I want to make a user control in Windows 10 UWP with changing content.
I know how to make a simple user control, but I need a user control like this:
<Controls:UserControl x:Name="Usercontrol1" Margin="0,10,0,0" Grid.Row="1">
<Controls:UserControl.MainContent>
<Grid x:Name="Content">
//Items are here
</Grid>
</Controls:UserControl.MainContent>
</Controls:UserControl>
I have Grid in my user control that is empty and I want to give this grid different items in every page. I want a way to set a grid for my user control in the page, then add this grid to my user control instead of that empty grid.
Is there any way to do this?
To do this, you need to create a MainContent dependency property in the code-behind of your user control and display it using a ContentPresenter.
Suppose your user control is defined in MyControl.xaml and MyControl.xaml.cs.
Creating the MainContent dependency property
Inside the UserControl class definition in UserControl.xaml.cs add the following:
public static readonly DependencyProperty MainContentProperty =
DependencyProperty.Register(
"MainContent",
typeof( object ),
typeof( MyControl ),
new PropertyMetadata( default( object ) ) );
public object MainContent
{
get { return ( object ) GetValue( MainContentProperty ); }
set { SetValue( MainContentProperty, value ); }
}
As a shortcut in Visual Studio you can write propdp or dependencyProperty (depending on your version) and press the Tab key to automatically fill out a code snippet for the whole property.
Adding ContentPresenter
Inside the MyControl.xaml find the place where you want to display the content and put a ContentPresenter there with a binding to the MainContent property.
There are several ways to do this.
The newest technique with x:Bind syntax
<ContentPresenter Content="{x:Bind MainContent}" />
Using binding with element - here you will need to add a x:Name attribute to the UserControl element itself, call it RootControl for example, and then create the binding like this:
<ContentPresenter Content="{Binding MainContent, ElementName=RootControl}" />
Using binding with DataContext - in the constructor of the UserControl in MyControl.xaml.cs you can set the DataContext - this.DataContext = this; and then write simply:
<ContentPresenter Content="{Binding MainContent}" />
Usage
Now your UserControl is ready and you can use it like this:
<local:MyControl>
<local:MyControl.MainContent>
<!-- some content :-) -->
<Image Source="Assets/LockScreenLogo.png" Width="100"/>
</local:MyControl.MainContent>
</local:MyControl>
Related
In a WPF window, I want to create a placeholder and during the runtime I would like to render or load a UI element in it.
A placeholder in a window looks something like,
<Grid>
<Placeholder1/>
</Grid>
during the runtime, I would like an IconImage to be rendered there.
<Placeholder1>
<Image Source="pack//...." Loaded="Icon_Loaded" /> // Static source
</Placeholder1>
I wish to render the placeholder with the Image during runtime everytime I change Image's property, which should eventually trigger the Icon_Loaded event. I dont want to render the Image(Placeholder) on the startup, but later on.
Background story as to why I wish for a placeholder solution is,
in the below part of XAML part, I wish to trigger the Loaded event handler everytime I change the IconPack's binding property. So as a solution I reckoned, if I render the IconPack element in a placeholder during the runtime everytime I change its binding property, I get to trigger the Loaded event handler for every binding property change.
<IconPack:PackIconFontAwesome Grid.Column="2" Kind="{Binding cbCheckButtonCaptionIconType}"
Foreground="{Binding cbCheckButtonCaptionIconColor}"
Visibility="{Binding cbCheckButtonCaptionIsVisible}"
Loaded="PackIconFontAwesome_Loaded"/>
Could you please show me how to use ContentControl to do the same.
(I tried using TargetUpdated, but it doesnt help in my scenario, so the only option I have is Loaded)
It really depends on what you are trying to do. If your are always using images, use the Image control and bind the source to a property on your view model that contains the path.
private string _imagePath;
public string ImagePath
{
get => _imagePath;
set
{
if (_imagePath == value)
return;
_imagePath = value;
OnPropertyChanged(nameof(ImagePath));
}
}
<Grid>
<Image Source="{Binding ImagePath, TargetNullValue={x:Null}}" />
</Grid>
For more complex content, usually you would use a ContentControl. It has a Content property that you can assign any controls or bind to a property on a view model. It can be used with data templates (if you are not using data templates, you could also use other controls as placeholder, e.g. a Border.).
If you are directly assigning a control to the placeholder in code-behind, it could look like this.
<Grid>
<ContentControl x:Name="Placeholder" />
</Grid>
Placeholder.Content = new Image(...) {...};
If you want to bind a property on a view model and leverage data templating, you could create types:
public class ImageItem
{
public ImageItem(string path)
{
Path = path;
}
public string Path { get; }
}
ImagePath = ...;
Expose a property for the content item in your view model and assign it, e.g.:
public object ContentItem
{
get => _contentItem;
set
{
if (_contentItem == value)
return;
_contentItem = value;
OnPropertyChanged();
}
}
ContentItem = new ImageItem(...);
Then you could create a DataTemplate for this concrete type in XAML.
<DataTemplate DataType="{x:Type local:ImageItem}">
<Image Source="{Binding Path, TargetNullValue={x:Null}}"/>
</DataTemplate>
The resources must be in scope of the ContentControl, then it will automatically select the appropriate data template for the type bound to the Content property.
<Grid>
<ContentControl Content="{Binding ContentItem}" />
</Grid>
As you want to change the content at runtime, please be aware that it is essential to implement INotifyPropertyChanged when binding to properties, otherwise changes to properties will not be reflected in the user interface.
Good afternoon,
I seem to be having a simple issue with WPF.
After googling for few good hours, I couldn't find anything that would resemble what I'm looking for.
To put simply, I'm looking for a way to define an area in my custom UserControl like this:
<UserControl>
<TemplateArea x:Name="FormControls">
</TemplateArea>
</UserControl>
Then do this inside Window, Panel, etc. that uses my custom control:
<TheUserControl>
<TemplateArea x:Name="FormControls">
<TextBox/>
</TemplateArea>
</TheUserControl>
.. and as a result, TextBox will be directly pasted inside of my custom control.
One solution would be to create a dependency property that holds an array of controls, and inside your control you bind it to an ItemsControl:
child.xaml
<UserControl x:Name="RootControl">
<...> <!-- your other UI -->
<ItemsControl ItemSource="{Binding Items, ElementName=RootControl}" />
<!-- style the items and/or panel as you wish -->
</...>
</UserControl>
child.cs
public static readonly DependencyProperty ItemsProperty = DependencyProperty.Register(
"Items", typeof(Observable<UIElement>), typeof(Child),
new PropertyMetadata(new Observable<UIElement>()));
host.xaml
<Page>
<...>
<my:Child>
<my:Child.Items>
<TextBox/>
<CheckBox/>
</my:Child.Items>
</my:Child>
</...>
</Page>
I am developing UWP app and I created new user control and I want to bind it to dependency property in the control's code behind (without the datacontext).
Code Behind:
public Brush Fill
{
get { return (Brush)GetValue(FillProperty); }
set { SetValue(FillProperty, value); }
}
// Using a DependencyProperty as the backing store for Fill. This enables animation, styling, binding, etc...
public static readonly DependencyProperty FillProperty =
DependencyProperty.Register("Fill", typeof(Brush), typeof(MyControl), new PropertyMetadata(new SolidColorBrush(Colors.Black)));
XAML:
...
<Grid>
<Path Fill="{Binding ????}" Stretch="Fill">
...
</Path>
</Grid>
I want that my path's fill property will bind to the property Fill from code behind (the data context should hold different data so I can't use it here)
How can I do that in UWP?
x:Bind would work perfectly on this. Note x:Bind will be looking for properties, methods & events defined in your XAML's code-behind. It's a more performant binding than ElementName.
<Path Fill="{x:Bind Fill, Mode=OneWay}" />
You should be able to use the ElementName property of a binding to circumvent the data context, just as normal WPF allows you to do.
If the property is part of the user control you'll need to assign a name via x:Name to your user control in xaml to access it
<UserControl [...] x:Name="Control"...`
Then use something like{Binding ElementName=Control, Path=Fill}, as long as Fill is a property of your user control.
I'm developing a Windows Phone 8 application with an User Control.
This user control has a border, and I want to create a DependencyProperty to access this border:
public partial class CustomOptionButton : UserControl
{
public Border OuterBorder
{
get
{
return (Border)GetValue(OuterBorderProperty);
}
set
{
SetValue(OuterBorderProperty, value);
}
}
public readonly DependencyProperty OuterBorderProperty =
DependencyProperty.Register("OuterBorder", typeof(Border), typeof(CustomOptionButton), null);
But I don't know how I can bind this property in XAML.
When I have bind a TextBlock.Text, I did this on XAML:
<TextBlock x:Name="CustomText" Text="{Binding ButtonText, ElementName=userControl}" />
But, How can I do the same with the entire Border?
<Border x:Name="OutBorder" BorderBrush="White" BorderThickness="2" Margin="0">
I will need to change the BorderBrush and the BorderThickness (and maybe another properties), so I have thought that I could have only one property instead of three or four.
In this case, you need to create for each type of separate property, because to use one property Border need to create a separate Control like this:
public сlass MyBorderControl : Border
{
// Your implementation of Control
}
If you want to create a property that could be used for any Control, in WPF has attached properties:
MSDN: Attached properties overview
and used like this:
<Canvas>
<Button Canvas.Left="50">Hello</Button>
</Canvas>
In this case, Canvas.Left attached property used for the Button class.
I'm working on a WPF application. I have a Resource Dictionary in which I wrote custom Styles for the ToolTip and for the Button. Actually, for the button i've made two styles.
One of them, has included an image to appear to the left of the content in the buttoon.
<Style x:Key="ButtonImageStyle" TargetType="{x:Type Button}">
........
<TextBlock Margin="5.25,2.417,5.583,5.25" Foreground = White />
<Image x:Name="ButtonImage" Source="/MyProject;component/Images/icoMainMenu01.png" VerticalAlignment="Center" HorizontalAlignment="Center" Margin="-100,0,0,0" Width="16" Height="16"/>
.... </Style
Now, in the MainWindow.xaml i have the following:
<Button Style="{DynamicResource ButtonImageStyle}" x:Name="JustButton" Click="JustButton_Click" Height="50" ToolTip="Press for 1" Content="1" Margin="310,282,400,238" />
I want to be able to change that Image. I will have like 8 buttons and I want each button to have a different image associated with it.
Do you guys have any idea ?
Thanks!
There are various options, from (ab)using properties like the Tag to subclassing or composition in a UserControl, you could also create an attached property.
The cleanest would probably be subclassing though, then you can create a new dependency property for the ImageSource to be used which you then can bind in the default template using a TemplateBinding.
To do the subclassing you can use VS, from the new items choose Custom Control (WPF), this should create a class file and add a base-style to a themes resource dictionary which usually is found in Themes/Generic.xaml. The class would just look like this:
//<Usings>
namespace Test.Controls
{
public class ImageButton : Button
{
public static readonly DependencyProperty ImageProperty =
DependencyProperty.Register("Image", typeof(ImageSource), typeof(ImageButton), new UIPropertyMetadata(null));
public ImageSource Image
{
get { return (ImageSource)GetValue(ImageProperty); }
set { SetValue(ImageProperty, value); }
}
}
}
Now the theme would be more complicated, you can just copy one of the default templates for a button and paste it into the the default style. Then you only need to add your image somewhere but with this binding:
<Image Source="{TemplateBinding Image}" .../>
When you use this control you will then no longer need to reference a style, as everything is in the default style, there is now a property for the image:
<controls:ImageButton Content="Lorem Ipsum"
Image="Img.png"/>
(To use the Tag you would just stick with the normal button and use a TemplateBinding to the tag and set the Tag of the buttons to the URL)
I forgot to mention another possiblity which uses dynamic resources, it's a bit verbose but very simple, see this answer of mine for an example.