I have an application for the windows store that I need to make emulate the tabs like Internet Explorer. The problem is that I have one control and it won't load into both the AppBar and the main view.
Is there a way to setup the CacheMode in the constructor of the control and then pull a bitmap from the BitmapCache and load that in the tab view in the AppBar? Or am I going about this the wrong way. I don't want to use two different controls due to it being a hack I want this to work with one control.
I am writing this application in C# and XAML.
Any help is appreciated.
A control can only have one parent in all popular XAML technologies, so you can't put it in two places.
You can use RenderTargetBitmap to take a screenshot of a control and put it elsewhere in your layout, but there are plenty of problems with that
It uses additional memory to store the bitmap
You need to figure out when to take that screenshot - typically after all images load and after every layout or content update.
A bitmap is not interactive.
Your best bet might really be to have two copies of the same control. You can create a UserControl to encapsulate any functionality and properties and reuse that control in multiple places easily. If you reference an image by URI - the platform should automatically share the resources for the image used in multiple controls.
Related
In my UWP app, my control options are User Control and Templated Control. My understanding of a User Control is KIND OF clear at this point.
I was told that a Custom Control's style/template is only instantiated in memory once, and that this only happens at the time the control is first used. That's what I want since I know the control I am creating will be used in a ListView.
In the book, XAML Unleashed, however, the author creates his Custom Control by starting with a User Control, and then simply changing it's base class. The thing is that the control he created calls InitializeComponent(). I hear that this type of class uses more memory because it is re-instatiated for each item in the ListView.
Also, I never thought that Custom Controls used the InitializeComponent() method. I thought there was simply a call to this.DefaultStyleKey = typeof(MyClass); in the constructor. What gives? I am confused on what is what...
And last, why is the style/template of the Templated Control placed in the global Generic.xaml file, instead of its own separate file (i.e., xaml file and a code-behind file pair)? If the control is supposed to be custom and "portable", then shouldn't it be totally separate from other code? I haven't found a single article explains any of these things in detail on any level.
This is something most people get wrong so I'll try to clarify a few things for you.
Memory
The whole memory thing, it's all in the Visual Tree. When you instantiate any control, whether templated or UserControl, you will use up memory with every instance because in both cases you are creating a full copy of the visual components in the template.
The templated control will create a copy from the ControlTemplate while the UserControl parses the XAML file when InitializeComponent() is called.
Memory usage will be the same if you create 100 templated controls or 100 user controls if their content is the same.
Usage
Templated controls are best for situations where you're creating a single component, like a Button, Slider, MyStarRatingInput, etc. and you're giving the users of your control the ability to swap out the template with their own. It takes a lot more effort to do this properly than UserControls because the logic has to be template agnostic and your templates have to react properly with visual state changes.
A UserControl is best for layout or views, like forms, popups, screens, pages, etc. You will not give someone the freedom to tamper with the content of your view. You may expose a few public/dependency properties if some views are reusable in a small way, but generally they are set in stone.
Generic.xaml
I honestly don't have an answer for this. Microsoft should've allowed multiple resource dictionaries to enable cleaner partitioning of control templates. Generic.xaml is a reserved filename that referencing projects will look for as the root source of the base styles of your controls. You could reference other XAML files from Generic.xaml, but that's annoying and it bloats the root of your resource dictionary. For now, you're stuck with this method.
Recommendation
If you're sharing a control library, you would want to use templated controls as much as possible. If you're building controls, views, pages, etc for your current project and they're not meant for reuse, then use UserControls.
You can still create a UserControl in your control library if you plan on owning the template and forcing all users to accept your design.
I also recommend templated controls for items that you plan on instantiating a hundred times in a single view, like a ListView. You will see noticeable speed improvement if your template is preloaded into memory instead of parsing a XAML file on every instance.
I am working on a Win8 app destined for the Windows Store. Hurdles I am trying to overcome is how to deal with the different ways an app can be displayed.
Currently, my main pages is a LayoutAwarePage so it has logic to handle different visual states. However, my question is more how to make my page render differently depending on its state.
I thought, initially, that you basically created a layout for each state that the application supports. But it seems like the VisualStateManager portion of the XAML is just an area where you make piecemeal modifications to the design (hide an element, change an alignment).
I am working with a grid that has many columns and rows to organize my controls and it looks great in fullscreen. However, this doesn't work at all in the snapped state, as most of my controls become hidden off screen. I could certainly add a ScrollViewer control, but this is basically a hack and a usability nightmare for a user.
Thanks for any insight!
It might be that your app doesn't lend itself to snapped view. You are allowed to simply display a message / image that states this. Alternatively, consider just showing the columns that are most important.
The standard MS way seems to be to replace horizontal oriented controls with vertical ones - maybe a listview or something would look better. You'll probably find your code easier to read if you have one control for snapped and another for full screen.
Not exactly related to your question, but Blend works very well with XAML to allow you to manipulate the grid or show the relevant control.
Here is a very good guide from Jerry Nixon.
http://blog.jerrynixon.com/2012/12/walkthrough-implementing-snapview-in.html
I want to make a custom control with the Windows 8 API in C# so that it will run on an RT app distributed through the store.
I looked through what I can add to a project and found Templated Control and User Control. Both allow me to organize other controls and some logic into a new control for reusability.
But this isn't what I want. I want to be able to custom paint and create controls. I would be shocked if they removed this but am honestly uncertain if I can. I'm basically looking for what class to inherit from and what method / event to override to let me draw the control myself.
I found a way to use the Templated Control option that I wasn't aware of before. Essentially my custom control has a canvas that I 'paint' with objects (lines, images, etc.) by adding them as children and manipulating them in events.
This tutorial helped me figure out what I was doing.
I've seen other people say they created a rectangle and painted it with a special Brush, either a ImageBrush (where they drew an image in the background) or a DrawingBrush.
Hopefully one of these two approaches can help anyone looking for the same thing I was.
Im currently trying to create an application that will require 10+ different "pages" with different content and controls, and i need to switch back and forth between them on particular events.
What ive been doing, is just creating all the different sections in grids, and setting their visibility to collapsed, and then when i need to show them, just switch out the visible grid to the new one.
This has several drawbacks, im assuming its very poor from a coding standpoint, and this pretty much dis-allows me from using the designer at all. (i have no idea what performance implications it has, either)
on top of that, every time i switch to the new page, i need to reset all the components (textbox's etc) to their default states, as they dont get reset by becoming invisible :P
on to my question: i need a way to map out all the different pages, provide visually attractive transitions between them, and be able to use a designer to create them (and i dont mean designing it somewhere and then just copying the xaml)
I had looked around, and ran into SketchFlow and it seemed like the perfect solution, i could fade between pages and map everything on a flow chart easily, and then i realized it was only for app prototypes and i couldnt actually compile it as a normal application... and i needed to inherit from a custom Window class aswell.
is there something out there that allows me to do this? or how can i code this to work properly?
note: this ABSOLUTELY needs to stay within one window. i cant venture out into having 10+ different windows that pop up every time i need to change to something. as this happens very frequently
Split the separate sections in individual user controls. This would allow you to design each of them easily. Then on your form use code to create and load a new instance of particular user control that represents the section you need to show, and when transitioning, load the new section and unload the current. this would allow your form to stay relatively lightweight.
An alternative is to create a navigation application and split your sections into separate XAML view and use the standard navigation service to switch between them.
WPF Navigation Overview
Creating Navigation Applications video tutorial
You might wanna convert your "Pages" to usercontrols and use some transitions like mentioned in the below link to switch between controls
http://www.tanguay.info/web/index.php?pg=codeExamples&id=280
for more on using transitions look here
http://www.japf.fr/2009/04/adding-transitions-to-a-mvvm-based-dialog/
or
http://www.japf.fr/2008/07/8/comment-page-1/
i have a winforms application. i have a user control with a lot of icons. the user can load this control on a form many times (in a tabbed layout). right now i am loading the icons each time the control is created (could be up to 50 times in teh app). is there any way to cache these icons in the application. if i did this, would that decrease the number of gdi handles that i am using as this is becoming an issue.
You can make a singleton class for each icon. The first reference it creates the handle. Subsequent calls uses the existing handle.
Without knowing more about your user control my next suggestion can be only be very general. But you could have a single bitmap layer on which you draw all your icons. The remaining elements of your user control would exists above and around this bitmap.
Unfortunately this idea may be problematic performance wise. Require you to refactor the code you all ready use for arranging icons. Finally it is non-institutive from how frameworks with a control-form structure ideally works.
We ran into a resource problem with entry forms for the parameteric shape we ship with our CAM software. Too many text entries caused various forms of strangeness and leaks. So we instead created labels with borders that looked like text entries and had ONE text entry (and a combo box entry too). When the user tabs, enters, or clicked the single text entry moved to the new entry and the label was setup for the previous entry.
This is totally a non-intuitive setup than how you would normally code this but it was the only way to deal with our resource problem.
In my experience it seems that GUI Frameworks have issues when you have to deal with dozens or hundreds of entries and that you have to approach the problem using a different design.
If the issue is the number of "icons" (not sure what you mean here) you can use Image-Lists. For example, a Listview control can reference icons in an image-list, instead of keeping a full copy for each item (not sure if this applies to your case though).