Question

I am working on a code in C#.NET to create a web service that will take in a particular input. It will then connect to the database , where depending on the input provided, the entire result must be fetched from my table and displayed accordingly.

However, I am not that familiar with C#.NET and so I am not able to implement my code properly. can someone please help me

Here is what I have do so far:

       using System;
       using System.Collections;
       using System.ComponentModel;
       using System.Data;
       using System.Linq;
       using System.Web;
       using System.Web.Services;
       using System.Web.Services.Protocols;
       using System.Xml.Linq;
       using System.Data.SqlClient;

  namespace test3
     {
          /// <summary>
      /// Summary description for Service1
       /// </summary>
   [WebService(Namespace = "http://tempuri.org/")]
   [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [ToolboxItem(false)]
  // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
   // [System.Web.Script.Services.ScriptService]
   public class Service1 : System.Web.Services.WebService
   {
      [WebMethod]
        public String GetAttendance(String rollno)
       {
          String result="";


          try
           {
              using (SqlConnection myConnection = new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=student;User ID=sa;Password=123"))
            {

                myConnection.Open();

                using (SqlCommand myCommand = new SqlCommand())
                {

                    myCommand.Connection = myConnection;
                    myCommand.CommandText = "SELECT COUNT(*) FROM studentdata WHERE rollno = @rollno";


                    myCommand.Parameters.Add("@rollno", SqlDbType.VarChar).Value = rollno;

                    SqlDataReader myReader = myCommand.ExecuteReader();
                    while (myReader.Read())
                    {
                       result = myReader.ToString();

                    }

                }
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            return "an error occured";
        }

        return result;
     }

   } 

}

If I run this code, I get output as “System.Data.SqlClient.SqlDataReader” which is not what i want

Answer 1

Don’t use a data reader for this you only have one result which is a row count so use ExecuteScalar() and use an int as type for result:

int result = Convert.ToInt32(myCommand.ExecuteScalar());

(Alternatively you can get the string value with your current query using result = myReader.GetInt32(0).ToString(); – don’t do this though)