Understanding Iterators, Part 2: Listing 3
The Visual Basic iterator property.
Public ReadOnly Iterator Property CoursesIteratorProperty(CategoryName As String) As IEnumerable(Of CourseWithModules)
Get
Dim iL As New IteratorsDemo.IteratorsLayer
Dim svcUri As Uri = New Uri("http://www.pluralsight-training.net/odata/")
Dim provider = New PluralsightService.CourseProvider(svcUri)
Dim courses = iL.GetCoursesForCategory(CategoryName)
For Each course In courses
Dim CoursesIterator = New CourseWithModules _
With {.Course = course, .Modules = iL.GetModulesForCourse(course.Name)}
Yield CoursesIterator
Next
End Get
End Property
Public Sub CategoryClickProperty(CategoryName As String)
lstCoursesAndModules.Items.Clear()
Dim courseCount = 0
Dim moduleCount = 0
For Each item In CoursesIteratorProperty(CategoryName)
lstCoursesAndModules.Items.Add(String.Empty)
Dim CourseLine = String.Format(" {0} ({1})", item.Course.Title, item.Course.Name)
lstCoursesAndModules.Items.Add(CourseLine)
courseCount += 1
For Each moduleItem In item.Modules
Dim ModuleLine = String.Format(" {0} ({1})", moduleItem.Title, moduleItem.VideoLength)
lstCoursesAndModules.Items.Add(ModuleLine)
moduleCount += 1
Next
Application.DoEvents()
Next
Dim header = String.Format("There are {0} Courses With {1} Modules For Category {2}", courseCount, moduleCount, CategoryName)
lstCoursesAndModules.Items.Insert(0, header)
End Sub
About the Author
Joe Kunk is a Microsoft MVP in Visual Basic, three-time president of the Greater Lansing User Group for .NET, and developer for Dart Container Corporation of Mason, Michigan. He's been developing software for over 30 years and has worked in the education, government, financial and manufacturing industries. Kunk's co-authored the book "Professional DevExpress ASP.NET Controls" (Wrox Programmer to Programmer, 2009). He can be reached via email at [email protected].