I try to use inheriting in WPF. I have asked a question about this earlier, but no one answered correct. So I try to make a BaseWindow class with some UI elements and I want that other windows, that inherit my BaseWindow would have these UI elements. How to do that. My practise with WinForms applications dont work anymore. Maybe there are some simple examples or smth..? Thanks
If you want to inherit from a window, you need to create an implementation of a window in code only, and you can then inherit from this - note that your Window declaration in the XAML would need to change to point to this code, e.g.
<src:BaseWindow xmlns:src="clr-namespace:BaseWindowNamespace" ...>
If you define the base window using XAML, you'll get the following errors:
"'WpfApplication1.Window1.InitializeComponent()'
hides inherited member
BaseWindowNamespace.BaseWindow.InitializeComponent()'.
Use the new keyword if hiding was
intended"
"BaseWindowNamespace.BaseWindow cannot
be the root of a XAML file because it
was defined using XAML"
Now, at this point, I must point out that this is counter to the way that you should handle composition of your window. The "standard" way of doing this would be to use content templates to display user controls which could be swapped and styled to achieve different looks and functionality. In this way, the function of the window becomes that of a harness, and you can achieve a clean separation of content which can be easily implemented using MVVM.
Did you try the BasedOn tag? I don't know about windows, but that's what you use for UserControls AFAIK.
Related
I have built a User Control composed, as usual, of a XAML part and a code-behind part. Now, I need to create another User Control which shares some of the functionalities of the former, but which has different looks and might also have additional features in the code-behind.
My first idea was to create an interface to gather the common functionalities of the two types of controls. Is this the right way to go? And how would I manage the different XAML parts I should have? Any advice is welcome.
I would like to add another contribution which I think might be useful to others encountering my same situation.
One other possible solution, which in my opinion is suitable if the controls you are going to create are not particularly complex, is to create a base User Control containing the common features that you want to share: such control will be written entirely in C#.
This, in fact, allows inheritance in User Controls composed of both XAML and code behind. In the XAML of the inherited control, rather than having
<UserControl> ... </UserControl>
You will have
<MyProject: MyBaseControl x:Class="MyProject.MyExtendedControl"> ... </MyProject: MyBaseControl>
and then in the code behind you will also need to specify the following:
class MyExtendedControl : MyBaseControl
Hope this helps.
User controls don't lend themselves well to inheritance in WPF, you can do some hacks to make it work, but overall you'll probably be better off using a Custom Control instead. It's easier to specify different XAML for inherited controls using this technique. The easiest way to get started with a custom control is to add a new item to your project of type "Custom Control (WPF)" and it will add the control and the XAML gets added to Themes/generic.xaml for you.
To inherit from this control, the easiest way is to add another new Custom Control (WPF) and then change the code behind to inherit from your parent control instead of Control.
There are a number of ways to split up the pieces to make them easier to work with.
MVVM, as mentioned in a comment, relies upon Data Binding to separate the input controls from logic. By setting the appropriate class which implements INotifyPropertyChanged into the DataContext of you control, you can change the behaviour. Your DataContext class or ViewModel could implement Visibility properties to show and hide different parts of the input if the differences are not too great between the uses.
Another way to break apart functionality is by Aggregation. See StackOverflow 269496
You could build smaller controls that implement common functionality and then build larger special purpose controls by combining the smaller controls (i.e. aggregating them) to make the larger control. Aggregation will work for both the code-behind and the Data Binding approaches.
I'm having a couple of major issues when trying to style the ChildWindow control from the SDK.
First issue:
ChildWindow doesn't pick up implicit styles. I understand why, it's because the actual child window is always a derived class.
I know that I can just use an explicit style instead and that's my current solution, but is there any other way to work around this problem so that I don't have to remember to explicitly tag all child windows with the same common style?
Second issue:
We're using Prism 4 and I have a child window instance in a module that is loaded dynamically by the Prism infrastructure. It picks up the explicit child window style, but it doesn't pick up any other implicit styles defined in the shell's App.xaml (such as the TextBox control template).
This only appears to be a problem inside dynamic modules, it's fine with shell-based windows. Any ideas why this is happening and what I can do to fix it?
For your first issue, are you targeting ChildWindow to style a derived one? If so, you need to specified the derived type for the TargetType so that the implcicit style can kick in.
As for your second issue, I am not 100% sure how to fix this but what we found out is that if you declare your implicit styles inside the main window's resources, it will be applied to the controls that reside in your external modules. But I think that this was not working for explicit styles though...
Turns out that Prism wasn't the problem - there were implicit styles defined in the child windows that were wiping out the implicit styles from the shell because they weren't using BasedOn. After adding this attribute everything works fine now.
I am new to Silverlight, but I couldn't find anything about this when I googled it.
I have a button that I am trying to set the style programatically. I have the style defined in a XAML file and I want to pull the style into C# so I can dynamically create a button and assign it this style. So far, this is what I am trying:
button.Style = (Style)Resources["CloseButtonStyle"];
However, it just makes the button have no style. Is there an easy way to do this? I feel like this should be obvious, but I can't get it to work.
You are assuming that your Resources property on the current object is the one that contains the defined style. However, I assume, given the symptoms of your issue, that CloseButtonStyle is actually defined further up the control hierarchy.
Instead, you need to traverse your control hierarchy until you find the resource (or if you know the object that defines it, just refer directly to that object). Unfortunately, Silverlight doesn't include FindResource call like WPF, but it's not too difficult to implement your own.
I can call button1.Style = (Style)Resources["NonExistentKey"]; and it makes my button have no style at all as well, point being that the resource is probably not being found, you won't get an exception.
You directly access the Resources property, but is the style really in the immediate resource dictionary of your Window/UserControl/whatever-you-have?
I wanted to know which one amongst Style and UserControl would be better to use in WPF?
For example:
I have created an image button in two different ways.
One uses Style and ContentTemplate property is set.
It uses one other class with dependency properties.
The other way is I have created a UserControl which has a button and its content property is set.
The file UserControl.xaml.cs also contains the dependency properties.
For Code details see the answers of this question:
Custom button template in WPF
Which one would be better to use? In which scenario should one go for Style or UserControl or any CustomControl?
Styles are limited to setting default properties on XAML elements. For example, when I set the BorderBrush , I can specify the brush but not the width of the border. For complete freedom of a control’s appearance, use templates. To do this, create a style and specify the Template property.
Styles and templates still only allow you to change the appearance of a control. To add behavior and other features, you’ll need to create a custom control.
For example,
To create a button like a play button use styles and templates, but to create a a play button which will change its appearance after pausing it use UserControl.
For this type of thing I would go with Style, even though I'm not really adept with graphical tools. I tend to produce a basic, boring style that I can get started with and then prettify it once the application functionality has been verified.
The nicest thing about WPF is being able to distance much of the graphical look, feel and behaviour away from the code.
This allows you to change the style of your application without revisiting the code and indeed means that you can change styles on the fly at runtime.
There is an awkward line to tread with regards to how much behaviour is placed within the XAML and how much is placed within the code. A rough guide would be to decide on what behaviour must always be present within the UI and place that in the code, everything else place within the XAML.
Think of the code as being an abstract class with defined interfaces and the XAML Styles as being classes based on that class and you'll get an idea of what I mean.
Conversely, I know that people who are far more adept at the GUI work prefer to put more functionality in the XAML and others who prefer the code side, because they find the GUI work slow or difficult.
When thought of that way you'll see that there's never really a right or wrong answer, just better solutions that suit your skills.
I'm just getting my feet wet in Silverlight, and don't really understand the differences and pros/cons of creating a UserControl vs. creating a Control for the same task (as in when you right click on a selection in Expression Blend, for instance).
It seems like selecting "Make Into Control" just creates a new template for the base type you specify, whereas creating a UserControl creates a whole new base class. Is that correct?
In this particular instance, I'm creating a custom text box control that only takes numbers, and divides itself into 3 sections, storing 3 values into separate properties as pictured below. In this particular case, which would be best?
UserControls are meant to be a composite control - basically a bunch of other "controls" grouped together to work as a single, cohesive unit.
Custom Controls, on the other hand, are intended to be used as a single control. Think of the basic controls in the framework, such as TextBox or Button - if you were implementing something like that, you'd want a Control. (This is less common than UserControls, especially in WPF, since you can use templating on base class controls to accomplish quite a few things where you'd need custom controls in other frameworks). A custom Control is all about defining new behavior for a single "control."
If you consider your control to be a group of three text boxes then a UserControl would be appropriate, but if your control will still essentially be a TextBox then you should extend the existing control with "Make into control."
It sounds like you need a UserControl to me.
Dov, I think you've answered your own question with your update. Custom Controls are most useful when you want to make a control that supports templating. Otherwise they are useful when you are inheriting from other controls to cleanly add functionality (TextBox -> PasswordTextBox).