I am creating a custom control derived from the one of the Standard WPF controls. The control has several constituent parts,and I am only modifying one of those parts.
Here's my question: If I am modifying only one part of a control, do I have to declare the control as lookless and reproduce the entire control template for the modified control in Generic.xaml, or can I omit the lookless declaration (found in the static constructor provided by Visual Studio) and simply modify the control template for the part I am extending?
I have tried the latter approach, and my control template is being ignored. I would like to get confirmation before I reproduce the entire control template, since what I am extending is the WPF Calendar. Thanks for your help.
It sounds like your best bet is to paste the entire template and modify the parts you need, although you didn't say exactly what you want to do or post any code.
Obviously if what you want to change about the calendar has a property you can modify in xaml, then that is easier. The opposite extreme would be to create a custom control (subclass).
I wanted to change the color or the ComboBox arrow the other day and the easiest way to do that was to past the entire template into a style and apply as needed, after changing one single part of the template (the arrow color, of course). There is no exposed DP to change for this and I didn't need anything more complicated than that.
HTH,
Berryl
The declaration that's generated for you by default is simply allowing for a default implicit Style to be defined for your control instead of just taking on the default Style of the base type.
DefaultStyleKeyProperty.OverrideMetadata(typeof(MyControl), new FrameworkPropertyMetadata(typeof(MyControl)));
What makes a control lookless isn't any specific declaration but rather it's definition in a code file which will then have some ControlTemplate applied to it at runtime. The alternative is the UserControl style of declaring a XAML+code-behind class which compiles into a single class with both UI and logic.
A simple example: Button is not the thing you see on the screen and click on; Button is a control that can take a single piece of Content and translate a user click into a Click event or Command call. What you see on the screen is just a visual template on top of Button's inherent behavior and state.
Related
So much reading, and so much about inheritance, I can't find any direct answers, so here goes.
If you have a base-class derived to do certain things, look or act a certain way, you can subclass it and get all the functionality of the parent class with only slightly modified differential. The same does not appear to be the same for working with WPF Themes... more specifically, the combobox control (similar issues with textbox, but that's obviously less complex).
By looking at the Control Template Examples, they discuss the entire structure of it, the borders, backgrounds, glyphs, actions, properties, etc.
If the ONLY thing I want to do with a combobox is to change the border of it to Red if there is an error in it, it appears, I have to basically redefine the entire thing and somehow put in my custom trigger setting / color to be implemented.
Somewhat similar is that of the textbox control and how its created. It has the named control when trying to nuts around with the background color... you can't just say... background = some static brush value.
What shortcuts are out there to only allow overriding these small elements without having to re-create the entire template control. I can just imagine what would go on with grids, tabbed controls, and others that could get extremely messed up if you miss one simple thing.
I also see that some controls are made up of OTHER Control.Templates, so how might I be able to attach to changing the property setting on just the single element of the control template... Such as the combobox has the control template for the Toggle Button. From that, it has a border via x:Name="Border" and I want to change THAT element within a derived style.
Thanks
I might not understand your question here. But from what i get is:
Yes you can't partially implement Templates, in fact i wouldn't know how this could be possible. But, if you want to change certain things, you can of course do that. You can create Styles, Templates, Brushes etc. as DependencyProperties and use TemplateBinding to bind to them, on the given child control.
Remember that WPF allows always to change the template on the fly. if we could partially change the template this would might hurt performance or could get messy and complicated. Still, you can do that using ContentControls and TemplateBinding or simply Triggers.
For my custom controls, which might contain multiple part sub controls, i usually add a style for them. For example, a custom ComboBox would contain a ToggleButtonStyle.
One thing that would be nice though, would be to add control template triggers without the need to reimplement the template.
Is there a way to globally change the validation template? I need to make a couple of minor tweaks to it and I don't want to have to edit every single template.
To my knowledge, no there isn't. If you're talking about the red border and the sliding popup around TextBoxes, ComboBoxes, etc. They are coded into each control's own ControlTemplate and not referenced (like a Behavior) from a common source. You'd have to redefine the implicit styles for all used basic control, or write your own validation behavior which is independent of the control (e.g. put a red border around it and write some text too) and attach it to every control you use.
I just want to wrap a standard control with some more additional properties (look stay the same, I don't want to do theming in first stage).
Can I just inherit from this standard control instead of UserControl or Control ? In fact I read it is obligatoryb to use Custom Control Project Template and not UserControl ontrol Project Template. Why ?
Update: I try with a Custom Control Project and inherit from the standard slider but I have nothing show up visually ! Now what should I do to have the same visual slider as the standard one ?
I know the difference between a user control and a custom control but in practice how do you do when you just want ONE single standard control ? How will a slider for example resize AUTOMATICALLY if I encapsulate it inside a User Control instead of a Custom Control ?
A custom control is a single control and can derive from another control, this would support styling. A UserControl is a composite control out of many different controls, and as a whole, doesn't support styling (the parts do however).
If you want to add features of any kind to an existing control, derive from it. If you want to pack several controls together to make it easier to handle them (you could still add DP's to it), use a UserControl.
A custom control alone won't do anything related to resizing etc, that is dependent on the settings you supply to it from the outside (ie. HorizontalAlignment, VerticalAlignment and others) when you used it in a container. The custom control should inherit the default template from the base class unless you override it.
I have a datagrid, and certain columns need to contain text that is linked to a detail window. So, in order to make it a bit easier on myself, I created a UserControl that is basically a Button with a control template that contains a TextBlock (I could have done this a number of other ways, I know, but I figured the button already exposes a Click event, so why not?). Things are getting a bit hairy, though, when it comes to styling: I'd like to give the text a "hyperlink" sort of format--blue text, underlined--so that it's clear they are links (also, so that they resemble to format in the legacy WinForms application I'm re-implementing). But I would also like to be able to style the text--ideally, it should grab things like text color if text color is set in a style on the parent cell.
Basically, is there an easy way to implement a custom UserControl that will a) grab styles from a parent element and b) apply its default styles in a low-priority way, i.e. only apply a specific style if there's not already one set from the parent? I know I can pass the parent's style manually through a binding, but I was wondering if there was an easier way.
It sounds like you need to create a true Control or ContentControl implementation for this, so that you can override the true styles and templates.
UserControls are not really stylable, unless you start somehow creating custom properties for binding Styles.. but none of that will be implicit.
I'm trying to create a control in Silverlight that inherits from Button so that I can perform a specific action everytime it is clicked. I'm doing this because I'd like to reuse this custom button in several locations with the same functionality.
I'd like to create the control in such a way so that I have a can set the custom Button's Content to a specific default icon image, but still have the rest of the button's style coming from either the default button style, or being automatically set by the toolkit Themes.
I'd also like to have the Content be described and editable in XAML rather than code if possible.
It seems like this would be a pretty common problem for Silverlight developers - is there a good way to tackle it?
If you use a normal button and edit an "Empty Template", then you can style the button to have any content you wish and expose properties that you can set in the XAML for Icons etc.
By using the standard button control, you will have all the behaviors that you require.
I believe this is what you're looking for, if not can you expand on your question.
--EDIT--
Ok, I get what you are trying to do now. So what you might want to consider is creating a custom button class that inherits from Button. Then you can override the OnClick method to handle your logic. When it comes to the XAML, you can create a template style for a TargetType of your custom button class, that would be styled to your requirements.
HTH, if you need some examples place a comment and I'll mock up some examples