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s USING THE CSLA .NET BASE CLASSES in VB.NET
CHAPTER 7 s USING THE CSLA .NET BASE CLASSES PDF417 Generator In Visual Basic .NET Using Barcode generation for .NET Control to generate, create PDF 417 image in Visual Studio .NET applications. www.OnBarcode.comScanning PDF417 In VB.NET Using Barcode reader for .NET Control to read, scan read, scan image in Visual Studio .NET applications. www.OnBarcode.comEditable Child Collection
Make Data Matrix In Visual Basic .NET Using Barcode printer for Visual Studio .NET Control to generate, create DataMatrix image in .NET applications. www.OnBarcode.comUPC - 13 Printer In Visual Basic .NET Using Barcode drawer for Visual Studio .NET Control to generate, create EAN 13 image in VS .NET applications. www.OnBarcode.comThe most common type of collection is one that is contained within a parent object to manage a collection of child objects for that parent; like ProjectResources and ResourceAssignments in the sample application. Drawing Barcode In Visual Basic .NET Using Barcode generator for VS .NET Control to generate, create Barcode image in .NET applications. www.OnBarcode.comQR Code JIS X 0510 Drawer In VB.NET Using Barcode printer for .NET framework Control to generate, create QR-Code image in Visual Studio .NET applications. www.OnBarcode.coms Note that the parent object here might be a root object, or it might be a child itself child objects can be Tip nested, if that s what the business object model requires. In other words, this concept supports not only root-child, but also child-grandchild and grandchild-to-great-grandchild relationships. UCC.EAN - 128 Printer In VB.NET Using Barcode drawer for Visual Studio .NET Control to generate, create EAN / UCC - 13 image in .NET framework applications. www.OnBarcode.comPainting Rationalized Codabar In Visual Basic .NET Using Barcode creator for .NET Control to generate, create NW-7 image in .NET applications. www.OnBarcode.comA child collection class inherits from BusinessListBase and calls MarkAsChild() during its creation process to indicate that it s operating in child mode. This also means that it won t be directly retrieved or updated by the DataPortal, but instead will be retrieved or updated by its parent object: <Serializable()> _ Public Class EditableChildList Inherits BusinessListBase(Of EditableChildList, EditableChild) #Region " Factory Methods " Friend Shared Function NewEditableChildList() As EditableChildList Return New EditableChildList End Function Friend Shared Function GetEditableChildList( _ ByVal dr As SqlDataReader) As EditableChildList Return New EditableChildList(dr) End Function Private Sub New() MarkAsChild() End Sub Private Sub New(ByVal dr As SqlDataReader) MarkAsChild() Fetch(dr) End Sub #End Region #Region " Data Access " Private Sub Fetch(ByVal dr As SqlDataReader) RaiseListChangedEvents = False While dr.Read Add(EditableChild.GetEditableChild(dr)) End While RaiseListChangedEvents = True End Sub Friend Sub Update(ByVal parent As Object) Scan PDF-417 2d Barcode In Visual C# Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications. www.OnBarcode.comDraw PDF-417 2d Barcode In None Using Barcode generation for Software Control to generate, create PDF 417 image in Software applications. www.OnBarcode.comCHAPTER 7 s USING THE CSLA .NET BASE CLASSES
Barcode Encoder In None Using Barcode generator for Software Control to generate, create Barcode image in Software applications. www.OnBarcode.comEncode UPC-A Supplement 2 In None Using Barcode creation for Font Control to generate, create Universal Product Code version A image in Font applications. www.OnBarcode.comRaiseListChangedEvents = False For Each item As EditableChild In DeletedList item.DeleteSelf() Next DeletedList.Clear() For Each item As EditableChild In Me If item.IsNew Then item.Insert(parent) Else item.Update(parent) End If Next RaiseListChangedEvents = True End Sub #End Region End Class As you can see, this code is very similar to a root collection in structure. The differences start with the factory methods. Since only a parent object can create or fetch an instance of this class, the Shared factory methods are scoped as Friend. The Shared method to create an object simply returns a new collection object. As with the EditableChild template, the constructor calls MarkAsChild() to indicate that this is a child object. Likewise, the Shared method to load the child collection with data creates a new collection object and then calls a parameterized constructor just like in the EditableChild template. That constructor calls a Fetch() method to load the data. The Update() method is identical to the DataPortal_Update() method in the EditableRootList. It loops through the list of deleted child objects, calling their DeleteSelf() methods, and then loops through the active child objects, calling Insert() or Update() as appropriate. Notice, however, that the Update() method accepts a reference to the parent object as a parameter, and this value is provided to the child objects Insert() and Update() methods. As discussed earlier, this allows the child objects to use data from the parent object as needed for things like foreign key values and so forth. Encode EAN 13 In None Using Barcode generator for Excel Control to generate, create EAN-13 image in Excel applications. www.OnBarcode.comEAN 13 Printer In Java Using Barcode generator for Java Control to generate, create European Article Number 13 image in Java applications. www.OnBarcode.comRead-Only Business Objects
GS1-128 Generator In Java Using Barcode creator for BIRT reports Control to generate, create EAN128 image in BIRT applications. www.OnBarcode.comCode39 Generation In None Using Barcode generation for Office Word Control to generate, create Code 3 of 9 image in Word applications. www.OnBarcode.comSometimes, an application may need an object that provides data in a read-only fashion. For a readonly list of data, there s ReadOnlyListBase; but if the requirement is for a single object containing read-only data, it should inherit from ReadOnlyBase. This is one of the simplest types of object to create, since it does nothing more than retrieve and return data, as shown here: <Serializable()> _ Public Class ReadOnlyRoot Inherits ReadOnlyBase(Of ReadOnlyRoot) #Region " Business Methods " Private mId As Integer EAN / UCC - 13 Creator In .NET Framework Using Barcode generation for ASP.NET Control to generate, create UCC.EAN - 128 image in ASP.NET applications. www.OnBarcode.comEAN 128 Decoder In Visual C# Using Barcode recognizer for .NET framework Control to read, scan read, scan image in .NET applications. www.OnBarcode.comCHAPTER 7 s USING THE CSLA .NET BASE CLASSES
Drawing Code 128 In None Using Barcode maker for Online Control to generate, create Code 128 Code Set C image in Online applications. www.OnBarcode.comUSS Code 39 Creation In Java Using Barcode creation for Java Control to generate, create Code 39 Full ASCII image in Java applications. www.OnBarcode.comPublic ReadOnly Property Id() As Integer Get CanReadProperty(True) Return mId End Get End Property Protected Overrides Function GetIdValue() As Object Return mId End Function #End Region #Region " Authorization Rules " Protected Overrides Sub AddAuthorizationRules() ' TODO: add authorization rules 'AuthorizationRules.AllowRead("", "") End Sub Public Shared Function CanGetObject() As Boolean ' TODO: customize to check user role 'Return ApplicationContext.User.IsInRole("") Return True End Function #End Region #Region " Factory Methods " Public Shared Function GetReadOnlyRoot(ByVal id As Integer) As ReadOnlyRoot Return DataPortal.Create(Of ReadOnlyRoot)(New Criteria(id)) End Function Private Sub New() ' require use of factory methods End Sub #End Region #Region " Data Access " <Serializable()> _ Private Class Criteria Private mId As Integer Public ReadOnly Property Id() As Integer Get Return mId End Get End Property Public Sub New(ByVal id As Integer) mId = id End Sub End Class
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