Ajax调用Web服务

Question

I'm trying to make a call using ajax to the web service to verify if a userame and password are correct. I am just returning pass or fail in xml. In my asmx page, I am getting an error "an object is required for the non static field , method, or property 'system.web.ui.page.request.get" Also, my xmlhttp.open URL, Am I doing it right ? Does anybody has a suggestion on how to solve this? This is my first post, please let me know if I have asked the question wrong or provided insufficient information. Thank you.

[WebMethod]
    public static string Auth() {
        String strConnString = ConfigurationManager.ConnectionStrings["ConStr"].ConnectionString;
        string str = null;
        SqlCommand com;
        string query = String.Format("select COUNT(TeacherID) from USERS where User= '{0}' and Password='{1}'", Page.Request.QueryString["username"], Page.Request.QueryString["password"]);
        object obj = null;
        SqlConnection con = new SqlConnection(strConnString);
        con.Open();
        com = new SqlCommand(query, con);
        obj = com.ExecuteScalar();
        con.Close();
        Page.Response.Write(obj);
    }



 function getResult() {

        var xmlhttp = new XMLHttpRequest();
        xmlhttp.onreadystatechange = function () {
            if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
                document.getElementById("lblMessage").innerHTML = xmlhttp.responseText;
            }
        }
        xmlhttp.open("GET", "authenticate.asmx.cs?username=" + document.getElementById("txtUserName").value + "&password=" + document.getElementById("txtPassword").value, true);
        xmlhttp.send();

    }

Answer 1

"an object is required for the non static field , method, or property 'system.web.ui.page.request.get"-- this was the actual problem for the webservice. Solved with putting the following code

HttpContext.Current.Request.QueryString["username"],   

HttpContext.Current.Request.QueryString["password"]);

instead of the above posted lines by the user which missed the prefixes.

HttpContext.Current.

The full code is the following:

[WebMethod]
public static string Auth() {
    String strConnString = ConfigurationManager.ConnectionStrings["ConStr"].ConnectionString;
    string str = null;
    SqlCommand com;
    string query = String.Format("select COUNT(TeacherID) from USERS where User= '{0}' and Password='{1}'",  HttpContext.Current.Request.QueryString["username"],  HttpContext.Current.Request.QueryString["password"]);
    object obj = null;
    SqlConnection con = new SqlConnection(strConnString);
    con.Open();
    com = new SqlCommand(query, con);
    obj = com.ExecuteScalar();
    con.Close();
    Page.Response.Write(obj);
}