Visual Basic

Michael Schäuble wrote:

I'd like to understand where the problem arises. Could anyone of you tell me what's wrong in the (automatic) translation of the Lambda expression?

Bastard Programmer from Hell

Michael Schäuble wrote:

I'm afraid I don't understand what you mean

	AddHandler worker.ProgressChanged, AddressOf ProgressChanged

	worker.RunWorkerAsync()
	Console.Read()
End Sub
Public Sub ProgressChanged(sender As Object, e As System.ComponentModel.ProgressChangedEventArgs)
	' make sure the figure is written to the
	' same point on screen each time
	Console.SetCursorPosition(1, 0)
	Console.Write(e.ProgressPercentage)
End Sub

Bastard Programmer from Hell

Public Sub TestProgressReporting()
    worker = New BackgroundWorker()
    worker.WorkerReportsProgress = True

    AddHandler worker.DoWork, AddressOf DoWork
    AddHandler worker.ProgressChanged, AddressOf ProgressChanged

    worker.RunWorkerAsync()
    Console.Read()
End Sub

Private Sub DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs)
    Dim items(999) As Integer
    items.WithProgressReporting(AddressOf ReportProgress)   ' simulate some real work
End Sub

Private Function ReportProgress() As Integer
    worker.ReportProgress(progress).ForEach(Function(item) Thread.Sleep(10))
End Function

Private Sub ProgressChanged(ByVal sender As Object, ByVal e As ProgressChangedEventArgs)
    'worker.ReportProgress()
    ' make sure the figure is written to the
    ' same point on screen each time
    Console.SetCursorPosition(1, 0)
    Console.Write(e.ProgressPercentage)
End Sub

Michael Schäuble wrote:

In order to avoid problems with conversion of c# 'yield' operator, I put the extensions into a DLL and set a reference to that.

items
    .WithProgressReporting(progress => worker.ReportProgress(progress))
    .ForEach(item => Thread.Sleep(10)); // simulate some real work

Eddy Vluggen wrote:

How did you resolve the fact that VB.NET lacks a "yield return" statement?

items.WithProgressReporting(sub(progress) worker.ReportProgress(progress) end sub).forEach(function(item) thread.Sleep(10)))

items.WithProgressReporting(Sub(progress) worker.ReportProgress(progress)).ForEach(Sub(item) Thread.Sleep(10))

items.WithProgressReporting(Function(progress)
worker.ReportProgress(progress)).ForEach(Function(item) Thread.Sleep(10)) ' simulate some real work

items.WithProgressReporting(Function(progress) _
worker.ReportProgress(progress)).ToList.ForEach(Function(item) Thread.Sleep(10)) ' simulate some real work

items.WithProgressReporting(Sub(progress) worker.ReportProgress(progress)).ForEach(Sub(item) Thread.Sleep(10))

Class Program
    Shared worker As BackgroundWorker
    Public Shared Sub Main() 'ByVal args As String())
        worker = New BackgroundWorker()
        worker.WorkerReportsProgress = True
        AddHandler worker.DoWork, AddressOf DoWork
        AddHandler worker.ProgressChanged, AddressOf ProgressChanged
        worker.RunWorkerAsync()
        Console.Read()
    End Sub

    Private Shared Sub DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs)
        Dim items = Enumerable.Range(1, 1000)
        items.WithProgressReporting(AddressOf ReportProgress).ForEach(AddressOf DoSleep)
    End Sub
    Private Shared Sub ReportProgress(ByVal progress As Integer)
        worker.ReportProgress(progress)
    End Sub
    Private Shared Sub DoSleep(ByVal item As Integer)
        Thread.Sleep(10)
    End Sub
    Private Shared Sub ProgressChanged(ByVal sender As Object, ByVal e As ProgressChangedEventArgs)
        Console.SetCursorPosition(1, 0)
        Console.Write(e.ProgressPercentage)
    End Sub
End Class

items.WithProgressReporting(Sub(progress) worker.ReportProgress(progress)).ForEach(Sub(item) Thread.Sleep(10))

Dim items As IEnumerable(Of Integer) = Enumerable.Range(1, 1000)

Michael Schäuble wrote:

I had to change the definition of 'items'

ForEach(Sub(item) Thread.Sleep(10))

items.WithProgressReporting(Sub(progress) worker.ReportProgress(progress)).ForEach(Sub(item) Thread.Sleep(10))