I want to set the Text of a TextBlock in my StatusBar before making the user wait for a short moment while my program does a little bit of work.
Aparently, instead of doing a nice little function like this (which does not work):
Function Load(ByVal Id As Guid) As Thing
Cursor = Cursors.Wait
TextBlockStatus.Text = "Loading..."
TextBlockStatus.UpdateLayout()
Dim Found = From t In db.Thing _
Where t.Id = Id _
Select t
TextBlockStatus.Text = String.Empty
Cursor = Cursors.Arrow
Return Found
End Function
I have to instead use this monstrosity:
Private WithEvents LoadWorker As BackgroundWorker
Private Sub Window1_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded
InitializeLoadWorker()
End Sub
Private Sub InitializeLoadWorker()
LoadWorker = New BackgroundWorker
LoadWorker.WorkerSupportsCancellation = False
LoadWorker.WorkerReportsProgress = False
AddHandler LoadWorker.DoWork, AddressOf LoadBackgroundWorker_DoWork
AddHandler LoadWorker.RunWorkerCompleted, AddressOf LoadBackgroundWorker_RunWorkerCompleted
End Sub
Sub Load(ByVal Id As Guid)
Cursor = Cursors.Wait
LoadWorker.RunWorkerAsync(Argument)
End Sub
Private Sub LoadBackgroundWorker_DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs)
Dim Worker As BackgroundWorker = DirectCast(sender, BackgroundWorker)
Dim Id As Guid = DirectCast(e.Argument, Guid)
e.Result = From t In db.Thing _
Where t.Id = Id _
Select t
End Sub
Private Sub LoadBackgroundWorker_RunWorkerCompleted(ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs)
TextBlockStatus.Text = String.Empty
Cursor = Cursors.Arrow
Dim Found As Thing = DirectCast(e.Result, Thing)
'now do something with the found thing here instead of where Load() is called.'
End Sub
And the Load() Function is now a Sub!!
There must be a better way to handle such a simple situation. This doesn't need to be asynchronous.