WebMapLocation1.DistanceTo empty!

salve a tutti, ho il problema che non vengono calcolate le distanze in modo randomico, mi date un idea di dove sbaglio?

Hello everyone, I have the problem that distances are computed in random way, you give me an idea where I’m wrong?

  dim s as String = self.SearchField1.Text
  
  if s = "" then return
  
  if wml = nil then
    wml = new WebMapLocation ' propriet
    wml1 = new WebMapLocation ' propriet
  else
    self.MapViewer1.RemoveLocation(wml)
    self.MapViewer1.RemoveLocation(wml1)
  end if
  
  try
    
    wml = new WebMapLocation
    wml1 = new WebMapLocation
    
    wml.Address = s
    wml1.Address = self.TextField5.Text
    
    
    if wml.Address <> "" Then
      self.TextField1.Text = wml.Address
      self.TextField2.Text = wml.Latitude.ToText
      self.TextField3.Text = wml.Longitude.ToText
      self.TextField4.Text = "Distanza da " + self.TextField5.Text + " " + wml.DistanceTo(wml1).ToText + " km"
      self.TextField7.Text = str(TextField6.Text.Val * wml.DistanceTo(wml1) )
      self.TextField10.Text = str( TextField7.Text.Val / TextField8.Text.Val )
    end if
    
    self.MapViewer1.GoToLocation(wml)
    self.MapViewer1.AddLocation(wml)
    self.MapViewer1.AddLocation(wml1)
    
  Catch
    MsgBox "Error location"
    return
  end try

wml.DistanceTo(wml1) = 0 ?

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