Transactions and stored proc in SQL SERVER 2014

Question

Can someone guide/show me how to make a transaction in sql server and how to call that in my code behind. The details are presented below. 

 

I created a stored procedure as shown below:

ALTER PROCEDURE [dbo].[spInsertCashierSalesDetails_V2_From_Underwriting]
    -- Add the parameters for the stored procedure here
    (
            @ID int,
            @TransactionNumber nvarchar(50),
            @CustomerNo nvarchar(50),
            @CustomerName nvarchar(50),
            @PolicyCINo nvarchar(50),
            @MotorCINo nvarchar(50),
            @ProductType nvarchar(50),
            @COA_Code nvarchar(50),
            @Debit decimal(18,2),
            @Credit decimal(18,2),
            @TransactionType nvarchar(50),
            @AgentID nvarchar(50),
            @Username nvarchar(50))
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    -- Insert statements for procedure here
    INSERT INTO [dbo].[CashierSalesDetails_V2]
           (
            [TransactionNumber]
            ,[CustomerNo]
            ,[CustomerName]
            ,[PolicyCINo]
            ,[MotorCINo]
            ,[ProductType]
            ,[COA_Code]
            ,[Debit]
            ,[Credit]
            ,[TransactionType]
            ,[AgentID]
            ,[Username])
     VALUES
           (
           @TransactionNumber,
           @CustomerNo,
           @CustomerName,
           @PolicyCINo,
           @MotorCINo,
           @ProductType,
           @COA_Code,
           @Debit,
           @Credit,
           @TransactionType,
           @AgentID,
           @Username)
END

In my code behind in C#, I called this sp

public int InsertCashierDetailsv2_FromUnderwriting(CashierDetailsTableV2 cashierDetailsTable)
        {
            using (SqlConnection con = DBConnection.GetDbCon())
            {
                SqlCommand cmd = new SqlCommand("spInsertCashierSalesDetails_V2_From_Underwriting", con);
                cmd.CommandType = CommandType.StoredProcedure;
                con.Open();

                try
                {
                    cmd.Parameters.AddWithValue("@ID", cashierDetailsTable.ID);
                    cmd.Parameters.AddWithValue("@TransactionNumber", cashierDetailsTable.TransactionNumber);
                    cmd.Parameters.AddWithValue("@CustomerNo", cashierDetailsTable.CustomerNo);
                    cmd.Parameters.AddWithValue("@CustomerName", cashierDetailsTable.CustomerName);
                    cmd.Parameters.AddWithValue("@PolicyCINo", cashierDetailsTable.PolicyCINo ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@MotorCINo", cashierDetailsTable.MotorCINo ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@ProductType", cashierDetailsTable.ProductType);
                    cmd.Parameters.AddWithValue("@COA_Code", cashierDetailsTable.COA_Code);
                    cmd.Parameters.AddWithValue("@Debit", cashierDetailsTable.Debit);
                    cmd.Parameters.AddWithValue("@Credit", cashierDetailsTable.Credit);
                    cmd.Parameters.AddWithValue("@TransactionType", cashierDetailsTable.TransactionType);
                    cmd.Parameters.AddWithValue("@AgentID", cashierDetailsTable.AgentID);
                    cmd.Parameters.AddWithValue("@Username", cashierDetailsTable.Username);

                    return cmd.ExecuteNonQuery();
                }
                catch
                {
                    throw;
                }
                finally
                {
                    cmd.Dispose();
                    con.Close();
                    con.Dispose();
                }
            }
        }

I also created 4 methods to insert almost the same data except for the COA_Code, Debit and Credit as shown below:

private void InsertCashierDetailsCOAAR()
      {
          CashierDetailsTableV2 cashierDetails = new CashierDetailsTableV2();
          CashierDetailsDA insertCashierDetails = new CashierDetailsDA();
          try
          {
              cashierDetails.TransactionNumber = lblTransactionNumber.Text;
              cashierDetails.CustomerNo = txtCustomerNo.Text;
              cashierDetails.CustomerName = txtCustomerName.Text;
              cashierDetails.MotorCINo = ddlMotorCI.SelectedValue;
              cashierDetails.ProductType = txtProductType.Text;
              cashierDetails.COA_Code = ddlCOAAR.SelectedItem.Text;
              cashierDetails.Debit = Convert.ToDecimal(txtTotalPrem.Text); //insurance premium
              cashierDetails.TransactionType = lblTransactionType.Text;
              cashierDetails.AgentID = lblAgentCode.Text;
              cashierDetails.Username = lblUserName.Text;

              insertCashierDetails.InsertCashierDetailsv2_FromUnderwriting(cashierDetails);

              InsertCashierDetailsCOAIP();
          }
          catch (Exception ex)
          {
              throw ex;
          }

      }
      private void InsertCashierDetailsCOAIP()
      {
          CashierDetailsTableV2 cashierDetails = new CashierDetailsTableV2();
          CashierDetailsDA insertCashierDetails = new CashierDetailsDA();
          try
          {
              cashierDetails.TransactionNumber = lblTransactionNumber.Text;
              cashierDetails.CustomerNo = txtCustomerNo.Text;
              cashierDetails.CustomerName = txtCustomerName.Text;
              cashierDetails.MotorCINo = ddlMotorCI.SelectedValue;
              cashierDetails.ProductType = txtProductType.Text;
              cashierDetails.COA_Code = ddlCOAIP.SelectedItem.Text;
              cashierDetails.Credit = Convert.ToDecimal(txtNetPremium2.Text); //insurance premium
              cashierDetails.TransactionType = lblTransactionType.Text;
              cashierDetails.AgentID = lblAgentCode.Text;
              cashierDetails.Username = lblUserName.Text;

              insertCashierDetails.InsertCashierDetailsv2_FromUnderwriting(cashierDetails);

              InsertCashierDetailsCOAOT();
          }
          catch (Exception ex)
          {
              throw ex;
          }
      }
      private void InsertCashierDetailsCOAOT()
      {
          CashierDetailsTableV2 cashierDetails = new CashierDetailsTableV2();
          CashierDetailsDA insertCashierDetails = new CashierDetailsDA();
          try
          {
              cashierDetails.TransactionNumber = lblTransactionNumber.Text;
              cashierDetails.CustomerNo = txtCustomerNo.Text;
              cashierDetails.CustomerName = txtCustomerName.Text;
              cashierDetails.MotorCINo = ddlMotorCI.SelectedValue;
              cashierDetails.ProductType = txtProductType.Text;
              cashierDetails.COA_Code = ddlCOAOT.SelectedItem.Text;
              cashierDetails.Credit = Convert.ToDecimal(txtVat.Text); // vat
              cashierDetails.TransactionType = lblTransactionType.Text;
              cashierDetails.AgentID = lblAgentCode.Text;
              cashierDetails.Username = lblUserName.Text;

              insertCashierDetails.InsertCashierDetailsv2_FromUnderwriting(cashierDetails);

              InsertCashierDetailsCOARF();
          }
          catch (Exception ex)
          {
              throw ex;
          }
      }
      private void InsertCashierDetailsCOARF()
      {
          CashierDetailsTableV2 cashierDetails = new CashierDetailsTableV2();
          CashierDetailsDA insertCashierDetails = new CashierDetailsDA();
          try
          {
              cashierDetails.TransactionNumber = lblTransactionNumber.Text;
              cashierDetails.CustomerNo = txtCustomerNo.Text;
              cashierDetails.CustomerName = txtCustomerName.Text;
              cashierDetails.MotorCINo = ddlMotorCI.SelectedValue;
              cashierDetails.ProductType = txtProductType.Text;
              cashierDetails.COA_Code = ddlCOARF.SelectedItem.Text;
              cashierDetails.Credit = Convert.ToDecimal(txtRegistry.Text); // registry fee
              cashierDetails.TransactionType = lblTransactionType.Text;
              cashierDetails.AgentID = lblAgentCode.Text;
              cashierDetails.Username = lblUserName.Text;

              insertCashierDetails.InsertCashierDetailsv2_FromUnderwriting(cashierDetails);

              InsertCashierHeader();
          }
          catch (Exception ex)
          {
              throw ex;
          }
      }

I know that there is a better way of doing this. Thanks in advance.