SuspendLayout to Form and Control

zequion 446

In WPF I have a task that executes a function that loads about 150 titles into a DevExpress NavBar control and a ComboBox. The function takes a long time to finish and it seems that it is because the NavNar control takes a long time to render all the items on the screen. I need a way to do SuspendLayout to the Form and the Control. For the Form I use:

// SuspendLayout.
System.Windows.Threading.Dispatcher MyDispatcher = System.Windows.Threading.Dispatcher.CurrentDispatcher;

System.IDisposable MyThread_IDisposable = MyDispatcher.DisableProcessing();


// ResumeLayout.
MyThread_IDisposable.Dispose();

But it doesn't seem to do anything because the control is rendering the items on the screen. It's because the screen form is not locked. But I don't actually want to lock the form, just the control. I don't know of a way to do SuspendLayout to the control.

Hui Liu-MSFT 48,536 Reputation points Microsoft Vendor

2024-09-17T07:12:04+00:00
Hi,@zequion. Welcome to Microsoft Q&A.

In WPF, there's no direct equivalent to SuspendLayout and ResumeLayout as found in Windows Forms. you could try to achieve similar behavior by temporarily suspending rendering updates to the control, particularly the DevExpress NavBarControl, using strategies like virtualization, UI freezing, or deferred rendering.

1.Use BeginInit and EndInit for the Control

The BeginInit and EndInit methods allow you to pause rendering or initialization updates for WPF controls. You can use these to "suspend" and "resume" layout changes, particularly when you need to load many items into a control.

navBarControl.BeginInit(); // Load your 150 titles here. // Add all your items to the NavBarControl and ComboBox. // Resume layout and updates. navBarControl.EndInit();

2.Virtualization ensures that only the visible items are rendered, which greatly improves performance when dealing with a large number of items.

<ComboBox VirtualizingStackPanel.IsVirtualizing="True" VirtualizingStackPanel.VirtualizationMode="Recycling"> </ComboBox>

3.If you need to batch UI updates, you can defer the rendering of the UI using the Dispatcher and DispatcherPriority. This allows the UI to process background work before rendering changes:

Dispatcher.BeginInvoke(new Action(() => { // Load items to NavBarControl here. // This will batch the updates without blocking the UI. }), DispatcherPriority.Background);

For usage of third-party DevExpress controls, you can ask questions in the DevExpress forum.

1 answer

zequion 446 Reputation points

2024-09-17T23:14:49.2633333+00:00

I've been told that I can use the control's BeginInit() to add the items and not render them. How do I use this if the control has already been initialized and is displayed?
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