How to call Stored Procedure and use of ExecuteReader and Excecute Scalar

The following code demonstrates few things in C#.NET:

//CALLING THE STORED PROCEDURE IN SQL SERVER

SqlConnection conn = new SqlConnection("Server=(local);DataBase=Rohit;Integrated Security=SSPI");

            conn.Open();

            int vEmpno;

            String vEname;

            int vSalary;

            //insert command

            //Pick all the values from the textboxes

            vEmpno = Convert.ToInt32(textBox1.Text);

            vEname = textBox2.Text;

            vSalary = Convert.ToInt32(textBox3.Text);

            SqlCommand cmd = new SqlCommand("P1", conn);

            cmd.CommandType = CommandType.StoredProcedure;

            cmd.Parameters.AddWithValue("@vEmpno", vEmpno);

            cmd.Parameters.AddWithValue("@vEname", vEname);

            cmd.Parameters.AddWithValue("@vSalary", vSalary);

            cmd.ExecuteNonQuery();

            MessageBox.Show("Record Saved");

            conn.Close();

How To display the Employee Numbers and Enames from Table for a selected job

SqlConnection conn = new SqlConnection("Server=(local);DataBase=Rohit;Integrated Security=SSPI");

            conn.Open();

            //Get the selected job from Listbox3

            String vSelectedJob = listBox3.SelectedItem.ToString();

            String vQuery = "Select * from Emp where job='"+vSelectedJob+"'";

            SqlCommand cmd = new SqlCommand(vQuery, conn);

            SqlDataReader vDr=cmd.ExecuteReader();

            listBox1.Items.Clear();

            listBox2.Items.Clear();

            while (vDr.Read())

            {

                listBox1.Items.Add(vDr["Empno"]);

                listBox2.Items.Add(vDr["Ename"]);

            }

            conn.Close();

//To get all the distinct jobs from Emp

           SqlConnection conn = new SqlConnection("Server=(local);DataBase=Rohit;Integrated Security=SSPI");

            conn.Open();

            String vQuery = "Select distinct(job) from Emp";

            SqlCommand cmd = new SqlCommand(vQuery, conn);

            SqlDataReader vDr = cmd.ExecuteReader();

            while (vDr.Read())

            {

                listBox3.Items.Add(vDr[0]);

            }

            conn.Close();

//USE OF EXECUTE SCALAR

            SqlConnection conn = new SqlConnection("Server=(local);DataBase=Rohit;Integrated Security=SSPI");

            conn.Open();

            int vEmpno = Convert.ToInt32(textBox1.Text);

            String vQuery = "Select ename from emp where Empno = "+ vEmpno;

           

            SqlCommand cmd = new SqlCommand(vQuery, conn);

            Object vobj = cmd.ExecuteScalar();

            if (vobj == null)

            {

                MessageBox.Show("Sorry no record found");

            }

            else

            {

                textBox2.Text = vobj.ToString();

            }

            conn.Close();  

Happy Coding. Keep on trying