Mindscape Blog » Blog Archive » Using LightSpeed from VB

Using LightSpeed from VB

A nice feature of .NET is the great interop between components written in different languages. LightSpeed is no exception and can be used just as easily from VB.NET. Here is a simple example modeling the concept of a Task that has an associated Status.

First we declare the Status entity. The VB code is almost exactly the same as it’s C# equivalent – with one minor difference; we need to manually call the LightSpeed Initialize method from our constructor. This is due to a difference in when field initializers are run in VB. In VB field initializers are run after base class constructors. :-S

' Status Entity
 
Imports Mindscape.LightSpeed
Imports Mindscape.LightSpeed.Validation
 
Public Class Status
  Inherits Entity(Of Integer)
 
  <ValidatePresence()> _
  Private _statusName As String
 
  Private ReadOnly _tasks As New EntityCollection(Of Task)()
 
  ' Need to explicitly initialize in VB
  Public Sub New()
    MyBase.New(False)
    Initialize()
  End Sub
 
  Public Property StatusName() As String
    Get
      Return _statusName
    End Get
    Set(ByVal value As String)
      [Set](_statusName, value, "StatusName")
    End Set
  End Property
 
  Public ReadOnly Property Tasks() As EntityCollection(Of Task)
    Get
      Return [Get](_tasks)
    End Get
  End Property
 
End Class

Next we can create the Task model:

' Task Entity
 
Imports Mindscape.LightSpeed
 
Public Class Task
  Inherits Entity(Of Integer)
 
  Private _statusId As Integer
 
  Private ReadOnly _status As New EntityHolder(Of Status)()
 
  ' Need to explicitly initialize in VB
  Public Sub New()
    MyBase.New(False)
    Initialize()
  End Sub
 
  Public Property Status() As Status
    Get
      Return [Get](_status)
    End Get
    Set(ByVal value As Status)
      [Set](_status, value)
    End Set
  End Property
 
  Public Property StatusId() As Integer
    Get
      Return _statusId
    End Get
    Set(ByVal value As Integer)
      [Set](_statusId, value, "StatusId")
    End Set
  End Property
 
End Class

Our database schema will of course look something like this:

 
CREATE TABLE STATUS
(
  Id INT NOT NULL PRIMARY KEY IDENTITY,
  StatusName NVARCHAR(32) NOT NULL
)
 
CREATE TABLE Task
(
  Id INT NOT NULL PRIMARY KEY IDENTITY,
  StatusId INT NOT NULL FOREIGN KEY REFERENCES STATUS(Id)
)
 
GO
 
INSERT INTO STATUS (StatusName) VALUES ('Completed')
INSERT INTO Task(StatusId) VALUES (SCOPE_IDENTITY())
INSERT INTO STATUS (StatusName) VALUES ('Pending')
INSERT INTO Task(StatusId) VALUES (SCOPE_IDENTITY())

Now we can go ahead and start using our model – In C# unit tests this time :-)

namespace Tests
{
  [TestFixture]
  public class UnitTests
  {
    // initialize LightSpeed
 
    static UnitTests()
    {
      LightSpeedContext.ConnectionString
        = @"Data Source=ORMapper;Initial Catalog=LightSpeedVBExample;Integrated Security=SSPI";
 
      LightSpeedContext.IdentityMethod = IdentityMethod.IdentityColumn;
      LightSpeedContext.Logger = new ConsoleLogger();
    }
 
    // transactional tests - all database changes rolled back after test
 
    private TransactionScope _transactionScope;
 
    [SetUp]
    public void SetUp()
    {
      _transactionScope = new TransactionScope();
    }
 
    [TearDown]
    public void TearDown()
    {
      Repository.CompleteUnitOfWork(false);
 
      _transactionScope.Dispose();
    }
 
    // unit tests against model
 
    [Test]
    public void FindTasks()
    {
      IList<Task> tasks = Repository.Find<Task>();
 
      Assert.AreEqual(2, tasks.Count);
 
      Task task = tasks[0];
 
      Assert.IsNotNull(task);
      Assert.IsNotNull(task.Status);
    }
 
    [Test]
    public void FindStatuses()
    {
      IList<Status> statuses = Repository.Find<Status>();
 
      Assert.AreEqual(2, statuses.Count);
 
      Status status = statuses[0];
 
      Assert.IsNotNull(status);
      Assert.AreEqual(1, status.Tasks.Count);
    }
 
    [Test]
    public void NewTask()
    {
      Task task = new Task();
      task.Status = Repository.FindOne<Status>(
        Entity.Attribute("StatusName") == "Pending");
 
      Repository.Add(task);
      Repository.SaveChanges();
    }
 
    [Test]
    public void NewStatus()
    {
      Status status = new Status();
      status.StatusName = "New Status";
 
      Repository.Add(status);
      Repository.SaveChanges();
    }
 
    [Test]
    public void UpdateTask()
    {
      IList<Task> tasks = Repository.Find<Task>();
 
      Task task = tasks[1];
 
      Assert.AreEqual("Pending", task.Status.StatusName);
 
      task.Status = Repository.FindOne<Status>(
        Entity.Attribute("StatusName") == "Completed");
 
      Repository.SaveChanges();
    }
 
    [Test]
    public void UpdateStatus()
    {
      IList<Status> statuses = Repository.Find<Status>();
 
      Status status = statuses[0];
 
      Assert.AreEqual("Completed", status.StatusName);
 
      status.StatusName = "Complete!";
 
      Repository.SaveChanges();
    }
 
    [Test]
    public void DeleteTask()
    {
      IList<Task> tasks = Repository.Find<Task>();
 
      Task task = tasks[1];
 
      Repository.Remove(task);
      Repository.SaveChanges();
    }
 
    [Test]
    public void DeleteStatus()
    {
      IList<Status> statuses = Repository.Find<Status>();
 
      Status status = statuses[0];
 
      Repository.Remove(status);
      Repository.SaveChanges();
    }
  }
}

Add your comments
Author icon

Posted by Andrew Peters on 22 August 2007

Subscribe to our blog

Join us on Facebook

Using LightSpeed from VB

Leave a Reply

Subscribe

Categories

Archives