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Abdurrahman Oguz
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How to determine UltraListView UIElement partially in view
posted

Hi,

I have a custom creation filter on ultralistview to load image on demand. when item is fully visible its image will load.,

it works good but in thumbnail view if just 1 px of item is out of scope it does not load image.

 

is there any way to determine partially viewed items or one more line before and one more line after from viewed items at least.

here a part of my custom creation filter...

Public Sub AfterCreateChildElements(parent As UIElement) Implements IUIElementCreationFilter.AfterCreateChildElements

     If TypeOf parent Is UltraListViewItemUIElement Then

         Dim item As UltraListViewItemUIElement = DirectCast(parent, UltraListViewItemUIElement)

         If item.Item.Appearance.Image Is Nothing AndAlso item.IsFullyVisible Then

             item.Item.Appearance.Image = Me.GetThumbnail(item.Item.SubItems("FilePath").Value.ToString())

         End If

     End If

End Sub

Public Function BeforeCreateChildElements(parent As UIElement) As Boolean Implements IUIElementCreationFilter.BeforeCreateChildElements

     Return False

End Function

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  • 21795
    Offline posted

    Hello Abdurrahmanoguz,

    Yes, you can achieve this. Each item UIElement is nested in UltraListViewItemContainerUIElement. One possible solution could be to check the rectangle of item UIElement against the one of the container UIElement. You can use code like this:

    Dim containerElement = item.Parent
    Dim margin As Integer = 1
    Dim isTopCut = containerElement.Rect.Top - item.Rect.Top < margin
    Dim isLeftCut = containerElement.Rect.Left - item.Rect.Left < margin
    Dim isRightCut = containerElement.Rect.Right - item.Rect.Right < margin
    Dim isBottomCut = containerElement.Rect.Bottom - item.Rect.Bottom < margin
    Dim isFullyVisible = isTopCut OrElse isLeftCut OrElse isRightCut OrElse isBottomCut

    Please let me know if you have any additional questions.

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