Asp.net web service return json

Question

I am using below code for my web service. I want return value in json. but this code return value in XML format only.

 

[WebMethod]

[ScriptMethod(UseHttpGet = true, ResponseFormat = ResponseFormat.Json)]

public bool login(string uname, string pwd)

{

//SqlConnection con = new SqlConnection();

//SqlCommand cmd = new SqlCommand();

//con.ConnectionString = ConfigurationManager.ConnectionStrings["cn"].ConnectionString;

//SqlDataAdapter da = new SqlDataAdapter("select * from UserList where UserName ='" + uname + "' and password='" + pwd + "' ", con);

//DataSet ds = new DataSet();

//da.Fill(ds);

//return ds;

SqlConnection con = new SqlConnection();

SqlCommand cmd = new SqlCommand();

con.ConnectionString = ConfigurationManager.ConnectionStrings["cn"].ConnectionString;

if (con.State == ConnectionState.Closed)

{

con.Open();

}

cmd.CommandText = "select * from UserList where UserName=@username and Password=@pwd";

cmd.Connection = con;

cmd.Parameters.Add("@username", SqlDbType.VarChar, 50).Value = uname;

cmd.Parameters.Add("@pwd", SqlDbType.VarChar, 50).Value = pwd;

SqlDataReader dr = cmd.ExecuteReader();

if (dr.Read() == true)

{

return true;

}

else

{

return false;

}

con.Close();

}