Conncection string

In addition to the first answer, you can check out http://www.aspnet101.com/2008/01/a-beginners-guide-to-the-connection-string/[^].

put this class on a .cs file in your project. Add a new item (Service Database) which will create a .mdf file (the database file for MSSQL). Double click on the file and open server explorer (view menu). Open the properties tab, and get the ConnectionString property. Replace the connectString field in my DataHelperMS class with the connection string. Please double the backslashes to avoid a compiler error.

In your event handler, just create a new DataHelperMS class and call its ExecuteDataSet / ExecuteNonQuery Methods. It should work perfectly

public class DataHelperMS
    {
        public static String connectString = "Data Source=.;AttachDbFilename=\"C:\\Users\\RR\\Documents\\Visual Studio 2008\\Projects\\PhilNits Exam Simulator\\PhilNits Exam Simulator\\exam.mdf\";Integrated Security=True;User Instance=True";

        public String ConnectionString
        {
            get {
         //       String connection = ConfigurationManager.ConnectionStrings["DataConnectionString"].ConnectionString;
           //     String result = String.Format(connection , Environment.CurrentDirectory.Substring(0, Environment.CurrentDirectory.IndexOf("\\bin\\")+1 ) );
        //      result = connectString;
                return connectString;
             }
        }
        SqlConnection conn;
        public DataHelperMS()
        {
            String conString = ConnectionString;
            this.conn = new SqlConnection(conString);
        }
        
        public int ExecuteNonQuery(String sql)
        {
            int result = 0;
            try
            {
                conn.Open();
                SqlCommand command = conn.CreateCommand();
                command.CommandText = sql;
                result = command.ExecuteNonQuery();
            }
            catch (SqlException)
            {
                result = 0;
                throw;
            }
            finally
            {
                conn.Close();
            }
            return result;
        }
        public DataSet ExecuteDataSet(String sql)
        {
            // Ensure that the current culture is US-English 
            //Thread.CurrentThread.CurrentCulture = new System.Globalization.CultureInfo("en-US");
            DataSet result = null;
            try
            {
                conn.Open();
                SqlCommand command = conn.CreateCommand();
                command.CommandText = sql;
                result = ConvertDataReaderToDataSet(command.ExecuteReader());
            }
            catch (SqlException ex)
            {
                ex.ToString();
                result = null;
                throw;
            }
            finally
            {
                conn.Close();
            }
            return result;
        }
        public static DataSet ConvertDataReaderToDataSet(SqlDataReader reader)
        {
            DataSet dataSet = new DataSet();
            do
            {
                // Create new data table
                DataTable schemaTable = reader.GetSchemaTable();
                DataTable dataTable = new DataTable();
                if (schemaTable != null)
                {
                    // A query returning records was executed
                    for (int i = 0; i < schemaTable.Rows.Count; i++)
                    {
                        DataRow dataRow = schemaTable.Rows[i];
                        // Create a column name that is unique in the data table
                        string columnName = (string)dataRow["ColumnName"]; //+ "<C" + i + "/>";
                        // Add the column definition to the data table
                        DataColumn column = new DataColumn(columnName, (Type)dataRow["DataType"]);
                        try
                        {
                            dataTable.Columns.Add(column);
                        }
                        catch (DuplicateNameException)
                        {
                            int count = 0;
                            while (dataTable.Columns[columnName] != null)
                            {
                                columnName += count;
                                count++;
                            }
                            column.ColumnName = columnName;
                            dataTable.Columns.Add(column);
                        }
                    }
                    dataSet.Tables.Add(dataTable);
                    // Fill the data table we just created
                    while (reader.Read())
                    {
                        DataRow dataRow = dataTable.NewRow();
                        for (int i = 0; i < reader.FieldCount; i++)
                            dataRow[i] = reader.GetValue(i);
                        dataTable.Rows.Add(dataRow);
                    }
                }
                else
                {
                    // No records were returned
                    DataColumn column = new DataColumn("RowsAffected");
                    dataTable.Columns.Add(column);
                    dataSet.Tables.Add(dataTable);
                    DataRow dataRow = dataTable.NewRow();
                    dataRow[0] = reader.RecordsAffected;
                    dataTable.Rows.Add(dataRow);
                }
            }
            while (reader.NextResult());
            foreach (DataTable dt in dataSet.Tables)
            {
                dt.AcceptChanges();
            }
            return dataSet;
        }
        

    }