I've stuck with one pretty trivial problem (at first look).
Simplified version of my situation looks like this:
I want multiple Background(for example) colors to be applied to SAME Control and to be able to clear only some of them (by condition). WPF does not offer such capability, I can set only one value for each DP.
So, I want to apply Yellow then Green then Red colors successively to Control object and then be able to reset Red so that Control will be with Green background (on the other hand, reseting Green leaves background Red). Looks pretty simple, have you ever created such Decorator for Control? I believe DP internally use such behavior, but there are no public APIs for it.
Please, do not suggest using triggers or any other kinds of conditional DP setting, I really need to set multiple values for single DP and to be able to manage them
Its not a good idea to say "do not suggest" ... Anyway, Well its not possible, and WPF does not do this, what you might meant is the value precendence but this List is fixed, you can't just add another layer in between, for good reasons. The whole system relys on that. Otherwise you could not set one value and use triggers to override it and don't need to take care of resetting the value. Also animations, Style inheritence etc. wouldn't be possible if people start to mess with this list.
So you don't like the trigger idea ... Why? Its exactly for that.
Ok, if you don't like it, how about adding an attached property for Background1, Background2 etc. You also could make Background as an attached property and make it inheritable. You could make an attached behavior, listen to property changes and modify your Background color. You could use a MultiBinding or PriorityBinding.
Well alot of stuff is possible if the obvious solution is not desired :)
Related
I have a Button in Silverlight. I need to change its style at runtime. The style of this Button needs to change multiple times during the life of the application. Is this possible in Silverlight? If not, what is a good workaround?
Thank you!
Consider using the VisualStateManager to change the state of the button as appropriate.
You could create your own states for each of the different styles you wish to show.
Yes, it's possible, but I'd think hard about what exactly you're trying to do by changing the style itself because there's probably an easier way. You've probably already run into the fact that you can't simply assign a new style to the button with something like MyButton.Style = (Style)FindName("NewButtonStyle"). So you do need some kind of alternative.
The VisualStateManager is the first and easiest way of handling most kinds of changes that you would normally want to do to a control. You can pretty easily set changes to occur on the normal sorts of visible states (hover, focus, mousedown, mouseup) and it'll animate those state changes correctly from whatever state you're in to whatever other state you need.
If the kind of change you're looking for is more extensive, changing the type of control to, say, a ContentControl and then catching the mousedown/mouseup events from there might be a better workaround. This is obviously a bigger deal (and you lose the simplicity of having a button), but you'd be able to get whatever changes you wanted to pretty easily by just swapping out the Content property.
Somewhere between the two (and something I'll mention because it's possible, not because I recommend it) would be to actually manipulate the Style definition itself. The Button will pick up the changes and adjust itself. I'm going to repeat myself here though: I don't recommend this and I can't envision a scenario where I'd prefer doing this over using the VSM or using something other than a Button entirely. But it is possible to get into Application.Current.Resources["Style"] as Style and muck about with whatever you please. The bigger question then is why and whether what you're doing can be done some other way that would make more sense for whoever's going to maintain your code later. Personally, I expect Styles to be pretty static and I think that's the general consensus too.
Sure you can....
if you have a style stored locally you can access it like that :
rec1.Style = (Style)this.Resources["style1"];
I have a following requirement for a very complex UI. (Complex here means there are lot of controls in the form [approximately 100]). I am using MVVM (if my problem requires it to slightly go away from MVVM I am ok with it)
My question is for Editable ComboBox and TextBox. But I would say I like to hear a common algorithm which will fit all controls.
Requirement 1 : The user edits the content and goes to next control, the color of the control/text should become red.
Requirement 2 : When the user comes back to the previously edited control and enters the value which was initially present, the color of the control/text should become back to black.
I know the requirement is tough and I have been breaking my head to design a generic algorithm using which I can store the previous value and call a function to change the color of control.
To just give you all an idea, --> I tried storing 2 properties for every TextBox like Default_Text and Text. But since the number of properties are huge, the memory footprint is very huge. Also maintaining so many properties is very tough.
--> I tried adding a Dictionary to every ViewModel to store what values have got changed. But here the problem I faced was giving unique keys to all the controls in my application, which is not very helpful
--> I had even thought and tried about subclassing controls like TextBox, ComboBox and overriding some methods to suit my requirement, but sadly I failed miserabley when I started adding validations and all.
So here I am stuck with designing a generic WPF property system/algorithm to handle all undo redo functionality, changing styles of controls,etc!!!
It will be really great if you experts can guide me in right direction and also help me in developing such an algorithm/system. A sample illustration will be nice though!!!
I found an answer to the above problem. I used attached behavior for this. More details on this link Function call from XAML from StackOverFlow.
When I databind, I store the initial value of the DataBound variable in the Tag property by using Binding=OneWay. Then I have written a attached behaviour for LostFocus event. Whenever the user enters a control and then goes to other control, it fires LostFocus event and calls my attached behaviour. In this, I check whether the value is equal to the value in Tag. If it is same, I display in black else I display in red.
Attached Behaviour rocks in WPF. I can achieve anything from that cleanly without code cluttering!!!!
Another alternative is to use some "dirty" tracking in your models (or viewmodels) and bind to a properties isdirty (and convert it to a color).
As you know, the built-in themes all define styles for the standard controls such as the TreeView control. We're trying to create something that looks an awful lot like a TreeView but isn't actually one, nor is it a subclass of one. It just has parts that we want to look like one for consistency.
For instance, our control too has a selected item whose background we'd love to match to the appearance of the background for the selected item in a TreeView (or more accurately the TreeViewItem) for the current theme. (You can't simply use highlight color as the themes have nice gradient brushes and borders, not just a solid brush.) Same with our expand/collapse togglebuttons. We want them to look just like the ones used in a TreeView for the current theme. (i.e. Sometimes a triangle, sometimes a box with a '+' in it, etc.)
Now while we can simply rip open Expression and copy the styles ourselves (or at least the parts that we need), we'd have to do that for each and every theme that MS provides. Plus, that wouldn't handle newer themes. And in a purest standpoint, that's duplicate styling information which just sits wrong with me.
Also, if someone styles the actual TreeView(Item), we want to pick it up as well. Since the parts that we want to style are required parts of a TreeView, we feel pretty confident that they're in there somewhere style-wise.
Not even sure what I want to do is possible but if anyone knows, they're most likely here on SO!
Yet another question close to a month old without even a comment. Very odd for the SO community to not chime in at least once! Guess it's not possible.
Well, what we ended up doing was using 'Show Me The Template' (Google it) to get the templates for the part (we don't have Expression), then manually managing them ourselves instead of using the built-in styles. NOT at all what we wanted to do since we don't know of a way to get the nice gradients that are defined in the system already without duplicating them, but the end result does match perfectly so there's that. As such, this too is getting marked as the answer. I'll gladly change it if someone else actually gives me one that works (or is close enough! Just need something people! Feel like I'm posting in a vacuum here!
I'm pretty green when it comes to WPF, so forgive me if this is an obvious question.
I'm trying to modify an existing code base that is using the Divelements SandRibbon libraries, but am finding that the GalleryButton control doesn't behave quite how I'd like. What I'd like to do is change the way GalleryButton arranges the image and label, but keep the default 'look' for all triggers such as mouse over etc.
Is it possible to apply a ControlTemplate to some parts of a control but not others? I want to specify that the GalleryButton displays its 'Image' and 'Text' properties differently than the defaults, but not touch anything else.
Unfortunately no -- it's all or nothing. However, one solution I've used before is to simply sublass the control and alter the layout in code behind in OnApplyTemplate.
I asked a similar question about this previously, but I did not specify that this needs to work in Partial-Trust mode. Unfortunately both correct answers (using UIElement.BitmapEffect or UIElement.Effect) are not allowed in Partial-Trust, because it requires UIPermissionWindow.AllWindows.
Does anyone know of a way to do something similar to the OuterGlowBitmapEffect in a Partial-Trust app?
If you need a rectangle outline, you can attach an Adorner with a simple rectangle in it. It's not going to have the glow effect you are looking for, though.
If you need a non-rectangle outline, you can still use Adorner, but you also need to specify opacity mask, based on a visualBrush on your object. You will also have to make the adorner a little bit bigger than the source visual, to make it look like it surrounds the object instead of overlapping it.
If you want to go fancy, you can encapsulate attaching the adorner in an attached dependency property and just attach it to any visual you need to outline.
If you don't want to bother with adorners, you could have two separate templates for you visual - one with the outline pre-created and one without and switch them as needed. However, this requires you to know upfront what cvisuals you would need to outline and what is their style. Granted, you can make it quite flexible with data binding, but still it's not a generic solution to your problem.