CODEWITHSUNDEEP
c#wpfcustom-controlsrenderinginvalidation
Spook
Spook

Reputation: 25927

Does InvalidateVisual works in a lazy way?

If I call InvalidateVisual in my custom WPF control, when does the actual layout evaluation and rendering process happen?

Immediately or - similarly as in WinForms - when I finish my processing?

Upvotes: 4

Views: 5132

Answers (1)

user128300
user128300

Reputation:

The online help answers your question:

Online help for InvalidateVisual:

This method calls InvalidateArrange internally.

Online help for InvalidateArrange:

Invalidates the arrange state (layout) for the element. After the invalidation, the element will have its layout updated, which will occur asynchronously unless subsequently forced by UpdateLayout.

In other words: InvalidateVisual does not have an effect immediately; it waits until your current code has finished (unless you have calls to UpdateLayout).

You also can look at Microsoft's reference source: http://referencesource.microsoft.com/#q=UIElement.InvalidateArrange . You will see that InvalidateArrange() does not call any blocking code; it returns immediately.

Upvotes: 5

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