When you separate your business layer from data access layer in two different assembly, you come across a situation as which data transfer method will be best for me. In this example, I went through various data transfer object currently available in .NET such as
Each option has its pros and cons, so depending on project one should choose as what best fits the need. In the following code I have tried to use all the four possibilities.
' <summary>
' Customer Business Object
' </summary>
' <remarks>
' Design Pattern: Domain Model and Identity Field
' </remarks>
Option Explicit On
Option Strict On
Imports Vishwa.Example.Data
Imports Vishwa.Example.Data.DataAccess
Namespace Example.Business
<Serializable()> _
Public Class CustomerBiz
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
' A Simple example of Business Logic to Get Customer Age
' Such logics are created in Business Logic/Object Layer
Public ReadOnly Property CustAge() As Long
Get
If _custDOB > DateTime.MinValue Then
Return DateDiff(DateInterval.Year, _custDOB, Now())
Else
Return 0
End If
End Get
End Property
#End Region
#Region "Customer Methods"
Public Function AddBlankCustomer() As Integer
Return DataProvider.InsertCustomer("unknown", DateTime.Now, "Unknown")
End Function
Public Overloads Function AddCustomer(ByVal custInfo As CustomerBiz) As Integer
Return DataProvider.InsertCustomer(custInfo.CustName, custInfo.CustDOB, "Unknown")
End Function
Public Overloads Function AddCustomer(ByVal custName As String, ByVal custDOB As DateTime, _
ByVal custAddress As String) As Integer
Return DataProvider.InsertCustomer(custName, custDOB, custAddress)
End Function
Public Overloads Function UpdateCustomer(ByVal custInfo As CustomerBiz) As Boolean
Return DataProvider.UpdateCustomer(custInfo.CustID, custInfo.CustName, custInfo.CustDOB, custInfo.CustAddress)
End Function
Public Overloads Function UpdateCustomer(ByVal custID As Integer, ByVal custName As String, _
ByVal custDOB As DateTime, ByVal custAddress As String) As Boolean
Return DataProvider.UpdateCustomer(custID, custName, custDOB, custAddress)
End Function
Public Overloads Function DeleteCustomer(ByVal custID As Integer) As Boolean
Return DataProvider.DeleteCustomer(custID)
End Function
Public Overloads Function DeleteCustomer(ByVal custInfo As CustomerBiz) As Boolean
Return DataProvider.DeleteCustomer(custInfo.CustID)
End Function
#Region "Get Customers From Custom Data Transfer Object"
Public Function GetCustomer(ByVal custID As Integer) As CustomerBiz
Dim custDTORec As New CustomerDTO
Dim custBIZRec As New CustomerBiz
custDTORec = DataProvider.GetCustomer(custID)
If Not custDTORec Is Nothing Then
custBIZRec = GetCustomerRow(custDTORec)
End If
Return custBIZRec
End Function
Public Function GetCustomers() As List(Of CustomerBiz)
Dim custBIZRecs As New List(Of CustomerBiz)
Dim custDTORecs As New List(Of CustomerDTO)
custDTORecs = DataProvider.GetCustomers
For Each custDTORec As CustomerDTO In custDTORecs
Dim custBIZRec As CustomerBiz = GetCustomerRow(custDTORec)
custBIZRecs.Add(custBIZRec)
Next
Return custBIZRecs
End Function
#End Region
#Region "Consuming Get Methods of Other Data Trasfer Objects"
#Region "Get Customers From DataSet Object"
Public Function GetCustomerFromDataSet(ByVal custID As Integer) As CustomerBiz
Dim custDataSet As New DataSet("Customer")
Dim custBIZRec As New CustomerBiz
custDataSet = DataProvider.GetCustomerAsDataSet(custID)
If Not custDataSet Is Nothing AndAlso custDataSet.Tables.Count = 1 Then
custBIZRec = GetCustomerRow(custDataSet.Tables(0).Rows(0))
End If
Return custBIZRec
End Function
Public Function GetCustomersFromDataSet() As List(Of CustomerBiz)
Dim custDataSet As New DataSet("Customers")
Dim custBIZRecs As New List(Of CustomerBiz)
custDataSet = DataProvider.GetCustomersAsDataSet()
If Not custDataSet Is Nothing AndAlso custDataSet.Tables.Count = 1 Then
For Each row As DataRow In custDataSet.Tables(0).Rows
Dim custBIZRec As CustomerBiz = GetCustomerRow(row)
custBIZRecs.Add(custBIZRec)
Next
End If
Return custBIZRecs
End Function
#End Region
#Region "Get Customers From DataTable Object"
Public Function GetCustomerFromDataTable(ByVal custID As Integer) As CustomerBiz
Dim custDataTable As New DataTable("Customer")
Dim custBIZRec As New CustomerBiz
custDataTable = DataProvider.GetCustomerAsDataTable(custID)
If Not custDataTable Is Nothing AndAlso custDataTable.Rows.Count > 0 Then
custBIZRec = GetCustomerRow(custDataTable.Rows(0))
End If
Return custBIZRec
End Function
Public Function GetCustomersFromDataTable() As List(Of CustomerBiz)
Dim custDataTable As New DataTable("Customers")
Dim custBIZRecs As New List(Of CustomerBiz)
custDataTable = DataProvider.GetCustomersAsDataTable()
If Not custDataTable Is Nothing AndAlso custDataTable.Rows.Count > 0 Then
For Each row As DataRow In custDataTable.Rows
Dim custBIZRec As CustomerBiz = GetCustomerRow(row)
custBIZRecs.Add(custBIZRec)
Next
End If
Return custBIZRecs
End Function
#End Region
#Region "Get Customers From XML"
Public Function GetCustomerFromXML(ByVal custID As Integer) As CustomerBiz
Dim custBIZRecs As New List(Of CustomerBiz)
Dim custBIZRec As New CustomerBiz
Dim custXMLString As String = DataProvider.GetCustomersAsXMLString()
If custXMLString.Length > 0 Then
custBIZRecs = ReadCustomerXML(custXMLString)
If Not custBIZRecs.Count > 0 Then custBIZRec = custBIZRecs(0)
End If
Return custBIZRec
End Function
Public Function GetCustomersFromXML() As List(Of CustomerBiz)
Dim custBIZRecs As New List(Of CustomerBiz)
Dim custXMLString As String = DataProvider.GetCustomersAsXMLString()
If custXMLString.Length > 0 Then
custBIZRecs = ReadCustomerXML(custXMLString)
End If
Return custBIZRecs
End Function
#End Region
#Region "Get Customers From ArrayList Object"
Public Function GetCustomerFromArrayList(ByVal custID As Integer) As CustomerBiz
Dim custBIZRec As New CustomerBiz
Dim custArrList As New ArrayList()
custArrList = DataProvider.GetCustomerAsArrayList(custID)
If Not custArrList Is Nothing AndAlso custArrList.Count > 0 Then
custBIZRec = GetCustomerRow(custArrList)
End If
Return custBIZRec
End Function
Public Function GetCustomersFromArrayList() As List(Of CustomerBiz)
Dim custBIZRecs As New List(Of CustomerBiz)
Dim custArrList As New ArrayList()
custArrList = DataProvider.GetCustomersAsArrayList()
If Not custArrList Is Nothing AndAlso custArrList.Count > 0 Then
For Each row As ArrayList In custArrList
Dim custBIZRec As CustomerBiz = GetCustomerRow(row)
custBIZRecs.Add(custBIZRec)
Next
End If
Return custBIZRecs
End Function
#End Region
#End Region
#Region "Common Methods to Transfer data from DTO to Business Object"
Private Function GetCustomerRow(ByVal row As DataRow) As CustomerBiz
Dim custBIZRec As New CustomerBiz
If Not IsDBNull(row.Item("Cust_ID")) Then custBIZRec.CustID = CInt(row.Item("Cust_ID"))
If Not IsDBNull(row.Item("Cust_DOB")) Then custBIZRec.CustDOB = CDate(row.Item("Cust_DOB"))
If Not IsDBNull(row.Item("Cust_Name")) Then custBIZRec.CustName = row.Item("Cust_Name").ToString
If Not IsDBNull(row.Item("Cust_Address")) Then custBIZRec.CustAddress = row.Item("Cust_Address").ToString
If Not IsDBNull(row.Item("Date_Created")) Then custBIZRec.DateCreated = CDate(row.Item("Date_Created"))
If Not IsDBNull(row.Item("Date_Modified")) Then custBIZRec.DateModified = CDate(row.Item("Date_Modified"))
Return custBIZRec
End Function
Private Function GetCustomerRow(ByVal custDTORec As CustomerDTO) As CustomerBiz
Dim custBIZRec As New CustomerBiz
custBIZRec.CustID = custDTORec.CustID
custBIZRec.CustName = custDTORec.CustName
custBIZRec.CustDOB = custDTORec.CustDOB
custBIZRec.CustAddress = custDTORec.CustAddress
custBIZRec.DateCreated = custDTORec.DateCreated
custBIZRec.DateModified = custDTORec.DateModified
Return custBIZRec
End Function
Private Function GetCustomerRow(ByVal custArrList As ArrayList) As CustomerBiz
Dim custBIZRec As New CustomerBiz
If IsNumeric(custArrList.Item(0)) Then custBIZRec.CustID = CInt(custArrList.Item(0))
If Not custArrList.Item(1) Is Nothing Then custBIZRec.CustName = custArrList.Item(1).ToString
If IsDate(custArrList.Item(2)) Then custBIZRec.CustDOB = CDate(custArrList.Item(2))
If Not custArrList.Item(3) Is Nothing Then custBIZRec.CustAddress = custArrList.Item(3).ToString
If IsDate(custArrList.Item(4)) Then custBIZRec.DateCreated = CDate(custArrList.Item(4))
If IsDate(custArrList.Item(5)) Then custBIZRec.DateModified = CDate(custArrList.Item(5))
Return custBIZRec
End Function
Private Function ReadCustomerXML(ByVal xmlDocString As String) As List(Of CustomerBiz)
Dim customers As New List(Of CustomerBiz)
Dim status As Integer = 0
Dim statusDescription As String = String.Empty
Dim uniEncoding As New System.Text.ASCIIEncoding()
Dim stringBytes As Byte() = uniEncoding.GetBytes(xmlDocString)
Dim xmlDocSteam As New System.IO.MemoryStream(stringBytes, 0, stringBytes.Length)
Using xmlDocReader As System.Xml.XmlReader = System.Xml.XmlReader.Create(xmlDocSteam)
xmlDocReader.Read()
xmlDocReader.MoveToContent()
While xmlDocReader.Read()
If xmlDocReader.NodeType = System.Xml.XmlNodeType.Element And xmlDocReader.Name = "Customer" Then
Dim custRec As New CustomerBiz
While (xmlDocReader.Read() And xmlDocReader.Name <> "Customer")
If xmlDocReader.Name.Length > 0 Then
If xmlDocReader.Name = "Cust_ID" Then custRec.CustID = xmlDocReader.ReadElementContentAsInt("Cust_ID", "")
If xmlDocReader.Name = "Cust_Name" Then custRec.CustName = xmlDocReader.ReadElementContentAsString("Cust_Name", "")
If xmlDocReader.Name = "Cust_DOB" Then custRec.CustDOB = xmlDocReader.ReadElementContentAsDateTime("Cust_DOB", "")
If xmlDocReader.Name = "Cust_Address" Then custRec.CustAddress = xmlDocReader.ReadElementContentAsString("Cust_Address", "")
If xmlDocReader.Name = "Date_Created" Then custRec.DateCreated = xmlDocReader.ReadElementContentAsDateTime("Date_Created", "")
If xmlDocReader.Name = "Date_Modified" Then custRec.DateModified = xmlDocReader.ReadElementContentAsDateTime("Date_Modified", "")
End If
End While
customers.Add(custRec)
End If
End While
End Using
xmlDocSteam.Close()
Return customers
End Function
#End Region
#End Region
End Class
End Namespace
Compiled Assembly Name: Vishwa.Example.Business.dll
Now you can use the reference of the above assembly for customer object in your ASP.NET Web Page and test the functionality.
