Assignment in VB.NET

Generating PDF-417 2d barcode in VB.NET Assignment

Assignment
Paint PDF-417 2d Barcode In VB.NET
Using Barcode creation for VS .NET Control to generate, create PDF417 image in Visual Studio .NET applications.
www.OnBarcode.com
Scan PDF-417 2d Barcode In VB.NET
Using Barcode scanner for .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
The Assignment class contains the behaviors common to both ProjectResource and ResourceAssignment, as designed in 6. Figure 8-4 shows the collaboration relationship between these objects.
Create Barcode In VB.NET
Using Barcode generator for VS .NET Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
Code128 Drawer In VB.NET
Using Barcode generator for Visual Studio .NET Control to generate, create USS Code 128 image in .NET applications.
www.OnBarcode.com
Figure 8-4. Objects collaborating with Assignment
European Article Number 13 Maker In VB.NET
Using Barcode generator for .NET Control to generate, create UPC - 13 image in Visual Studio .NET applications.
www.OnBarcode.com
Data Matrix ECC200 Printer In VB.NET
Using Barcode printer for Visual Studio .NET Control to generate, create Data Matrix 2d barcode image in .NET applications.
www.OnBarcode.com
Since Assignment only implements behaviors and contains no data, it is declared as a Module: Friend Module Assignment Notice that it doesn t inherit from any CSLA .NET base classes. It has no need, since it is merely a collection of common behaviors. Specifically, it contains a business method, a custom validation rule, and a set of data access methods.
Code 39 Printer In VB.NET
Using Barcode encoder for .NET Control to generate, create USS Code 39 image in Visual Studio .NET applications.
www.OnBarcode.com
European Article Number 8 Creator In VB.NET
Using Barcode drawer for .NET framework Control to generate, create GS1 - 8 image in VS .NET applications.
www.OnBarcode.com
CHAPTER 8 s BUSINESS OBJECT IMPLEMENTATION
PDF 417 Recognizer In Visual Basic .NET
Using Barcode recognizer for .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Drawing PDF-417 2d Barcode In None
Using Barcode maker for Font Control to generate, create PDF417 image in Font applications.
www.OnBarcode.com
Business Methods
QR Creator In None
Using Barcode creator for Font Control to generate, create QR Code JIS X 0510 image in Font applications.
www.OnBarcode.com
Barcode Maker In Java
Using Barcode creation for Eclipse BIRT Control to generate, create Barcode image in BIRT applications.
www.OnBarcode.com
When a resource is associated with a project, the date of that association is recorded. Though it may seem somewhat trivial, the code to determine that date value is a common behavior between ProjectResource and ResourceAssignment, so it is implemented in the Assignment class: Public Function GetDefaultAssignedDate() As Date Return Today End Function This is an example of the concept of normalization of behavior I discussed in 6.
Drawing EAN / UCC - 14 In .NET
Using Barcode encoder for .NET Control to generate, create GTIN - 128 image in .NET applications.
www.OnBarcode.com
Encode DataMatrix In Objective-C
Using Barcode drawer for iPad Control to generate, create ECC200 image in iPad applications.
www.OnBarcode.com
Validation Rules
GS1 - 13 Decoder In Visual C#
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
EAN-13 Supplement 5 Scanner In VB.NET
Using Barcode recognizer for .NET framework Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Similarly, both ProjectResource and ResourceAssignment have a Role property, allowing the role of the resource on the project to be changed. When that value is changed, it must be validated. Of course, this is handled by implementing a rule method conforming to the RuleHandler delegate defined by CSLA .NET. This is common behavior, so it is implemented in Assignment: Public Function ValidRole( _ ByVal target As Object, ByVal e As RuleArgs) As Boolean Dim role As Integer = CType(target, IHoldRoles).Role If RoleList.GetList.ContainsKey(role) Then Return True Else e.Description = "Role must be in RoleList" Return False End If End Function This method uses the IHoldRoles interface to retrieve the value of the Role property from the specified target object. This interface is defined like this: Friend Interface IHoldRoles Property Role() As Integer End Interface Notice that the interface is Friend in scope. It is only used within this assembly by the ValidRole() method, so there s no need to expose it as a public interface. Since both ProjectResource and ResourceAssignment implement this interface, the ValidRole() method has strongly typed access to the Role property on both objects. Using the retrieved role value, the RoleList collection is asked whether it contains an entry with that value as a key. If it does, then the role is valid; otherwise, it is not valid, so e.Description is set to indicate the nature of the problem and False is returned as a result. The RoleList object automatically caches the list of roles, so only the first call to GetList() by the application goes to the database, and subsequent calls are handled from the in-memory cache.
QR Code Reader In .NET
Using Barcode decoder for .NET framework Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Reading EAN13 In .NET
Using Barcode decoder for .NET framework Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Data Access
Recognizing Data Matrix ECC200 In .NET Framework
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
ANSI/AIM Code 39 Reader In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
The Assignment class also implements the data access behaviors common between both ProjectResource and ResourceAssignment. The AddAssignment() and UpdateAssignment() methods are very similar, in that they both create a SqlCommand object and then call a DoAddUpdate() helper method. Here s the UpdateAssignment() method:
CHAPTER 8 s BUSINESS OBJECT IMPLEMENTATION
Public Function UpdateAssignment(ByVal cn As SqlConnection, _ ByVal projectId As Guid, ByVal resourceId As Integer, _ ByVal assigned As SmartDate, ByVal newRole As Integer, _ ByVal timestamp() As Byte) As Byte() Using cm As SqlCommand = cn.CreateCommand() cm.CommandText = "updateAssignment" cm.Parameters.AddWithValue("@lastChanged", timestamp) Return DoAddUpdate( _ cm, projectId, resourceId, assigned, newRole) End Using End Function The only differences between UpdateAssignment() and AddAssignment() are the name of the stored procedure to be called and the fact that AddAssignment() doesn t add a timestamp parameter to the SqlCommand object. The timestamp value is only needed for updates to deal with optimistic concurrency. All the real work occurs in DoAddUpdate(): Private ByVal ByVal ByVal Function DoAddUpdate(ByVal cm As SqlCommand, _ projectId As Guid, ByVal resourceId As Integer, _ assigned As SmartDate, _ newRole As Integer) As Byte()
cm.CommandType = CommandType.StoredProcedure cm.Parameters.AddWithValue("@projectId", projectId) cm.Parameters.AddWithValue("@resourceId", resourceId) cm.Parameters.AddWithValue("@assigned", assigned.DBValue) cm.Parameters.AddWithValue("@role", newRole) Dim param As New SqlParameter("@newLastChanged", SqlDbType.Timestamp) param.Direction = ParameterDirection.Output cm.Parameters.Add(param) cm.ExecuteNonQuery() Return CType(cm.Parameters("@newLastChanged").Value, Byte()) End Function This method loads the parameters into the SqlCommand object and then executes it to call the proper stored procedure. Both the addAssignment and updateAssignment stored procedures were implemented in 6 to return the updated timestamp value for the row. That value is returned as an output parameter so the business object can store the new value. The Assignment class illustrates how to normalize behavior through collaboration, helping to ensure that a given behavior is only implemented once within the business layer.
Copyright © OnBarcode.com . All rights reserved.