RFC Architecture for Finance Project (The Invoicing Project)

Business class structure and code

Invoice has two business classes invoice class i.e. "lsInvoice" and product class i.e. "ClsProduct". Both of these call the "ClsInvoiceDB" class to database operations.

Business class and code explanation

Below is the "insert" method of "clsInvoice" class. It actually creates the object of "clsInvoiceDB" to connect to the SQL Server database.

public void Insert()
{
clsInvoiceDB objInvoiceDB = new clsInvoiceDB();
objInvoiceDB.InsertInvoice(_InvoiceReference, _InvoiceComments,
_InvoiceDate, _ProductId, _Qty, _Amount, _TaxAmount, _PaidAmount,
_CustomerName, _CustomerAddress, _UnitCost);
}

The insert invoice class code is something as shown below.

public void InsertInvoice(string _InvoiceReference, string _InvoiceComments, DateTime _InvoiceDate, int _productId,
int _Qty, double _Amount, double _TaxAmount, double _PaidAmount, string _CustomerName, string _CustomerAddress, double _UnitCost)
{
SqlConnection ObjConnection = new SqlConnection();
ObjConnection.ConnectionString = ConfigurationSettings.AppSetting
["ConnectionString"];
ObjConnection.Open();
SqlCommand objCommand = new SqlCommand();
objCommand.Connection = ObjConnection;
objCommand.CommandText = "usp_InsertInvoice";
objCommand.CommandType = CommandType.StoredProcedure;
objCommand.Parameters.Add(new SqlParameter("InvoiceReference", _InvoiceReference));
objCommand.Parameters.Add(new SqlParameter("@InvoiceComments", _InvoiceComments));
objCommand.Parameters.Add(new SqlParameter("@InvoiceDate", _InvoiceDate));
objCommand.Parameters.Add(new SqlParameter("@ProductId", _productId));
objCommand.Parameters.Add(new SqlParameter("@Qty", _Qty));
objCommand.Parameters.Add(new SqlParameter("@Amount", _Amount));
objCommand.Parameters.Add(new SqlParameter("@TaxAmount", _TaxAmount));
objCommand.Parameters.Add(new SqlParameter("@PaidAmount", _PaidAmount));
objCommand.Parameters.Add(new SqlParameter("@CustomerName", _CustomerName));
objCommand.Parameters.Add(new SqlParameter("@CustomerAddress", _CustomerAddress));
objCommand.Parameters.Add(new SqlParameter("@UnitCost", _UnitCost));
objCommand.ExecuteNonQuery();
ObjConnection.Close();
}

In the same way other methods of the business component and DAL interact. I am not pasting the code here as the article will become bulky. You can download the project from the codeplex to get a fell of the same.

ASPX pages

There are two ASPX pages one is the Invoice entry screen (InvoiceEntry.aspx) and the second is the product selection screen (SelectProducts.aspx). The UI consumes the business object in a very standard format. To get more understanding you can see the "setObjectFromUI" method where all the values from the UI is passed to the business object.

public void setObjectFromUI(clsInvoice objInvoice)
{
try
{
objInvoice.CustomerName = txtCustomerName.Text;
objInvoice.CustomerAddress = txtCustomerAddress.Text;
objInvoice.InvoiceComments = txtComments.Text;
objInvoice.InvoiceReference = txtInvoiceNumber.Text;
}
}

Finally in the button events the operations of the classes like insert , update and delete is called. For instance you can see in the update invoice click event we have called the "Update" operation. Any exceptions raised from the user interface is finally caught and displayed in the error message label

protected void btnUpdateInvoice_Click(object sender, EventArgs e)
{
clsInvoice objInvoice = new clsInvoice();
try
{
setObjectFromUI(objInvoice);
objInvoice.Update();
clearText();
LoadGrid();
clearSession();
}
catch (Exception ex)
{
lblErrorMessage.Text = ex.Message.ToString();
}
}

The whole project goes with the same style of coding business object, DAL and the consumption in the UI. So if you are able to follow the above code you should be able to understand the other part of the project also.

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