public void SetInitialIntensityProperty(LightType lightType)
{
    InitialIntensity initialIntensity = lightType.GetInitialIntensity();
    if (initialIntensity is InitialFluxIntensity)
    {
        InitialFluxIntensity fluxIntensity = initialIntensity as InitialFluxIntensity;
        double fluxValue = fluxIntensity.Flux;

        // Set new value for Flux proeprty and set modified InitialIntensity to LightType.
        fluxIntensity.Flux = 34.50;
        lightType.SetInitialIntensity(fluxIntensity);

        // Create a InitialWattageIntensity and set it to LightType.
        InitialWattageIntensity wattageIntensity = new InitialWattageIntensity(25.57, 130.89);
        lightType.SetInitialIntensity(wattageIntensity);
    }
}

Public Sub SetInitialIntensityProperty(lightType As LightType)
   Dim initialIntensity As InitialIntensity = lightType.GetInitialIntensity()
   If TypeOf initialIntensity Is InitialFluxIntensity Then
      Dim fluxIntensity As InitialFluxIntensity = TryCast(initialIntensity, InitialFluxIntensity)
      Dim fluxValue As Double = fluxIntensity.Flux

      ' Set new value for Flux proeprty and set modified InitialIntensity to LightType.
      fluxIntensity.Flux = 34.5
      lightType.SetInitialIntensity(fluxIntensity)

      ' Create a InitialWattageIntensity and set it to LightType.
      Dim wattageIntensity As New InitialWattageIntensity(25.57, 130.89)
      lightType.SetInitialIntensity(wattageIntensity)
   End If
End Sub