I want to create a template (resource dictionary) for my app. where my type inherits the button type and I then can call it through:
<my-custom-type inherit from button>
</my-custom-type inherit from button>
And of course in WPF.
More specifically, I would like to create copies of the control in the image below with simple XAML syntax as above.
There are two approaches to this, each with their own pros and cons:
Templates allow you to reuse a section of XAML. There is (almost always) no code-behind, and you certainly won't be deriving from Button. For example, if you wanted to have a bordered text box repeated in an ItemsControl:
<DataTemplate x:Key="MyDataTemplate">
<Border>
<TextBox/>
</Border>
</DataTemplate>
Or in a button class you use ContentTemplate:
<Button ContentTemplate={StaticResource MyTemplate}>
</Button>
And you would use it as XTemplate="{StaticResource MyDataTemplate}" in an existing control that used templates. This is usually the way to go. Note that the name of the property won't be Template, but ItemTemplate, or ContentTemplate or something similar.
The exception is if you want custom behavior, in which case you use a UserControl. This technically could inherit from Button though you usually wouldn't. Subclassing a basic control should only be done if you are sure you actually want to do that. Once your user control is created, the syntax would look similar to what you have in your question:
<local:MyButton>
</local:MyButton>
Note that "local" is a made-up xmlns. Your user control would consist of whatever controls you wanted, and you can expose "attributes" to the using code via dependency properties.
Related
I need to use a different panel for a particular section/group in my ListView. How do I do that (using XAML, C#, or anything)? I already tried using GroupedStyleSelector but it didn't work (I researched about it but it turned out it's not designed for this purpose). Here's my XAML right now:
<ListView ItemsSource="{Binding Source={StaticResource cvs}}">
<ListView.GroupStyle>
<GroupStyle HidesIfEmpty="True">
<GroupStyle.Panel>
<ItemsPanelTemplate>
// I want to change this for a particular group
<uwp:SGStaggeredPanel/>
</ItemsPanelTemplate>
</GroupStyle.Panel>
</GroupStyle>
</ListView.GroupStyle>
</ListView>
I'm thinking of subclassing the panel, but the problem is how do I get a reference to the current group?
https://learn.microsoft.com/en-us/windows/communitytoolkit/extensions/listviewbase
The above article talks about a WCT goody that allows you to dynamically change the Tamplate of the item that is about to be rendered, this particular example is a statically expressed extension that simply works as an attached property to a listview and cycles through two different templates
But you can easily extend ListView into a templated control and then more easily have access to the Viewmodel that houses your Itemsource, from then you can go on to change the
private static void ItemTemplateContainerContentChanging(Windows.UI.Xaml.Controls.ListViewBase sender, ContainerContentChangingEventArgs args)
which is where all the magic takes place.
Notation for implementation
Note 0:
if you don't know mvvm and binding, forget you ever read this and go study it up instead.
Note 1:
All child controls that have no explicitly defined Data Context will inherit their parents.
Note 2:
You will be able to Map incoming controls in the aforementioned function by tracking the incoming args.ItemIndex and then cross checking it with the binded source (Observable list etc) that is housed on the underlying datacontext.
Note 3:
To convert this into a tamplated/custom control you will have to pretty much make your own implementation of ListView like this MyListview:ListView
The Dependency properties will have to be converted to conventional ones,
just type 'propdp' and double tap Tab, to bring up the default tamplate.
You will still have to reference all the different DataTamplates from XAML like its shown in the showcase app listed bellow.
Note 4:
Cut the slack off that showcase code, the stretch direction and the zebra stripes for example are not needed in your case.
https://github.com/windows-toolkit/WindowsCommunityToolkit/blob/master/Microsoft.Toolkit.Uwp.UI/Extensions/ListViewBase/ListViewExtensions.cs
this is the exact location of the code piece i talked about, to check it out in action and play with it, Download 'Windows Community Toolkit' from the store, it is in the Extensions section.
I am new to WPF and C#. I need to create a Label and a Button which is in a Template.xaml. But the number of Label and Button creation is user specific which is another design.xaml. i.e if the user gives value 5, then five Label and Button needs to be created using the Template.xaml file.
I tried with something like below in design.xaml,
xmlns:local="clr-namespace:UserDesign"
<local:Template HorizontalAlignment="Left" VerticalAlignment="Top" />
<local:Template HorizontalAlignment="Left" VerticalAlignment="Top" />
<local:Template HorizontalAlignment="Left" VerticalAlignment="Top" />
But this seems to be a fixed one. I need to do this dynamically based on user input.
Without a more complete code example, it's hard to know exactly what your scenario is. But if what you're dealing with is a collection of objects, where each object corresponds to a single instance of some Template object (which presumably contains your Label and Button object), then you probably want to use WPF's data-templating features.
There is a reasonably good tutorial here: Data Templating Overview
The basic idea is to declare a DataTemplate object which is used for the ItemTemplate property of ItemsControl or a sub-class (e.g. ListBox). The DataTemplate will be declared to apply to a specific data type (e.g. the object type in your collection), and you will use bindings between the UI elements in the template and the data type to customize those elements for each data object.
Depending on what your Template itself is declared as, that might wind up being appropriate for use in a DataTemplate declaration. Or it might not…it's impossible to say without seeing an actual good, minimal, complete code example.
I have a class library, in which I've created default styles for TextBlock, which is applied to every TextBlock in any application that uses this class library.
The problem is that I sometimes need to exclude TextBlocks inside some other controls (say, ribbon, or my own Custom Control). The textblocks are not accessible, for instance the ones inside a tab item heade.
Is there any ways to force wpf to use another style for all TextBlocks inside one control?
Thanks
Simply add an empty (or any other) style to the resource dictionary of any ancestor of the TextBlock nested inside the control referencing the resource dictionary, in which the global style is defined. For instance, the global style defined for TextBlock won't be applied in this case (if the resource dictionary is referenced by an ancestor of the Button control):
<Button>
<Button.Resources>
<Style TargetType="TextBlock"/>
</Button.Resources>
<TextBlock Text="FooBar"/>
<Button>
Ok. As it turns out, this is not possible, see Mike Strobel's answer for an explanation of the reason and the rational behind it.
The workaround is to not create an implicit style for TextBlock, because it will affect TextBlocks inside other ControlTemplates.
What works for me is to derive a class from TextBlock, say Label and apply my style to it, and then use it wherever I want a TextBlock with that specific style.
A more "Wpf Natural" way to deal with that is to create a style with a key.
seems like a trivial task: i am building a wpf application, using MVVM pattern. what i want is dynamically change part of a view, using different UserControls, dependent on user input.
let's say, i have got 2 UserControls, one with a button, and another with a label.
in main view i have a container for that. following XAML "works":
<GroupBox Header="container" >
<local:UserControlButton />
</GroupBox>
and a UserControl element with buttons pops up. if i change it to another one, it works too.
question is how to feed that groupbox dynamically. if i put something like that in my model view:
private UserControl _myControl;
public UserControl MyControl
{
get
{
return _myControl;
}
set
{
_myControl= value;
InvokePropertyChanged("MyControl");
}
}
and change my view XAML to something like:
<GroupBox Header="container" >
<ItemsControl ItemsSource="{Binding MyControl}" />
</GroupBox>
and feed it from command with usercontrol for button or for label: nothing happens, although "MyControl" variable is set and is "invoke property changed"..
Obviously there are many ways to skin this particular cat - but to answer the question of why it doesn't work you need to look into the ItemsSource property of ItemsControl on MSDN.
The items control is designed to show multiple items, provided through an IEnumerable passed to the ItemsSource property. You are passing a UserControl, so the binding will fail.
For your example, I would change the ItemsControl to a ContentControl and bind the content to your MyControl property. This should then work.
<GroupBox Header="container" >
<ContentControl Content="{Binding MyControl}" />
</GroupBox>
However, I would strongly recommend looking into other ways of doing this - having a control in your VM breaks MVVM to my mind. Depending on what you are doing look at data templates - #Sheridan's link in the comments provides an great description of a way to do it.
Couldn't post this as a comment so adding as answer..
Have a look at this:
Implementing an own "Factory" for reusing Views in WPF
It uses DataTemplates but doesn't require the DataTemplate section for each view. If you potentially have a lot of user controls/views you wish to display or you are reusing through multiple views or you are intending to actually dynamically generate a view (versus just loading an existing user control) then this might suite your needs.
Given:
<StackPanel>
<View:ArcController x:Name="control1" Visibility="{Binding Path=CanShowDateControl, Converter={StaticResource bool2VisibilityConverter}}" />
<my1:DateLabelView x:Name="control2" DataContext="{Binding Path=DateLabelViewModel}" Visibility="{Binding ElementName=ctrlTableToolbar, Path=DataContext.IsDateReadOnly, Converter={StaticResource bool2VisibilityConverter}}" />
</StackPanel>
I have two controls (control1, and control2) inside a stackpanel, and at one time i want to show only one of the controls.
As shown in the code, the visibility of the controls is driven by "IsDateReadOnly" and "CanShowDateControl".
And, as per my viewmodel logic... CanShowDateControl = !IsReadOnly.
So, at one time I will ONLY show one of the two controls.
Question: My problem is, though i am showing only one control at a time, my xaml is creating instance of both the controls. Is it possible to create instance of only the control that i am showing?
Give that:
1) I want to show/hide using binding, so that logic lies in my viewmodel.
2) I can keep these two controls inside one wrapper control. Since i am using it at different places.
Thanks for your interest.
Use a ContentControl and ContentTemplateSelector with two DataTemplates. One for ReadOnly and other for Not ReadOnly.
In the selector, based on the property, return appropriate DataTemplate.
Other way you could go is create a Custom Control which has two (or more if more than two) properties to store two controls. Based on a condition, it should add one of them to the Visual Tree which will prevent the other one from being loaded.