: function (msg) {
        alert("Message sent");
    },
    error: function (msg) {
        alert("Message call failed");
    }
});
}
In my codebehind I have a WebMethod defined and also a Message class to hold my message
[WebMethod]
public static void SendMessage(string message)
{
    //Create a  TMessage and deserialize to it
}
Message:
public class TMessage
{
    public string Number { get; set; }
    public string Message { get; set; }
}
My understanding is that I am receiving JSON and should deserialize it to a Message type.
However I have a breakpoint in the SendMessage method and it never gets hit, the error being returned is:
Message=Invalid web service call, missing value for parameter: 'message'.
From some playing around earlier, I was able to get the breakpoint hit by changing the parameter from string to object (and some changes to the data: value in the Ajax call), but then it seemed I was receiving a Dictionary and I couldn't cast it to TMessage.
Thanks for any suggestions.