We Keep Coding

WPF Usercontrol Bindings with MVVM ViewModel not working

I've spent some time trying to solve this problem but couldn't find a solution.
I am trying to bind commands and data inside an user control to my view model. The user control is located inside a window for navigation purposes.
For simplicity I don't want to work with Code-Behind (unless it is unavoidable) and pass all events of the buttons via the ViewModel directly to the controller. Therefore code-behind is unchanged everywhere.
The problem is that any binding I do in the UserControl is ignored.
So the corresponding controller method is never called for the command binding and the data is not displayed in the view for the data binding. And this although the DataContext is set in the controllers.
Interestingly, if I make the view a Window instead of a UserControl and call it initially, everything works.
Does anyone have an idea what the problem could be?
Window.xaml (shortened)
<Window x:Class="Client.Views.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:Client.Views"
mc:Ignorable="d">
<Window.Resources>
<local:SubmoduleSelector x:Key="TemplateSelector" />
</Window.Resources>
<Grid>
<StackPanel>
<Button Command="{Binding OpenUserControlCommand}"/>
</StackPanel>
<ContentControl Content="{Binding ActiveViewModel}" ContentTemplateSelector="{StaticResource TemplateSelector}">
<ContentControl.Resources>
<DataTemplate x:Key="userControlTemplate">
<local:UserControl />
</DataTemplate>
</ContentControl.Resources>
</ContentControl>
</Grid>
</Window>
MainWindowViewModel (shortened)
namespace Client.ViewModels
{
public class MainWindowViewModel : ViewModelBase
{
private ViewModelBase mActiveViewModel;
public ICommand OpenUserControlCommand { get; set; }
public ViewModelBase ActiveViewModel
{
get { return mActiveViewModel; }
set
{
if (mActiveViewModel == value)
return;
mActiveViewModel = value;
OnPropertyChanged("ActiveViewModel");
}
}
}
}
MainWindowController (shortened)
namespace Client.Controllers
{
public class MainWindowController
{
private readonly MainWindow mView;
private readonly MainWindowViewModel mViewModel;
public MainWindowController(MainWindowViewModel mViewModel, MainWindow mView)
{
this.mViewModel = mViewModel;
this.mView = mView;
this.mView.DataContext = mViewModel;
this.mViewModel.OpenUserControlCommand = new RelayCommand(ExecuteOpenUserControlCommand);
}
private void OpenUserControlCommand(object obj)
{
var userControlController = Container.Resolve<UserControlController>(); // Get Controller instance with dependency injection
mViewModel.ActiveViewModel = userControlController.Initialize();
}
}
}
UserControlSub.xaml (shortened)
<UserControl x:Class="Client.Views.UserControlSub"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:Client.Views"
xmlns:viewModels="clr-namespace:Client.ViewModels"
mc:Ignorable="d">
<Grid>
<ListBox ItemsSource="{Binding Models}" SelectedItem="{Binding SelectedModel}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding Attr}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<StackPanel>
<Button Command="{Binding Add}">Kategorie hinzufügen</Button>
</StackPanel>
</Grid>
</UserControl>
UserControlViewModel (shortened)
namespace Client.ViewModels
{
public class UserControlViewModel : ViewModelBase
{
private Data _selectedModel;
public ObservableCollection<Data> Models { get; set; } = new ObservableCollection<Data>();
public Data SelectedModel
{
get => _selectedModel;
set
{
if (value == _selectedModel) return;
_selectedModel= value;
OnPropertyChanged("SelectedModel");
}
}
public ICommand Add { get; set; }
}
}
UserControlController (shortened)
namespace Client.Controllers
{
public class UserControlController
{
private readonly UserControlSub mView;
private readonly UserControlViewModel mViewModel;
public UserControlController(UserControlViewModel mViewModel, UserControlSub mView)
{
this.mViewModel = mViewModel;
this.mView = mView;
this.mView.DataContext = mViewModel;
this.mViewModel.Add = new RelayCommand(ExecuteAddCommand);
}
private void ExecuteAddCommand(object obj)
{
Console.WriteLine("This code gets never called!");
}
public override ViewModelBase Initialize()
{
foreach (var mod in server.GetAll())
{
mViewModel.Models.Add(mod);
}
return mViewModel;
}
}
}

MVVM Hierarchical Navigation tutorial StackOverFlow exception

I'm trying to reproduce a MVVM tutorial for WPF but applying it to UWP. But I've done everything in the tutorial I believe right the exact same code shown at the tutorial.
But when I ran the code I kept getting a StackOverflowException which is caused because the MainPageView keeps initializing again and again, until the exception is thrown.
The thing is I'm kinda knew at MVVM and I wish to master it, so can somebody please explain me why am I getting this?
I'll leave the code of each one of my classes and views.
This is my MainPageView.Xaml:
<Page
x:Class="MVVMHierarchiesDemo.MainPageView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:MVVMHierarchiesDemo"
xmlns:views="using:MVVMHierarchiesDemo.Views"
xmlns:viewmodel="using:MVVMHierarchiesDemo.ViewModel"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<!--Anytime the current view model is set to an instance of a CustomerListViewModel,
it will render out a CustomerListView with the ViewModel is hooked up. It’s an order ViewModel,
it'll render out OrderView and so on.
We now need a ViewModel that has a CurrentViewModel property and some logic and commanding
to be able to switch the current reference of ViewModel inside the property.-->
<Page.DataContext>
<local:MainPageView/>
</Page.DataContext>
<Page.Resources>
<DataTemplate x:Key="CustomerTemplate" x:DataType="viewmodel:CustomerListViewModel">
<views:CustomerListView/>
</DataTemplate>
<DataTemplate x:Key="OrderTemplate" x:DataType="viewmodel:OrderViewModel">
<views:OrderView/>
</DataTemplate>
</Page.Resources>
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid x:Name="NavBar"
Grid.Row="0">
<Button Content="Customers"
Command="{Binding NavCommand}"
CommandParameter="customers"
Grid.Column="0"
Grid.Row="0"/>
<Button Content="Orders"
Command="{Binding NavCommand}"
CommandParameter="orders"
Grid.Column="2"
Grid.Row="0"/>
</Grid>
<Grid x:Name="MainContent"
Grid.Row="1">
<ContentControl Content="{Binding CurrentViewModel}"/>
</Grid>
</Grid>
</Page>
This is my code-behind MainPageView.xaml.cs - here is where the StackoverflowException is thrown in the constructor it keeps calling it.
using Windows.UI.Xaml.Controls;
// The Blank Page item template is documented at https://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409
namespace MVVMHierarchiesDemo
{
/// <summary>
/// An empty page that can be used on its own or navigated to within a Frame.
/// </summary>
public sealed partial class MainPageView : Page
{
public MainPageView()
{
this.InitializeComponent();
}
}
}
This is my BindableBase.cs as the tutorial shows:
using System.ComponentModel;
using System.Runtime.CompilerServices;
namespace MVVMHierarchiesDemo
{
/*The main idea behind this class is to encapsulate the INotifyPropertyChanged implementation
* and provide helper methods to the derived class so that they can easily trigger the appropriate notifications.
* Following is the implementation of BindableBase class.*/
public class BindableBase : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged = delegate { };
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
protected virtual void SetProperty<T>(ref T member, T val, [CallerMemberName]string propertyName = null)
{
if (object.Equals(member, val))
return;
member = val;
OnPropertyChanged(propertyName);
}
}
}
This is MyCommand.cs or better known as the relay command pattern:
using System;
using System.Windows.Input;
namespace MVVMHierarchiesDemo
{
/* Now it's time to actually start doing some view switching using our CurrentViewModel property.
* We just need some way to drive the setting of this property. And we're going to make it so that
* the end user can command going to the customer list or to the order view. First add a new class
* in your project which will implement the ICommand interface. Following is the implementation of
* ICommand interface.*/
public class MyCommand<T> : ICommand
{
Action<T> _TargetExecuteMethod;
Func<T, bool> _TargetCanExecuteMethod;
public MyCommand(Action<T> targetExecuteMethod)
{
_TargetExecuteMethod = targetExecuteMethod;
}
public MyCommand(Action<T> targetExecuteMethod, Func<T,bool> targetCanExecuteMethod)
{
_TargetExecuteMethod = targetExecuteMethod;
_TargetCanExecuteMethod = targetCanExecuteMethod;
}
public event EventHandler CanExecuteChanged = delegate { };
public void RaiseCanExecuteChanged()
{
CanExecuteChanged?.Invoke(this, EventArgs.Empty);
}
bool ICommand.CanExecute(object parameter)
{
if (_TargetCanExecuteMethod != null)
{
T tparam = (T)parameter;
return _TargetCanExecuteMethod(tparam);
}
if (_TargetExecuteMethod != null)
return true;
return false;
}
void ICommand.Execute(object parameter)
{
if(_TargetExecuteMethod!=null)
{
T tparam = (T)parameter;
_TargetExecuteMethod(tparam);
}
}
}
}
This is my usercontrol for OrdersView.xaml:
<UserControl
x:Class="MVVMHierarchiesDemo.Views.OrderView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:MVVMHierarchiesDemo.Views"
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>
<TextBlock Text="Order View"/>
</Grid>
</UserControl>
This is my user control CustomerListView.xaml:
<UserControl
x:Class="MVVMHierarchiesDemo.Views.CustomerListView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:MVVMHierarchiesDemo.Views"
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>
<TextBlock Text="Customer List View"/>
</Grid>
</UserControl>
This is my OrderViewModel:
namespace MVVMHierarchiesDemo.ViewModel
{
/*Derive all of your ViewModels from BindableBase class.*/
public class OrderViewModel : BindableBase
{
}
}
This is my CustomerViewModel:
namespace MVVMHierarchiesDemo.ViewModel
{
/*Derive all of your ViewModels from BindableBase class.*/
public class CustomerListViewModel : BindableBase
{
}
}
Finally this is my MainPageViewModel:
namespace MVVMHierarchiesDemo.ViewModel
{
/*Derive all of your ViewModels from BindableBase class.*/
public class MainPageViewModel : BindableBase
{
public MainPageViewModel()
{
NavCommand = new MyCommand<string>(OnNavigation);
}
private CustomerListViewModel _customerListViewModel = new CustomerListViewModel();
private OrderViewModel _orderViewModel = new OrderViewModel();
private BindableBase _currentViewModel;
public BindableBase CurrentViewModel
{
get
{
return _currentViewModel;
}
set
{
SetProperty(ref _currentViewModel, value);
}
}
public MyCommand<string> NavCommand { get; private set; }
private void OnNavigation(string destination)
{
switch (destination)
{
case "orders":
{
CurrentViewModel = _orderViewModel;
break;
}
case "customers":
default:
CurrentViewModel = _customerListViewModel;
break;
}
}
}
}
and lastly I think the MainPageView is the one causing the infinite looping but I don't understand why?
If somebody could be so kind to tell me what I am doing wrong on UWP?
Also I could use MVVM Light or MVVMCross I'm not interested on those solutions I want to learn MVVM by hand and later on i might check those frameworks.

It's because in your MainPageView.xaml you have this:
<Page.DataContext>
<local:MainPageView/>
</Page.DataContext>
So every MainPageview creates a nested MainPageView as its DataContext. These are created until you blow the stack.
I think you meant to put a MainPageViewModel in here.

Passing parameter via Binding to UserConrol DependencyProperty

I have custom user control with the only property - SubHeader.
<UserControl x:Class="ExpensesManager.TopSection"
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"
DataContext="{Binding RelativeSource={RelativeSource Self}}"
mc:Ignorable="d">
<StackPanel>
<Label Name="Header" Content="Constant header text" Style="{StaticResource Header}"/>
<Label Name="SubHeader" Content="{Binding SubHeaderText}" Style="{StaticResource SubHeader}"/>
</StackPanel>
public partial class TopSection : UserControl
{
public TopSection()
{
this.InitializeComponent();
}
public static readonly DependencyProperty SubHeaderTextProperty =
DependencyProperty.Register("SubHeaderText", typeof(string), typeof(TopSection));
public string SubHeaderText
{
get { return (string)GetValue(SubHeaderTextProperty); }
set { SetValue(SubHeaderTextProperty, value); }
}
}
There are two usages in xaml. First with the constant text:
...
<my:TopSection SubHeaderText="Constant text"/>
...
Another one using binding:
<Page x:Class="MyNamespace.MyPage"
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:my="clr-namespace:My"
mc:Ignorable="d"
DataContext="{Binding RelativeSource={RelativeSource Self}}">
...
<my:TopSection SubHeaderText="{Binding MyModel.SubHeaderText}"/>
...
</Page>
My page code behind:
public partial class MyPage : Page
{
private MyModel myModel;
public MyModel MyModel
{
get
{
return this.myModel?? (this.myModel = new MyModel());
}
}
public MyPage(MyEntity entity)
{
this.InitializeComponent();
this.MyModel.MyEntity = entity;
}
}
MyModel code:
public class MyModel : NotificationObject
{
private MyEntity myEntity;
private string subHeaderText;
public MyEntity MyEntity
{
get
{
return this.myEntity;
}
set
{
if (this.myEntity!= value)
{
this.myEntity= value;
this.RaisePropertyChanged(() => this.MyEntity);
this.RaisePropertyChanged(() => this.SubHeaderText);
}
}
}
public string SubHeaderText
{
get
{
return string.Format("Name is {0}.", this.myEntity.Name);
}
}
}
The problem is that second one doesn't work. If I pass the constant text - it is displayed, if I use binding to the other property - nothing is displayed.
Does anybody knows what's wrong with the code? Thanks.

The problem is you set DataContext on the UserControl element. It will cause the following binding
<my:TopSection SubHeaderText="{Binding MyModel.SubHeaderText}"/>
to be relative to that DataContext, which is UserControl itself - so it cannot find the value.
To fix this, I suggest you not set DataContext on the UserControl, but the StackPanel inside:
<UserControl x:Class="ExpensesManager.TopSection"
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">
<StackPanel DataContext="{Binding RelativeSource={RelativeSource AncesterType=UserControl}}">
<Label Name="Header" Content="Constant header text" Style="{StaticResource Header}"/>
<Label Name="SubHeader" Content="{Binding SubHeaderText}" Style="{StaticResource SubHeader}"/>
</StackPanel>
Many people set DataContext on UserControl but that's really BAD. When you use the UserControl later, you have no idea the DataContext is actually set internally and will not respect the outside DataContext - really confusing. This rule also applies to other properties.

MyModel is a property in your DataContext? Try to check what object is your DataContext. If your data context is an object of your class MyModel you doesn't need the MyModel. part in your binding.
This kind of bindings always are to objects in your data context.
Hope this tips helps.

Declare your UserControl like this:
<my:TopSection
x:Name="myControl">
Then change your binding to this:
<my:TopSection SubHeaderText="{Binding MyModel.SubHeaderText, ElementName=myControl}"/>

You didn't set the Model in your UserControl
public partial class TopSection : UserControl
{
public class SampleViewModel { get; set; }
public TopSection()
{
this.InitializeComponent();
this.DataContext = new SampleViewModel();
}
public static readonly DependencyProperty SubHeaderTextProperty =
DependencyProperty.Register("SubHeaderText", typeof(string), typeof(TopSection));
public string SubHeaderText
{
get { return (string)GetValue(SubHeaderTextProperty); }
set { SetValue(SubHeaderTextProperty, value); }
}
}
Update
Since you don't want Model to known to the View. Create a ViewModel
public class SampleViewModel : NotificationObject
{
public class MyModel { get; set; }
public class SampleViewModel()
{
MyModel = new MyModel() { SubHeaderText = "Sample" };
RaisePropertyChange("MyModel");
}
}

Binding is not working on custom user control's dependency property

I've been working at this for awhile and seeming to not be able to find any good answers to my problem. I'm using a custom control that has custom dependency properties and in my main app I am binding to those propertys with my viewmodel that is seen through a viewmodel locator using mvvmlight. my question is why is the binding not updating nor seeing the correct datacontext?
Code:
User Control Xaml:
<UserControl x:Name="zKeyBoard"
x:Class="ZLibrary.ZKeyBoard"
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"
DataContext="{Binding RelativeSource={RelativeSource Self}}"
d:DesignHeight="768" d:DesignWidth="1024">
<Grid>
<TextBox TextWrapping="Wrap" Text="{Binding zDisplayText}" />
<Label Content="{Binding zBoxToEdit}"/>
</Grid>
</UserControl>
Things I have Tried In The User Control Xaml Already:
<TextBox TextWrapping="Wrap" Text="{Binding zDisplayText, ElementName=zKeyBoard}" />
<Label Content="{Binding zBoxToEdit, ElementName=zKeyBoard}"/>
User Control C#:
using System.ComponentModel;
namespace ZLibrary
{
public partial class ZKeyBoard : UserControl, INotifyPropertyChanged
{
public ZKeyBoard()
{
InitializeComponent();
}
public string zBoxToEdit
{
get { return (string)GetValue(zBoxToEditProperty); }
set { SetValue(zBoxToEditProperty, value); }
}
public static readonly DependencyProperty zBoxToEditProperty =
DependencyProperty.Register("zBoxToEdit", typeof(string), typeof(ZKeyBoard), new UIPropertyMetadata(""));
public string zDisplayText
{
get { return (string)GetValue(zDisplayTextProperty); }
set { SetValue(zDisplayTextProperty, value); }
}
public static readonly DependencyProperty zDisplayTextProperty =
DependencyProperty.Register("zDisplayText", typeof(string), typeof(ZKeyBoard), new UIPropertyMetadata(""));
}
}
Things I have already tried in the user control C#:
public string zBoxToEdit
{
get;
set;
}
public string zDisplayText
{
get;
set;
}
Here is the Project Files Where the User Control Is Being Used:
APP.xaml:
<Application x:Class="WpfApplication1.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:vm="clr-namespace:Sandstorm.ViewModel"
mc:Ignorable="d"
StartupUri="Main.xaml">
<Application.Resources>
<ResourceDictionary>
<vm:ViewModelLocator x:Key="Locator" d:IsDataSource="True" />
</ResourceDictionary>
</Application.Resources>
</Application>
The ViewModel Locator:
using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.Ioc;
using Microsoft.Practices.ServiceLocation;
namespace Sandstorm.ViewModel
{
class ViewModelLocator
{
public ViewModelLocator()
{
ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);
SimpleIoc.Default.Register<KeyBoardViewModel>(() =>
{
return new KeyBoardViewModel();
});
}
public KeyBoardViewModel KeyBoardViewModel
{
get { return ServiceLocator.Current.GetInstance<KeyBoardViewModel>(); }
}
public static void Cleanup()
{
// TODO Clear the ViewModels
}
}
}
The Xaml The User Control Is Being Used In:
<Page x:Name="keyboard_Frame"
x:Class="Sandstorm.keyBoard"
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:ZControls="clr-namespace:ZLibrary;assembly=ZLibrary"
DataContext="{Binding KeyBoardViewModel, Source={StaticResource Locator}}"
mc:Ignorable="d"
d:DesignHeight="768" d:DesignWidth="1024"
ShowsNavigationUI="False"
Title="KeyBoard">
<Grid>
<ZControls:ZKeyBoard zBoxToEdit="{Binding boxToEdit}" zDisplayText="{Binding keyboardEntry}" />
</Grid>
</Page>
When This Xaml is ran as is This Way It Throws an error in the console that says it can not find the binding property of either boxToEdit or keyboarEntry and it refrences the original ZKeyBoard Name as The place it can not be found... So I added this:
<ZControls:ZKeyBoard zBoxToEdit="{Binding boxToEdit, RelativeSource={RelativeSource Mode=TemplatedParent}}" zDisplayText="{Binding keyboardEntry, RelativeSource={RelativeSource Mode=TemplatedParent}}" />
Which caused the error to go away which I assume meant that it could find the viewmodel yet still nothing happened.
And Finally The View Model:
using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.Command;
using System.ComponentModel;
namespace Sandstorm.ViewModel
{
class KeyBoardViewModel : ViewModelBase, INotifyPropertyChanged
{
private string _keyboardEntry;
private string _boxToEdit;
public KeyBoardViewModel()
{
_boxToEdit = "yay";
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this,
new PropertyChangedEventArgs(propertyName));
}
}
public string keyboardEntry
{
get { return this._keyboardEntry; }
set
{
if (this._keyboardEntry != value)
{
this._keyboardEntry = value;
this.OnPropertyChanged("keyboardEntry");
Console.Out.WriteLine(this._keyboardEntry);
}
}
}
public string boxToEdit
{
get { return this._boxToEdit; }
set
{
if (this._boxToEdit != value)
{
this._boxToEdit = value;
this.OnPropertyChanged("boxToEdit");
Console.Out.WriteLine(this._boxToEdit);
}
}
}
}
}
One Thing I noticed was that I can Not See The Console.out.writeline doing anything which to me means it is not setting at all. so lots of big questions as to why this is not working. Any Help on this would be amazing! it probably is something small and stupid but a second pair of eyes on this will probably notice it faster than me.

Simple answer:
Don't set the DataContext to self.
Problem resolved

Creating a single controller for multiple WPF Pages

I'm very new to WPF and a beginner in C#.NET. I'm currently making an application where there will be many pages and the trigger to change the page is hand gesture using Kinect SDK (the trigger method is not relevant for this question). Normally when a WPF file is created, there will be a similarly named .cs file attached to it, which acts somewhat like a controller. However, I need multiple WPF files/pages to be controlled only by a single controller .cs file. How do I achieve that? Thanks for viewing my question and your answer will be very appreciated :)

You probably want to write a class that contains your 'controller' code and reference it from your WPF UserControls / Pages.
In a new file:
public class MyController
{
public void DoThings(object parameter)
{
// stuff you want to do
}
}
and then inside your UserControl code-behind class:
public partial class MyWpfControl : UserControl
{
private MyController controller;
public MyWpfControl
{
this.controller = new MyController();
}
}
and finally, tie your events back to the controller's method:
private void OnGesture(object sender, EventArgs e)
{
// call the method on the controller, and pass whatever parameters you need...
this.controller.DoThings(e);
}

The code behind is really part of the view and isn't really analogous to a controller and generally there shouldn't be much code in them. Typically you would want most of your logic between your "View Model" which serves as an abstraction of the view and "Model" which serves as an abstraction of the business logic that your UI is interacting with.
In this light what I think you really want is a View Model(VM) that controls multiple views. This is a fairly typical scenario and the preferred method (IMO anyway) is to have a hierarchical view model that has a top level the application model and a number of sub VMs that represent different components within your UI, though you can bind everything to your top level VM if you really want to.
To do this we would first define our view model like so
public interface IGestureSink
{
void DoGesture();
}
public class MyControlVM : INotifyPropertyChanged, IGestureSink
{
public event PropertyChangedEventHandler PropertyChanged = delegate { };
private ApplicationVM parent;
public MyControlVM(ApplicationVM parent)
{
this.Name = "my user control";
this.parent = parent;
parent.PropertyChanged += (s, o) => PropertyChanged(this, new PropertyChangedEventArgs("Visible"));
}
public String Name { get; set; }
public bool Visible { get { return parent.ControlVisible; } }
public void DoGesture()
{
parent.DoGesture();
}
}
public class ApplicationVM : INotifyPropertyChanged, IGestureSink
{
public event PropertyChangedEventHandler PropertyChanged = delegate { };
public ApplicationVM()
{
this.ControlVM = new MyControlVM(this);
this.ControlVisible = false;
}
public MyControlVM ControlVM { get; private set; }
public bool ControlVisible {get; set;}
public void DoGesture()
{
this.ControlVisible = !this.ControlVisible;
PropertyChanged(this, new PropertyChangedEventArgs("ControlVisible"));
}
}
and then all we need to do is to build a user control
<UserControl x:Class="WpfApplication2.MyControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Grid Background="LightBlue">
<Label Content="{Binding Name}"/>
</Grid>
</UserControl>
and page
<Window xmlns:my="clr-namespace:WpfApplication2" x:Class="WpfApplication2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" />
</Window.Resources>
<Grid>
<my:MyControl Width="200" Height="200" x:Name="myUserControl" DataContext="{Binding ControlVM}" Visibility="{Binding Visible,Converter={StaticResource BooleanToVisibilityConverter}}"/>
<Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="222,262,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" />
</Grid>
</Window>
That use it. The only thing that we need in our code behind is a constructor that sets up the page VM and wiring from our button to the view model.
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
this.DataContext = new ApplicationVM();
}
private void button1_Click(object sender, RoutedEventArgs e)
{
((IGestureSink)(this.DataContext)).DoGesture();
}
}
If you wanted to use a monolithic view model instead you would use this Instead of binding the DataContext to ControlVM:
<my:MyControl Width="200" Height="200" x:Name="myUserControl" DataContext="{Binding DataContext}" Visibility="{Binding ControlVisible,Converter={StaticResource BooleanToVisibilityConverter}}"/>