Develop Reference

C# WPF Prism RegionManager failed to navigate

Using WPF .Net Core 3.1 + Prism.
I've implemented TabControl with dynamically added TabItems.
RegionManager works just fine when trying to navigate to region within MainWindow, but it failed when trying to navigate to region whithin the TabPage. Does not work neither from MainWindowViewModel, nor from TabPageViewModel.
Project's repo may be found here: GitHub.
MainWindow.xaml:
<TabControl Margin="10" ItemsSource="{Binding TabPages, UpdateSourceTrigger=PropertyChanged}">
<TabControl.Resources>
<DataTemplate DataType="{x:Type viewmodels:SomeTabPageViewModel}">
<views:SomeTabPage/>
</DataTemplate>
</TabControl.Resources>
<TabControl.ItemTemplate>
<DataTemplate DataType="{x:Type interfaces:ITabPage}" x:Name="dt">
<Grid VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Height="40">
<TextBlock Grid.Column="1" Margin="5,10,10,10" Text="{Binding TabName}" TextAlignment="Center" VerticalAlignment="Center" FontSize="16"/>
</Grid>
</DataTemplate>
</TabControl.ItemTemplate>
</TabControl>
SomeTabPage.xaml:
<UserControl x:Class="WpfPrismRegionFailure.Views.SomeTabPage"
xmlns:prism="http://prismlibrary.com/"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="50"/>
<RowDefinition Height="Auto"/>
<RowDefinition/>
</Grid.RowDefinitions>
<Button Grid.Row="0" Content="Navigate From Inside Of TabPage (not working)" Command="{Binding NavigateFromInsideOfTabPageCommand}" FontSize="16" Background="Orange"/>
<TextBlock Grid.Row="1" Margin="10,20,0,0" Text="The area below contains region 'RegionInsideTabPage', but can't navigate to it." FontSize="16"/>
<Border Grid.Row="2" BorderBrush="Orange" BorderThickness="2" CornerRadius="10" Margin="10">
<ContentControl Margin="10" prism:RegionManager.RegionName="RegionInsideTabPage"/>
</Border>
</Grid>
</UserControl>
SomeTabPageViewModel.cs:
using Prism.Commands;
using Prism.Ioc;
using Prism.Regions;
using System.Windows.Input;
using WpfPrismRegionFailure.Base;
namespace WpfPrismRegionFailure.ViewModels
{
public class SomeTabPageViewModel : TabPageBase
{
public SomeTabPageViewModel(IContainerProvider containerProvider) : base(containerProvider)
{
this.NavigateFromInsideOfTabPageCommand = new DelegateCommand(OnNavigateFromInsideOfTabPage);
}
public SomeTabPageViewModel(IRegionManager regionManager) : base (regionManager)
{
this.NavigateFromInsideOfTabPageCommand = new DelegateCommand(OnNavigateFromInsideOfTabPage);
}
public ICommand NavigateFromInsideOfTabPageCommand { get; }
private void OnNavigateFromInsideOfTabPage()
{
System.Diagnostics.Trace.WriteLine($"SomeTabPageViewModel _regionManager ContainsRegionWithName RegionInsideTabPage: {this._regionManager.Regions.ContainsRegionWithName("RegionInsideTabPage")}");
this._regionManager.RequestNavigate("RegionInsideTabPage", "RegionContent");
}
}
}
Inside of TabPageViewModel regionManager.Regions.ContainsRegionWithName("RegionInsideTabPage") returns 'false' despite of the region is being declared in XAML
<ContentControl Margin="10" prism:RegionManager.RegionName="RegionInsideTabPage"/>
Project's repo may be found here: GitHub.
Someone heeeeeeelp me please

WPF Custom Control Not Displaying Data

Here I have my custom control:
xaml:
<UserControl x:Class="Tasks.Assets.Objects.Card"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:Tasks.Assets.Objects"
mc:Ignorable="d"
d:DesignHeight="200" d:DesignWidth="150">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="10"/>
<ColumnDefinition Width="1*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="135"/>
<RowDefinition Height="5"/>
<RowDefinition Height="30"/>
<RowDefinition Height="30"/>
</Grid.RowDefinitions>
<Rectangle Fill="{DynamicResource MutedWhite}" Grid.RowSpan="4" Grid.ColumnSpan="2"/>
<TextBlock x:Name="textBlock" Grid.Column="1" Text="{Binding Path=Title}" TextWrapping="Wrap" FontFamily="/Tasks;component/Assets/Fonts/#Abel" FontSize="24"/>
<Rectangle Fill="{DynamicResource MutedGrey}" Grid.Row="1" Grid.ColumnSpan="2"/>
</Grid>
C# Code Behind:
public partial class Card : UserControl
{
public Card()
{
InitializeComponent();
}
public string Title
{
get { return (string)GetValue(TitleProperty); }
set { SetValue(TitleProperty, value); }
}
public static readonly DependencyProperty TitleProperty =
DependencyProperty.Register("Title", typeof(string), typeof(Card), new UIPropertyMetadata(""));
}
and on MainWindow.xaml
<Objects:Card Grid.Column="1" Grid.Row="1" Title="Say Something Here"/>
The rectangles are rendering but my text is not rendering in the control
I have tested this by adding text without the binding which works fine. However the problem is at the binding. I want to have the ability to set the text object on main window through the use of a xaml tag but I cannot do this as it will not show me. Any help appreciated :)

The Text binding in the UserControl's XAML is missing a source object, which should be the UserControl instance.
One way to set the binding source to the UserControl instance is to set the RelativeSource property:
<TextBlock Text="{Binding Path=Title,
RelativeSource={RelativeSource AncestorType=UserControl}}" ... />
You may also set the x:Name attribute on the UserControl, and set the binding's ElementName:
<UserControl ... x:Name="self">
...
<TextBlock Text="{Binding Path=Title, ElementName=self}" ... />
...
</UserControl>

How to load usercontrol in Mainwindow in MVVM WPF?

I have a MainWindow.Xaml file. And one usercontrol PatientWindow.Xaml. How to load the patient window in mainwindow in MVVM architecture?
MainWindow.Xaml
<Window x:Class="PatientAdminTool.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="clr-namespace:PatientAdminTool.ViewModel"
xmlns:v="clr-namespace:PatientAdminTool.View"
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
ResizeMode="CanResizeWithGrip"
WindowStyle="None"
WindowState="Normal"
Title="PatientAdmin Tools"
Height="750"
Width="1400"
AllowsTransparency="True" MouseLeftButtonDown="OnMouseLeftButtonDown" BorderThickness="1" BorderBrush="#555252" >
<WindowChrome.WindowChrome>
<WindowChrome
CaptionHeight="0"
/>
</WindowChrome.WindowChrome>
</Window>
PatientWindow.xaml
Usercontrol window is mentioned in below
<UserControl x:Class="PatientAdminTool.View.PatientWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:vm="clr-namespace:PatientAdminTool.ViewModel"
xmlns:v="clr-namespace:PatientAdminTool.View"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300" >
<Grid >
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<DockPanel Grid.Row="0" LastChildFill="True" Height="40" Background="#646161" >
<StackPanel DockPanel.Dock="Left" Orientation="Horizontal">
<TextBlock Margin=" 10,5,0,0" HorizontalAlignment="Center" Text="Patients" FontSize="16" TextAlignment="Center" VerticalAlignment="Center" Foreground="#FFFFFF"/>
</StackPanel>
<StackPanel Margin="10,10,0,0" DockPanel.Dock="Right" Background="Transparent" Orientation="Vertical" HorizontalAlignment="Right" VerticalAlignment="Top" Width="50" >
<StackPanel Background="Transparent" Orientation="Horizontal" HorizontalAlignment="Right">
<Button Focusable="False" ToolTip="Close" VerticalAlignment="Center" Background="#646161" BorderThickness="0" BorderBrush="Transparent" Padding="-4" Click="Button_Click" >
<Button.Content>
<Grid Width="45" Height="23">
<TextBlock Foreground="White" Text="r" FontFamily="Marlett" FontSize="20" VerticalAlignment="Center" HorizontalAlignment="Center"/>
</Grid>
</Button.Content>
<Button.Template>
<ControlTemplate TargetType="Button">
<ContentPresenter Content="{TemplateBinding Content}"/>
</ControlTemplate>
</Button.Template>
</Button>
</StackPanel>
</StackPanel>
</DockPanel>
</Grid>
</UserControl>
So I need to load the patient window above of main window using MVVM. Here I need to write load event in corresponding View Model. Please help me to do this.

Just add a ControlPresenter at MainWindow.
<ContentPresenter Content="{Binding YouTypeHere}">
<ContentPresenter.Resources>
<DataTemplate DataType="{x:Type fristViewModel1Type}">
<youControlForViewModel1 />
</DataTemplate>
<DataTemplate DataType="{x:Type secondViewModel2Type}">
<youControlForViewModel2 />
</DataTemplate>
</ContentPresenter.Resources>
</ContentPresenter>
And you could change Views via binding different VM to ContentPresenter.

So you want to open a new child window using MVVM? I assume you would open it from MainWindowViewModel.
Solution 1: without strict MVVM
Sometimes its fine to open it directly from the ViewModel:
private void OnOpenPatientWindowCommandExecute()
{
var o = new PatientWindow();
o.ShowDialog();
}
For this you would have to change PatientWindow from UserControl to a Window.
Solution 2: strict MVVM
The solutions following strict MVVM are a little more complex. In the solution I write here you would have to use a Service, add it to your MainWindowViewModel and bind a control from the view to a Command in the ViewModel. Also, its written as if you are using Dependency Injection, that's why you see the service injected in the constructor. You can avoid this by just instantiating the service in the constructor.
MainWindowViewModel.cs
using Prism.Wpf.Commands; // For easy commands
using PatientAdminTool.Services; // Where you put your new service
public class MainWindowViewModel
{
private IShowDialogService _ShowDialogService;
public MainWindowViewModel(IShowDialogService showDialogService)
{
_ShowDialogService = showDialogService;
// Or do: _ShowDialogService = new ShowDialogService();
// But that's not a good practice and won't let you test
// this ViewModel properly.
OpenPatientWindowCommand = new DelegateCommand(OnOpenPatientWindowCommandExecute);
}
public ICommand OpenPatientWindowCommand { get; private set; }
private void OnOpenPatientWindowCommandExecute()
{
_ShowDialogService.ShowPatientWindow();
}
}
Services\IShowDialogService.cs
public interface IShowDialogService
{
void ShowPatientWindow();
void ShowOtherWindow();
// ...
}
Services\ShowDialogService.cs
public class ShowDialogService : IShowDialogService
{
public void ShowPatientWindow()
{
var patientWindowViewModel = new PatientWindowViewModel();
var patientWindow = new PatientWindow();
patientWindow.DataContext = patientWindowViewModel;
patientWindow.ShowDialog();
}
public void ShowOtherWindow()
{
// Other window ...
}
}
Finally, you make the connection in the View like this:
MainWindow.xaml
<Window
xmlns:vm="clr-namespace:PatientAdminTool.ViewModel">
<Window.DataContext>
<vm:MainWindowViewModel/>
</Window.DataContext>
<Grid>
<Button Command="{Binding OpenPatientCommand}">Open Patient</Button>
</Grid>
</Window>
Haven't tried it in Visual Studio yet but that's the idea.

If it's the only thing you are going to be displaying in the same window, just put your view in there like any other control:
<Window x:Class="PatientAdminTool.MainWindow"
xmlns:v="clr-namespace:PatientAdminTool.View"... >
<WindowChrome.WindowChrome>
<WindowChrome
CaptionHeight="0"/>
</WindowChrome.WindowChrome>
<v:PatientWindow/>
</Window>
Do you have a root ViewModel for your window? If so, you can bind to a PatientViewModel:
<v:PatientWindow DataContext="{Binding PatientViewModel}"/>
If not, it's common to set the first DataContext to a ViewModel in the code-behind like this:
<v:PatientWindow Name="PatientWindowView"/>
and:
public partial class Window
{
public MainWindow()
{
InitializeComponent();
PatientWindowView.DataContext = new PatientWindowViewModel();
}
}
If you want to display more than one View, use a ContentPresenter like Shakra has answered.
If you want to open a new window, use what Alberto Cardona López has suggested.

set deledate in ItemsControl ResourceDictionary

First, let me show you how my code is cut.
I have this code in a xaml UC (eventsUC.xaml) :
<UserControl x:Class="QuimeO.UserControls.Lists.EventsListUC"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:ToggleSwitch="clr-namespace:ToggleSwitch;assembly=ToggleSwitch"
mc:Ignorable="d"
Width="477"
>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<ScrollViewer HorizontalScrollBarVisibility="Disabled" Width="auto" VerticalScrollBarVisibility="Auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
<ItemsControl Grid.Row="0" BorderThickness="0" x:Name="eventsList" ScrollViewer.VerticalScrollBarVisibility="Auto" HorizontalContentAlignment="Stretch" ScrollViewer.HorizontalScrollBarVisibility="Disabled">
<ItemsControl.Resources>
<ResourceDictionary x:Name="eventslisttempplate" Source="EventsListTemplate.xaml" />
</ItemsControl.Resources>
</ItemsControl>
</ScrollViewer>...
My EventsListTemplate.xaml looks like this :
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Class="QuimeO.UserControls.Lists.EventsListTemplate"
xmlns:apiNamespace="clr-namespace:QuimeO.DBO"
>
<DataTemplate DataType="{x:Type apiNamespace:EventsDictionary}">
<StackPanel Orientation="Vertical">
<Border BorderBrush="LightGray" BorderThickness="0,0,0,1" Margin="0,5,0,0">
<TextBlock HorizontalAlignment="Right" Foreground="Gray" Text="{Binding FormatedDate}" FontSize="14"></TextBlock>
</Border>
<ListView Grid.Row="0" x:Name="eventsList" ItemsSource="{Binding Events}" BorderThickness="0" MouseDoubleClick="eventsList_MouseDoubleClick">
</ListView>
</StackPanel>
</DataTemplate>
</ResourceDictionary>
And my EventsListTemplate.xaml.cs code behind looks like this
public partial class EventsListTemplate : ResourceDictionary
{
public Delegate MainWindowControlPointer;
private void eventsList_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{
var ev = ((sender as ListView).SelectedItem as ListViewItem).DataContext as Event;
System.Diagnostics.Debug.WriteLine(ev.Name);
this.MainWindowControlPointer.DynamicInvoke(ev.Ancestors.Root, new Element() { Category = ev.Category, Id = ev.Id, Name = ev.Name });
}
}
When I click on an item of my listview in my template, it trigger the eventsList_MouseDoubleCkick and I can retrieve my event.
However, I would like to trigger an action in the UC where the template is created (first source code block).
To do that, I just want to create a delegate in my Template (technicaly, in a perfect world, something like "this.rd_eventslisttemplate.MainWindowControlPointer = ... "). But, I don't know how to do it or if this is even possible.

After encrypting your question for a while I think I got it.
There is a nice method called VisualTreeHelper.GetParent() which gets you the parent of a control in VisualTree.
Now to your problem when you catch your event in EventsListTemplate you will need to call GetParent() few times till you finally get the instance of your UserControl.
Thats it.

How to place an XAML usercontrol in a grid

I have the following main.xaml and usercontrol.
I need to place several times the user control on the 2nd row, 2nd column of the grid, By using visual studio it wont allow to drag and drop the user control, so I suppose I have to do it by code, I just dont know how
MainPage.xaml
<Grid HorizontalAlignment="Left" Height="768" VerticalAlignment="Top" Width="1366" x:Name="grid" Background="Black">
<Grid.RowDefinitions>
<RowDefinition Height="150"/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition Width="250"/>
</Grid.ColumnDefinitions>
<Border BorderBrush="White" BorderThickness="3" Grid.Column="1" Background="Red" CornerRadius="30"/>
<TextBlock x:Name="txtCountry" Grid.Column="1" TextWrapping="Wrap" FontSize="36" HorizontalAlignment="Center" VerticalAlignment="Center"/>
<TextBlock x:Name="txtTime" Grid.Row="1" TextWrapping="Wrap" FontSize="180" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Grid>
Usercontrol
<UserControl
x:Class="AlarmPro.TimeOnCity"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:AlarmPro"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="150"
d:DesignWidth="250">
<Grid Background="Black">
<Grid.RowDefinitions>
<RowDefinition Height="30"/>
<RowDefinition/>
</Grid.RowDefinitions>
<Border BorderBrush="#FFDE6A6A" BorderThickness="1" Grid.Row="0" Grid.Column="0" Background="#FFDC4646">
<TextBlock TextWrapping="Wrap" Text="TextBlock" HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="16"/>
</Border>
<Border BorderBrush="Black" BorderThickness="1" Grid.Row="1" Background="#FFAE4F00">
<TextBlock TextWrapping="Wrap" Text="TextBlock" HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="36"/>
</Border>
</Grid>
</UserControl>

Do you mean like this?
<my:UserControlName Grid.Column="2" Grid.Row="2" ... />
<my: in this case is the alias for the CLR namespace the UserControl resides in. It is defined at the top of your XAML, inside the <Window> or <UserControl> tag depending on context.
For example,
<Window ...
xmlns:my="clr-namespace:AssemblyName"
...
/>

MainPage.Xaml
<Page
x:Class="UserControlExample.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:UserControlExample"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Grid x:Name="MainContent" Background="Azure" >
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<ScrollViewer Grid.Row="1" HorizontalScrollBarVisibility="Hidden"
VerticalScrollBarVisibility="Hidden">
<local:UserControl1 x:Name="MyHelloWorldUserControl" Grid.Row="1" />
</ScrollViewer>
</Grid>
</Page>
UserControl1.xaml
<UserControl
x:Class="UserControlExample.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:UserControlExample"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="300"
d:DesignWidth="400">
<Grid Background="Bisque">
<StackPanel>
<StackPanel Orientation="Horizontal" Height="81">
<TextBlock Text="Your Name is" Foreground="Blue" FontSize="30" Margin="0,0,0,10"/>
<TextBox x:Name="Input" Background="White" Width="225" />
</StackPanel>
<Button Content="Click Me" Foreground="Brown" FontSize="30" Click="Button_Click"/>
<TextBlock x:Name="Output" FontSize="100"/>
</StackPanel>
</Grid>
</UserControl>

MainPage.xaml, I am binding a login UserControl
by using the namespace : xmlns:UC="clr-namespace:Test.Views" , since I have my usercontrol in Folder named "Views".
<ScrollViewer>
<UC:Login BtnLoginClick="Login_BtnLoginClick"/>
</ScrollViewer>
Login.cs
public partial class Login : UserControl {
public event EventHandler BtnLoginClick;
public Login()
{
InitializeComponent();
}
private void btnLogin_Click(object sender, RoutedEventArgs e)
{
string userName = txtUserName.Text;
string userPassword = txtUserPassword.Password.Trim();
if (userName != null && userName != string.Empty && userPassword != null && userPassword != string.Empty)
{
if (this.BtnLoginClick != null)
{
this.BtnLoginClick(this, e);
}
}
else
{
MessageBox.Show("Invalid username or password");
}
}
}
Finally, dont forgot to use the event handler in MainPage.xaml to capture the button clicked event from Login Usercontrol to do other actions.
MainPage.xaml
<UC:Login BtnLoginClick="Login_BtnLoginClick"/>
Here "BtnLoginClick" its an event Handler defined in the Login.xaml[User Control].
Create new event for this "BtnLoginClick" event as i created "Login_BtnLoginClick".
MainPage.cs
private void Login_BtnLoginClick(object sender, EventArgs e)
{
Messagebox.Show("Event captured successfully");
////Here you can add your stuffs...
}

For UWP, in UserControl.xaml, find the local namespace xmlns:local notation: xmlns:local="using:ProjectName.Folder" at the top (by convention, C# namespaces are named the same way as the folder that contains them, so folder also means namespace).
In MainPage.xaml, add a reference to this namespace. The reference prefix can be any name desired: for example, CustomPrefix, as in xmlns:CustomPrefix="using:ProjectName.Folder". Then, anywhere in MainPage.xaml, display the control by prefixing its name with <CustomPrefix:...>.
UserControl.xaml
<UserControl
xmlns:local="using:ProjectName.Folder">
MainPage.xaml
<Page
xmlns:CustomPrefix="using:ProjectName.Folder">
<CustomPrefix:UserControl />
</Page>
The project needs to be built to discard XAML errors in Visual Studio, otherwise the design view remains blank and the XAML has green squiggles.