winrt-xaml – ScrollViewer.ChangeView返回false

<ScrollViewer VerticalSnapPointsAlignment="Near"
                          VerticalSnapPointsType="Mandatory"
                          VerticalScrollMode="Enabled"
                          VerticalScrollBarVisibility="Hidden"
                          ZoomMode="Disabled"
                          Width="400"
                          Height="400"
                          x:Name="MainFeatureScrollViewer"
                          ViewChanging="ScrollViewer_ViewChanging">
                <StackPanel x:Name="MainFeatureStackPanel" />
            </ScrollViewer>

当我像下面一样调用ChangeView时,它返回false并且没有任何反应.为什么这不起作用？

bool result = this.MainFeatureScrollViewer.ChangeView(null,400,null,true);