Layout.InValidateLayout Method Xamarin forms

Question

Hi,

Could anyone explain what Layout.InvalidateLayout Method does. It's being used in my project, but I am not sure what's the use of it and what does InValidateLayout() do.

It would be great if anyone could explain this with an example.

Thanks

Answer 1

Hello anonymous user,

Elements invalidate themselves by invoking the InvalidateMeasure method, generally when a property of the element changes that might result in a new size of the element. The Layout class also defines an InvalidateLayout method that has a similar purpose to the InvalidateMeasure method. The InvalidateLayout method should be invoked whenever a change is made that affects how the layout positions and sizes its children.

You could refer to the Invalidation part of this article at https://learn.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/layouts/custom#invalidation and this article at https://learn.microsoft.com/en-us/xamarin/xamarin-forms/creating-mobile-apps-xamarin-forms/summaries/chapter26#some-rules-for-coding-layouts

About sample, you could check https://learn.microsoft.com/en-us/samples/xamarin/xamarin-forms-samples/userinterface-customlayout-wraplayout

Best Regards,
Wenyan Zhang

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