C# need to programmatically switch the mode between day and night

[Nezar]

Good afternoon.
Help with C# code
You need to programmatically switch the mode between day and night.
According to the documentation, the byDayNightFilterType parameter is responsible for this

I try to do this - but the mode does not change ((
NET_DVR_DAYNIGHT dayNightConfig = new NET_DVR_DAYNIGHT();
dayNightConfig.byDayNightFilterType = 1; // Set night mode

Maybe something else needs to be added.
I'm not good at programming ((
Thank you!