Developing 3-Tier Application in .NET 2.0 – Part 3

In this section, I will connect Business Logic Layer (BLL) to Data Access Layer and then User Interface Layer (UIL) to Business Logic Layer (BLL).

Note: If you are developing an enterprise application please see my next article on “Understanding 3-Tier vs. 3-Layer Architecture”.

Business Logic Layer Code
Namespace: Vishwa.Example.Business

Customer.vb : This class will communicate with previously designed Data Access Layer (DAL) in Part -2.

 

' Author : Vishwa

' Date : 10/15/2006

' Class : Customer Business Object

' Design Pattern: Domain Model and Identity Field

' Purpose: This class will act as Business Object and Business Logic Layer

Imports Vishwa.Example.Data

Namespace Vishwa.Example.Business

    Public Class Customer

        Private _custID As Integer = 0

        Private _custName As String = String.Empty

        Private _custDOB As DateTime = DateTime.MinValue

        Private _custAddress As String = String.Empty

        Private _dateCreated As DateTime = DateTime.Now

        Private _dateModified As DateTime = DateTime.Now

#Region "Constructor"

        Public Sub New()

        End Sub

#End Region

#Region "Properties"

        Public Property CustID() As Integer

            Get

                Return _custID

            End Get

            Set(ByVal value As Int32)

                _custID = value

            End Set

        End Property

        Public Property CustName() As String

            Get

                Return _custName

            End Get

            Set(ByVal value As String)

                _custName = value

            End Set

        End Property

        Public Property CustDOB() As DateTime

            Get

                Return _custDOB

            End Get

            Set(ByVal value As DateTime)

                _custDOB = value

            End Set

        End Property

        Public Property CustAddress() As String

            Get

                Return _custAddress

            End Get

            Set(ByVal value As String)

                _custAddress = value

            End Set

        End Property

        Public Property DateCreated() As DateTime

            Get

                Return _dateCreated

            End Get

            Set(ByVal value As DateTime)

                _dateCreated = value

            End Set

        End Property

        Public Property DateModified() As DateTime

            Get

                Return _dateModified

            End Get

            Set(ByVal value As DateTime)

                _dateModified = value

            End Set

        End Property

#End Region

#Region "--Customer Object Functions--- "

        Public Shared Function GetCustomer(ByVal custID As Integer) As Customer

            Return DataAccess.GetCustomers(custID)

        End Function

        Public Shared Function GetAllCustomer() As Generic.List(Of Customer)

            Return DataAccess.GetAllCustomers()

        End Function

        Public Shared Function AddCustomer() As Integer

            Dim custInfo As New Customer

            custInfo.CustID = 0

            custInfo.CustName = "unknown"

            custInfo.CustDOB = #1/1/1900#

            custInfo.CustAddress = "unknown"

            Return DataAccess.InsertCustomer(custInfo)

        End Function

        Public Shared Function AddCustomer(ByVal custInfo As Customer) As Integer

            Return DataAccess.InsertCustomer(custInfo)

        End Function

        Public Shared Function UpdateCustomer(ByVal custInfo As Customer) As Integer

            Return DataAccess.UpdateCustomer(custInfo)

        End Function

        Public Shared Function DeleteCustomer(ByVal custInfo As Customer) As Integer

            Return DataAccess.DeleteCustomer(custInfo)

        End Function

#End Region

    End Class

End Namespace

 

 

Now, we have Database, Data Access Layer(DAL) and Business Logic Layer (BLL) ready for last step - User Interface Layer (UIL).

User Interface Layer (UIL)
Namespace: Vishwa.Example.WebSite1

Let's add a Web Form in the Project and drop a GridView Control and Object Data Source Control on this page and make sure that you have following code in the Source.
Customer.Aspx
-----------------------------------------------------------------

Code Snippet

1. <%@ Page Language="VB" AutoEventWireup="false" CodeFile="Customer.aspx.vb" Inherits="Vishwa.Example.WebSite1.Customer" %>
2. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
3. <html xmlns="http://www.w3.org/1999/xhtml" >
4. <head id="Head1" runat="server" >
5. <title>Customer</title>
6. </head>
7. <body>
8. <form id="frmCustomer" runat="server">
9. <div style="text-align:center">
10. <h2 >Customer Maintenance</h2>
11. <asp:LinkButton ID="lnkAddNew" runat="server" Text="Add New" OnClick="InsertBlankRecord" EnableViewState="false" />
12. <asp:GridView ID="gdvCustomer" DataKeyNames="CustID" runat="server" AllowPaging="True" DataSourceID="odsCustomer" >
13. <Columns>
14. <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" />
15. </Columns>
16. <EmptyDataTemplate>
17. No Customer Record Found.
18. </EmptyDataTemplate>
19. </asp:GridView>
20. </div>
21. <asp:ObjectDataSource ID="odsCustomer" runat="server" DataObjectTypeName="Vishwa.Example.Business.Customer"
22. DeleteMethod="DeleteCustomer" SelectMethod="GetAllCustomer"
23. TypeName="Vishwa.Example.Business.Customer" UpdateMethod="UpdateCustomer">
24. </asp:ObjectDataSource>
25. </form>
26. </body>
27. </html>

--------------------------------------------------------------------------
Code File: Customer.Aspx.vb
--------------------------------------------------------------------------

Option Explicit On

Option Strict On

' Author : Vishwa@VishwaMohan.Com

' Date : 10/15/2006

' Class : Customer

' Purpose: To Get,Insert, Update and Delete Customer Record

Namespace Vishwa.Example.WebSite1

    Partial Class Customer

        Inherits System.Web.UI.Page

        Public Sub InsertBlankRecord(ByVal sender As Object, ByVal e As System.EventArgs)

            Vishwa.Example.Business.Customer.AddCustomer()

            gdvCustomer.DataBind()

        End Sub

    End Class

End Namespace

 

Code is complete now. Select Customer.aspx page in Project and Press F5 button (run). You will see the customer page as :

Case 1 : No Record.

 

Case 2: Click on Add New Link and a Blank new record with default value will be added

 

Case 3: Click on Edit link and enter a desired value for customer name and address and then click on Update link to update the record.

 

Case 4: Updated record is shown below. You can delete this record by clicking on Delete link. The record will be deleted and you will see the same screen presented in Case 1.

 

I hope this simple example helped you to understand and implement a 3 tier architecture using Visual Studio.NET 2005. If you have any questions or comments, please feel free to post and I will try to answer them.

Once you are able to understand these layer now, let's review the real information in next post.