virtualizingstackpanel

问题 Background I have a custom control that inherits from a TreeView and is modified to display in a data grid style. The problem I am seeing is with performance when expanding the tree. This is common from my research with Tree Views. Upon inspection with the WPF Performance tools I noticed that the ItemsPresenter class is using a regular Stack Panel instead of a Virtualizing Stack Panel. Here is the section of code where the ScrollContentPresenter is used (showing in image).

问题 I know that DataGrid supports virtualization, so it creates grid cells only for visible rows. However, this seems to work only if the DataGrid is constrained in size. In my scenario, a DataGrid is placed inside a scroll-viewer, like so <ScrollViever> <StackPanel> <more elements .../> <DataGrid ... /> <more elements .../> </StackPanel> </ScrollViever> This seems to break virtualization. In cases where the DataGrid should display a large number of items, the visual tree becomes very very large,

问题 I need to create a wrap panel with my facebook friends, meaning the itemcount is over 400, and it takes 5-10 seconds for all the items to load. <ListBox.ItemsPanel> <ItemsPanelTemplate> <toolkit:WrapPanel/> </ItemsPanelTemplate> </ListBox.ItemsPanel> This code would be good, but it puts all the elements in 1 Row ...: <ListBox.ItemsPanel> <ItemsPanelTemplate> <VirtualizingStackPanel Orientation="Horizontal"/> </ItemsPanelTemplate> </ListBox.ItemsPanel> Any ideas how to add item wraping to

问题 I have a ItemsControl which displays its items in a ScrollViewer , and does virtualisation. I am trying to scroll that ScrollViewer to an (offscreen, hence virtualised) item it contains. However, since the item is virtualised, it doesn't really exist on the screen and has no position (IIUC). I have tried BringIntoView on the child element, but it doesn't scroll into view. I have also tried manually doing it with TransformToAncestor , TransformBounds and ScrollToVerticalOffset , but

问题 I have an Itemscontrol using a VirtualizingStackPanel to display a huge (and growing) list of items: <ItemsControl Grid.Row="1" Name="ConversationItemsControl" VirtualizingStackPanel.VirtualizationMode="Recycling"> <ItemsControl.ItemsPanel> <ItemsPanelTemplate> <VirtualizingStackPanel Orientation="Vertical" /> </ItemsPanelTemplate> </ItemsControl.ItemsPanel> <ItemsControl.Template> <ControlTemplate TargetType="ItemsControl"> <ScrollViewer> <ItemsPresenter /> </ScrollViewer> </ControlTemplate>

问题 I've kind of coded myself into a pickle on this one. I am writing a custom WPF control which is similar to the TreeListView described in This MSDN article as well as many other places on the net. A pretty big pile of this thing is custom at this point, and it's meeting my goals fairly well, except on the virtualization front. My overriden TreeView and TreeViewItem templates both use VirtualizingStackPanel s to present their items, and I've verified that all of this is getting created as

问题 So, it looks really silly to have a chrome-less collection if the items are getting cut/cropped at the end of the scroll region. I want to create a virtualizing panel for collections (ItemsControl/ListBox) that only draws whole items, never pieces of items. For example: ______________ | | |______________| ______________ | | |______________| ______________ | | I don't want the 3rd partial container to be displayed unless there is room for the WHOLE item/container to be displayed. In the

问题 I want to add a header to my ListBoxes and I do this by using a template. The problem is that if I extend the ListBox's template it seems that the listbox's virtualizingstackpanel doesn't work anymore as expected: it loads all content before I can scroll it. I found some relevant questions in stackoverflow like this (VirtualizingStackPanel stops working when overriding the default control template for ScrollViewer) but the solution given there cannot be applied to WP7: I can't find the

问题 What is the difference between a stackpanel and a virtualizingstackpanel in WPF? 回答1: A VirtualizingStackPanel can offer performance benefits when working with very large collections. It does so by only rendering and processing a subset of the data which is visible to the user vs. processing the entire list of data. By creating only UI elements for the visible items, this can greatly reduce the amount of work it has to do. This is really only handy though if You are data binding non-UI

问题 I'm using ListBox which has VirtualizingStackPanel , which is said to support UI virtualizing by default. However, when I set my listStudent (of type ObservableCollection , and have 5 Students in it) as ItemsSource for my Listbox . Then whenever user scroll to the end, I add another 5 Students to my listStudent (and of course UI is notified). But I see that memory consumed keep increased. There's no different from StackPanel in term of memory How UI virtualization work? How to keep memory low