I am trying to get the render size of a region via the region manager. The reason for this is each time I add a view to the region I want to make sure it will visually fit, I can get the dimensions of the view I am about to add but I am struggling to find a way of getting the height of the region I am about to add to.
Obviously I want to stay away from the view behind code and accessing the UIElement for the region directly.
Any ideas?
Thanks for your time
I'd recommend against trying to do this at all. Instead, I would focus on making the region adaptable to being overfilled (automatic resizing, scrolling, tabs, etc).
There's a lot of unpredictable things that can happen here. For example, there are some controls whose views are determined by their container. The true size of the view that you want to add to the region will not be known until it's actually added to the region, so making this decision will be non-trivial.
I know this doesn't directly answer your question, but hopefully it will be helpful regardless.
You can use
_regionManager.Regions[regionName].Views.ElementAtOrDefault(0);
to get the current view of the region you want to use.
Then you can check the DesiredSize property of that view to see what the probable width and height is of that region.
I think this should work in normal usage.
The thing is there always needs to be a view in that region. If there isn't you might want to use a dummy view or so.
Related
RequestNavigate(uri) is nice when you want to navigate to region using a string and immediately make it the active view. But what if you want to add a region without activating it? Is there a way to do that with a string?
I have a view model that needs to add some views to a docking control dynamically. These views should not be activated when they are added. Adding a region using Region.Add works but I have to give it a type:
RegionManager.Regions[KnownRegionNames.DockingRegion].Add(typeof(MyView));
I feel like this violates some MVVM principals of making the ViewModel completely independent from views. It's not absolutely terrible since I can probably mock out the region manager in testing, but is there another way?
You'll have to somehow identify the view you want to add to your region, either by type or by string.
You can use the string to resolve it from the container (basically what the region manager does) and add the resolved view to the region.
You know, like in CCleaner app where main activity is on the left side of the app and the right side area is changeable fragment.
http://cache.filehippo.com/img/ex/3049__ccleaner1.png
How to do it? I imagine I could do it by putting all fragments in the same place and just change their visibility to show just 1 at the moment, but that would make the code a whole lot of mess.
I've done this in the past by using UserControls. It's worked nicely for things like choosing payment methods (cash, cc, cheque...).
There are a couple of options for changing the display, either have all the UserControls present on the form and hide or show them as required or have an empty placeholder panel and use a factory to construct the appropriate UserControl as needed. I've done both and it really depends on the complexity (and expected longevity and users) of the project as to which is appropriate.
Using a Model-View-Presenter pattern helped with managing all of this.
What you don't want to end up with is a massive switch statement that changes the visibility of dozens of manually positioned controls individually. I've seen it and that way lies madness.
I am new to WPF environment and I am experiencing some problems like if there are alots of things how do we manage them.for example I have three borders each of same size same location and they contains controls like textboxes etc etc we construct them sequentially but when it comes to edit we get in trouble modifying the border that is at bottom.
So in short how do we manage many controls on single page so that it remains easy to edit
Not sure I completely understand your concerns, but here are several point that make editing WPF UI pretty easy:
Correct usage of layout panels. If you will use approach with absolute positions for each control then it might become a nightmare to move or resize some of your controls. Correct layout (and panels such as DockPanel/StackPanel/etc) might help you a lot.
Incapsulating repeatable parts. WPF has a lot of feature to avoid repeating UI code. I'm talking mostly about Styles and Control templates at the moment. If you have your borders repeating through the entire window, maybe you should think on extracting this border as a ControlTemplate for ContentControl for example?
but I've found that encapsulating controls such as borders, textboxes etc in User Controls helps to keep things well managed (not to mention helps reduce code), similarly using a Resource Dictionary to store styles/animations is useful for very big projects (remember though that the local resources will take precedence when applied so remove them if they not in use)
furthermore, using Layout Panels such as Stacks,Grids and Dockpanels allows you to collapse User Controls when not needed or otherwise (also I've found that for some reason, Grids allow controls to overlap (when items are not correctly ordered in Grid Rows and Columns) which can lead to some elements not being seen in design.
Plan your layout properly and think through which Panels would be best for them, having to go back much later and change can be annoying (though admittedly it happens).
Also remember to use partial classes to properly structure your stuff, having to read through 1000+ lines of code to find something can be a nightmare.
We just ported our WinForms application to WPF.
However, performance decreased dramatically.
We have a User Interface which consists of about 200 UserControl.
Each UserControl is defined by a DataGrid (= 10 columns and 3-15 rows) as well as a Panel which hosts about 10 Buttons.
They are all hosted in a ScrollViewer.
(Please don't recommend to change the UI. I don't have any influence on that. The customer wants to be able to scroll to any of those UserControls.)
Since we ported the whole application to WPF the startup time increased by 100%. Using WinForms we experienced startup times of 15sec whereas now, we are struggeling with 30s.
Do you have any recommandations or ideas how to improve the loading time of a UI which consists of identical UserControl where simply each UserControl is bound to a different ViewModel? (Maybe some fast cloning of the UserControl instances or sth similar?)
I am using static Resources whereever possible.
I avoid Grids and Auto Sizing whereever possible.
Hope someone can share some thoughts on that one.
Thanks,
TH
First find out what is responsible for the time.
Maybe it's the controls, and maybe not. Often it's data structure.
I use the random-pause method.
My final solution is a custom Virtual Panel which supports items of dynamic height.
See http://rhnatiuk.wordpress.com/2006/12/13/implementing-a-virtualized-panel-in-wpf/ on how to create virtual panels.
My UserControls support two states:
- Initial
- Loaded
When the application is in idle the virtual Panel asks the Controls to change to the "Loaded" state. This loads the expensive UserControl.
Like that everything is lazy loaded and as soon as the user stops scrolling the visible items are loaded.
Maybe that helps others that are in the same sitaution.
TH
Try only to create the controls which are visible at the time, use lazy loading.
Maybe SnapsToDevicePixels=true can also help a little bit.
Guys, I thought about the following implementation. If anyone has concerns please let me know:
I will implement my own virtualizing "StackPanel" which supports smooth scrolling.
For the moment we assume that the height of my UserControls is fixed. One page could possibly hold 5 UserControls.
I will then go ahead and cache the preceding as well as the proceeding page:
In memory I will always hold 15 UserControls.
The content of the ScrollViewer is a Canvas.
Locations of my UserControls are adjusted by setting Canvas.Top.
Let's say the current situation is the following:
User has scrolled to page 2.
That means UserControl 5-9 is visible. Now the user scrolls down.
As soon as UserControl 5 becomes invisible I take the UC of the top (in this case UserControl 0), change its ViewModel and adjust its Canvas.Top so that it now is the Control which is at the End of the ControlCollection.
If the user scrolls any further I take UC 1, change its ViewModel and adjust its Canvas.Top.
And so on.
Furthermore I will set Canvas.Height manually so that the ScrollViewer represents the ScrollBars in a correct way.
I hope my explanation is understandable :)
What do you think?
BR,
TH
I remember reading something about how each instance of a UserControl loads the resource dictionary. So if you have as many of these as you describe it can take a while to load those.
Unfortunately I can't find the link I remember, but here is one that might help:
http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/c9b6aa9f-5a97-428c-8009-5cda432b820c
Another thing to try is to not use UserControls and instead use a DataTemplate to build your datagrids and buttons. Or make a custom control template for the datagrid that includes the buttons. Either one might be faster.
Hope this helps.
My app has many controls on its surface, and more are added dynamically at runtime.
Although i am using tabs to limit the number of controls shown, and double-buffering too, it still flickers and stutters when it has to redraw (resize, maximize, etc).
What are your tips and tricks to improve WinForms app performance?
I know of two things you can do but they don't always apply to all situations.
You're going to get better performance if you're using absolute positioning for each control (myNewlyCreatedButton.Location.X/Y) as opposed to using a flow layout panel or a table layout panel. WinForms has to do a lot less math trying to figure out where controls should be placed.
If there is a single operation in which you're adding/removing/modifying a lot of controls, call "SuspendLayout()" on the container of the affected controls (whether it is a panel or the whole form), and when you're done with your work call "ResumeLayout()" on the same panel. If you don't, the form will have to do a layout pass each and every time you add/remove/modify a control, which cost a lot more time. see: http://msdn.microsoft.com/en-us/library/system.windows.forms.control.suspendlayout(VS.80).aspx
Although, I'm not sure how these approaches could apply when resizing a window.
Although more general than some of the other tips, here is mine:
When using a large number of "items", try to avoid creating a control for each one of them, rather reuse the controls. For example if you have 10 000 items, each corresponding to a button, it is very easy to (programatically) create a 10 000 buttons and wire up their event handlers, such that when you enter in the event handler, you know exactly which element you must work on. However it is much more efficient if you create, lets say, 500 buttons (because you know that only 500 buttons will be visible on the screen at any one time) and introduce a "mapping layer" between the buttons and the items, which dynamically reassigns the buttons to different items every time the user does something which would result in changing the set of buttons which should be visible (like moving a scrollbar for example).
Although, I'm not sure how these approaches could apply when resizing a window.
Handle the ResizeBegin and ResizeEnd events to call SuspendLayout() and ResumeLayout(). These events are only on the System.Windows.Form class (although I wish they were also on Control).
Are you making good use of SuspendLayout() and ResumeLayout()?
http://msdn.microsoft.com/en-us/library/system.windows.forms.control.suspendlayout(VS.80).aspx