I want to be able to change a property in my main window from my user controls view model.
This is the connection
- MainWindow
- I bind my property from its view model to my usercontrol
- MainWindowViewModel
- My property lies here, it does get updated when user control property changes
- UserControl1
- its dependency property that's binded to Main Window View Model returns a value from UserControlViewModel
- UserControl1ViewModel
- The logic that changes the property (which is supposed to update MainWindowViewModel) lies here.
I can do the binding between all of them, but the problem is when I update my property from the bottom layer (UserControlViewModel), it does not update my property neither in UserControl or in my MainWindowViewModel.
Here is all my code (I have also uploaded the project on my google drive)
MainWindow.xaml
<Window x:Class="WpfApplicationViewToViewModel.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:WpfApplicationViewToViewModel"
mc:Ignorable="d"
Title="MainWindow" Height="367" Width="624">
<StackPanel>
<local:UserControl1 TextInUserControl="{Binding DataContext.TextInMainWindowViewModel,
Mode=TwoWay, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}}">
</local:UserControl1>
<Button Content="Test MainWindow VM" Command="{Binding CommandTestMWVM}" ></Button>
<Separator></Separator>
</StackPanel>
</Window>
MainVindow.xaml.cs
using System.Windows;
namespace WpfApplicationViewToViewModel
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
this.DataContext = new MainWindowViewModel();
}
}
}
MainWindowViewModel.cs
using System;
using System.Windows;
using System.Windows.Input;
namespace WpfApplicationViewToViewModel
{
class MainWindowViewModel : ViewModelBase
{
public string TextInMainWindowViewModel
{
get
{
return _textInMainWindowViewModel;
}
set
{
_textInMainWindowViewModel = value;
RaisePropertyChanged("TextInMainWindowViewModel");
}
}
private string _textInMainWindowViewModel { get; set; }
//test button
public MainWindowViewModel()
{
_commandTestMWVM = new RelayCommand(new Action<object>(TestMWVM));
}
#region [Command] CommandTestMWVM
public ICommand CommandTestMWVM
{
get { return _commandTestMWVM; }
}
private ICommand _commandTestMWVM;
private void TestMWVM(object obj)
{
TextInMainWindowViewModel = TextInMainWindowViewModel + "MWVM";
MessageBox.Show("TextInMainWindowModel " + TextInMainWindowViewModel);
}
#endregion
}
}
UserControl1.xaml (includes just two buttons for testing purposes)
<UserControl x:Class="WpfApplicationViewToViewModel.UserControl1"
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:WpfApplicationViewToViewModel"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<StackPanel>
<Button Content="Test UC" Click="Button_Click"></Button>
<Button Content="Test UCVM" Command="{Binding CommandTestUCVM}" ></Button>
</StackPanel>
</UserControl>
UserControl1.xaml.cs
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
namespace WpfApplicationViewToViewModel
{
/// <summary>
/// Interaction logic for UserControl1.xaml
/// </summary>
public partial class UserControl1 : UserControl
{
private UserControl1ViewModel VM = new UserControl1ViewModel();
public UserControl1()
{
InitializeComponent();
this.DataContext = VM;
//http://stackoverflow.com/questions/15132538/twoway-bind-views-dependencyproperty-to-viewmodels-property
//does not work because breaks binding somewhere
//string propertyInViewModel = "TextInUserControlViewModel";
//var bindingViewMode = new Binding(propertyInViewModel) { Mode = BindingMode.TwoWay };
//this.SetBinding(TextInUserControlProperty, bindingViewMode);
}
//dependency property declaration
public static DependencyProperty TextInUserControlProperty =
DependencyProperty.Register("TextInUserControl",
typeof(string),
typeof(UserControl1)
);
public string TextInUserControl
{
get {
return (DataContext as UserControl1ViewModel).TextInUserControlViewModel;
}
set
{
(DataContext as UserControl1ViewModel).TextInUserControlViewModel = value;
this.SetValue(TextInUserControlProperty, value);
}
}
private void Button_Click(object sender, RoutedEventArgs e)
{
TextInUserControl = TextInUserControl + "UC";
MessageBox.Show("TextInUserControl : " + TextInUserControl);
}
}
}
UserControl1ViewModel.cs
using System;
using System.Windows;
using System.Windows.Input;
namespace WpfApplicationViewToViewModel
{
class UserControl1ViewModel : ViewModelBase
{
private string _textInViewModel;
public string TextInUserControlViewModel
{
get { return _textInViewModel; }
set {
_textInViewModel = value;
RaisePropertyChanged("TextInUserControlViewModel");
} }
//test button
public UserControl1ViewModel()
{
_commandTestUCVM = new RelayCommand(new Action<object>(TestUCVM));
}
#region [Command] CommandTestUCVM
public ICommand CommandTestUCVM
{
get { return _commandTestUCVM; }
}
private ICommand _commandTestUCVM;
private void TestUCVM(object obj)
{
TextInUserControlViewModel = TextInUserControlViewModel + "UCVM";
MessageBox.Show("TextInUserControlViewModel : " + TextInUserControlViewModel);
}
#endregion
}
}
Any help is really really appreciated because I've been trying to figure out this system (reading usercontrols viewmodel from mainwindow) for almost a week.
To make my question more clear:
TextInUserControl <=> TextInMainWindowViewModel : works succesfuly
TextInUserControl => TextInUserControlViewModel : works but when I change TextInUserControlViewModel, TextInUserControl doesn't get updated automatically.
Is there anyway I can let TextInUserControl know that TextInUserControlViewModel is changed?
