csharp Sql Server Ado.NET

Posted 2021-05-12

USE [NORTHWND]
GO

/****** Object:  StoredProcedure [dbo].[GetAllEmployeeDetails]    Script Date: 06/09/2017 17:11:47 ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE PROCEDURE [dbo].[GetAllEmployeeDetails]
AS
BEGIN
      SET NOCOUNT ON;
      SELECT FirstName, LastName, BirthDate, City, Country
      FROM Employees
END
GO

var connString = ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString;
            List<Employee> employees1 = new List<Employee>();

            using (var conn = new SqlConnection(connString))
            {
                conn.Open();
                var cmd = new SqlCommand("SELECT * FROM Employees WHERE EmployeeID > @valore ORDER BY EmployeeID DESC", conn);
                cmd.Parameters.AddWithValue("@valore", 5);

                using (var reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        var employeeID = Convert.ToInt32(reader["EmployeeID"]);
                        string lastName = reader["LastName"].ToString();
                        string firstName = reader["FirstName"].ToString();

                        employees1.Add(new Employee
                        {
                            EmployeeID = employeeID,
                            LastName = lastName,
                            FirstName = firstName
                        });
                    }
                }
                cmd.Dispose();
            }

            using (var conn = new SqlConnection(connString))
            {
                conn.Open();
                SqlTransaction myTrans = conn.BeginTransaction();               

                var cmd = new SqlCommand("UPDATE Employees SET LastName = @lastName WHERE EmployeeID = @valore", conn);
                cmd.Parameters.AddWithValue("@lastName", "Gates");
                cmd.Parameters.AddWithValue("@valore", 5);
                cmd.Transaction = myTrans;

                try
                {
                    var numRowsAffected = cmd.ExecuteNonQuery();
                    cmd.Transaction.Commit();                    
                }
                catch (Exception e)
                {
                    try
                    {
                        myTrans.Rollback();
                    }
                    catch (SqlException ex)
                    {
                        if (myTrans.Connection != null)
                        {
                            Console.WriteLine("An exception of type " + ex.GetType() +
                                              " was encountered while attempting to roll back the transaction.");
                        }
                    }
                }               
               
                cmd.Dispose();
            }

            List<Employee> employees2 = new List<Employee>();

            using (var conn = new SqlConnection(connString))
            {
                SqlCommand cmd = new SqlCommand("GetAllEmployeeDetails", conn);
                cmd.CommandType = CommandType.StoredProcedure;

                //SqlParameter RetVal = cmd.Parameters.Add("RetVal", SqlDbType.Int);
                //RetVal.Direction = ParameterDirection.ReturnValue;
                //SqlParameter IdIn = cmd.Parameters.Add("@au_idIN", SqlDbType.VarChar, 11);
                //IdIn.Direction = ParameterDirection.Input;
                //SqlParameter NumTitles = cmd.Parameters.Add("@numtitlesout", SqlDbType.VarChar, 11);
                //NumTitles.Direction = ParameterDirection.Output;

                conn.Open();

                using (SqlDataReader reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {                        
                        string lastName = reader["LastName"].ToString();
                        string firstName = reader["FirstName"].ToString();

                        employees2.Add(new Employee
                        {                            
                            LastName = lastName,
                            FirstName = firstName
                        });
                    };   
                }
            }