Timer in Visual Basic

Question

What is the code for a timer in UWP Visual Basic ?

I am having issues implementing the information at https://learn.microsoft.com/en-us/windows/uwp/threading-async/use-a-timer-to-submit-a-work-item

I only need to launch the timer at a certain point of my app and run a procedure when the timer reaches a given elapsed time.

Thanks.

Answer 1

Hi, try following MVVM demo:

XAML:

<Page
    x:Class="UWP10App1VB.Page18"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:UWP10App1VB.UwpApp18"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
  <Page.DataContext>
    <local:ViewModel/>
  </Page.DataContext>
  <StackPanel>
    <Button Content="Start Timer" Command="{Binding Cmd}"/>
    <TextBlock Text="{Binding Info}"/>
  </StackPanel>
</Page>

ViewModel:

Namespace UwpApp18

  Public Class ViewModel
    Implements INotifyPropertyChanged

    Private _info As String
    Public Property Info As String
      Get
        Return Me._info
      End Get
      Set(value As String)
        Me._info = value
        OnPropertyChanged()
      End Set
    End Property

    Public Property Cmd As ICommand = New RelayCommand(AddressOf CmdExec)

    Private Sub CmdExec(obj As Object)
      Dim sc = SynchronizationContext.Current
      Info = "Timer will be startet"
      Dim DelayTimer = ThreadPoolTimer.CreateTimer(Sub(source)
                                                     ' do work
                                                     sc.Post(New SendOrPostCallback(Sub(state)
                                                                                      Info = "Timer ended"
                                                                                    End Sub), Nothing)
                                                   End Sub, TimeSpan.FromMinutes(1))
    End Sub

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
    Friend Sub OnPropertyChanged(<CallerMemberName> Optional propName As String = "")
      RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propName))
    End Sub
  End Class

End Namespace