TcHmiView

Behavior in the life cycle

A view control can behave differently during its life cycle. If you select the view file in the project tree, you can select the following settings:

Preload: Defines whether the file should be loaded and compiled during initialization to speed up later use. The default value False increases the speed of the initial loading process of the HMI, but can lead to a reduction in the loading speed of individual HMI pages on which many controls are instantiated. Memory consumption is also reduced because the pages are no longer in memory when they are not active.

KeepAlive: Defines whether the compilation result should be saved temporarily after the first use in order to speed up subsequent use. The default value is False. If this option is enabled, the controls are kept in the browser cache. This increases the loading speed of a single HMI page if it is called several times. The controls of a page are created when the page is accessed for the first time. They are retained when the page is exited. This only slightly increases memory consumption, since only those pages remain in memory that were enabled once.

Pages with KeepAlive are therefore kept in memory similar to Preload when they are no longer needed. In contrast, these pages are not loaded initially. This ensures fast loading of the entire application.

PreloadBindings: Defines whether bindings to controls in this file should be preloaded before the content is displayed in order to have correct values when displaying the content. Requires that Preload is enabled. The default value is False.

Please also note the background information on the life cycle for control development.