We Keep Coding

The name MainViewModel does not exist in the namespace "clr-namespace:LINQ3_Test_aus_LINQ2"

I get the error message which is written in the title.
My XAML looks like this:
<Window x:Class="LINQ3_Test_aus_LINQ2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:LINQ3_Test_aus_LINQ2"
Title="MainWindow" Height="450" Width="800">
<Window.DataContext>
<local:MainViewModel/>
</Window.DataContext>
<Grid>
<TextBox x:Name="txt_LiefNr" HorizontalAlignment="Left" Height="26" Margin="55,50,0,0" TextWrapping="Wrap" Text="{Binding LiefNr}" VerticalAlignment="Top" Width="125"/>
<TextBox x:Name="txt_LiefName" HorizontalAlignment="Left" Height="26" Margin="55,93,0,0" TextWrapping="Wrap" Text="{Binding LiefName}" VerticalAlignment="Top" Width="125"/>
<Button x:Name="btn_LiefNr" Content="Button" HorizontalAlignment="Left" Height="26" Margin="215,50,0,0" VerticalAlignment="Top" Width="116" Command="{Binding LookupCommand}"/>
</Grid>
and my MainViewModel.cs like this:
using GalaSoft.MvvmLight.Command;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
namespace LINQ3_Test_aus_LINQ2
{
public class MainViewModel : INotifyPropertyChanged
{
private string _liefNr;
private string _liefName;
public ICommand LookupCommand { get; set; }
public string LiefNr
{
get { return _liefNr; }
set
{
_liefNr = value;
OnPropertyChanged();
}
}
public string LiefName
{
get { return _liefName; }
set
{
_liefName = value;
OnPropertyChanged();
}
}
public MainViewModel()
{
LookupCommand = new RelayCommand(Lookup);
}
private void Lookup()
{
Excel.OpenFile();
LiefName = Excel.Fill(LiefNr);
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
}
I cant find a solution to this error thats why i am asking you. I have checked multiple times if something is wrong the the names, but there is not its all written correctly.

C# Databinding Textblock, PropertyChanged stays null

Im trying to change 2 textblocks with data binding. The propertyChanged is always null, so the ui wont update.
This is my model code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace MovieApp.Models
{
public class MovieModel : INotifyPropertyChanged
{
string original_title, overview;
public event PropertyChangedEventHandler PropertyChanged;
public string Original_Title {
get
{
return original_title;
}
set
{
original_title = value;
onPropertyChanged(nameof(Original_Title));
}
}
public string Overview
{
get
{
return overview;
}
set
{
overview = value;
onPropertyChanged(nameof(Overview));
}
}
protected void onPropertyChanged(string propertyName)
{
if(PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
//PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
}
The mainview.xaml.cs:
using MovieApp.API;
using MovieApp.Models;
using MovieApp.Processor;
using System.Windows;
namespace MovieApp
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
//private readonly MovieModel movieModel = new MovieModel();
public MainWindow()
{
InitializeComponent();
ApiCaller.InitializeClient();
// DataContext = movieModel;
}
private async void previousImageButton_Click(object sender, RoutedEventArgs e)
{
int id = 484718;
await MovieProcessor.LoadMovie(id);
}
private async void nextImageButton_Click(object sender, RoutedEventArgs e)
{
int id = 527774;
await MovieProcessor.LoadMovie(id);
}
}
}
and the maindwindow.xaml:
<Window x:Class="MovieApp.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:MovieApp.Models"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Window.Resources>
<local:MovieModel x:Key="movieModel" />
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Button x:Name="previousImageButton" Padding="15" Margin="15" Click="previousImageButton_Click">Previous</Button>
<StackPanel Grid.Row="1">
<TextBlock Text="{Binding Source={StaticResource movieModel}, Path=Original_Title}" ></TextBlock>
<TextBlock Text="{Binding Source={StaticResource movieModel}, Path=Overview }"></TextBlock>
</StackPanel>
<Button Grid.Row="2" x:Name="nextImageButton" Padding="15" Margin="15" Click="nextImageButton_Click">Next</Button>
</Grid>
</Window>
EDIT:
Added the movieprocessor code:
using MovieApp.API;
using MovieApp.Models;
using System;
using System.Net.Http;
using System.Threading.Tasks;
namespace MovieApp.Processor
{
class MovieProcessor
{
public static async Task<MovieModel> LoadMovie(int id)
{
string url = $"movie/{id}?api_key=77e7d2ef687aedca2119680778f1d619&language=en-US";
using (HttpResponseMessage response = await ApiCaller.httpClient.GetAsync(url))
{
if (response.IsSuccessStatusCode)
{
MovieModel movie = await response.Content.ReadAsAsync<MovieModel>();
Console.WriteLine(movie.Original_Title);
Console.WriteLine(movie.Overview);
return movie;
}
else
{
throw new Exception(response.ReasonPhrase);
}
}
}
}
}
I have no idea what could be wrong. I tried multiple things but nothing seemed to work for me. I tried adding datacontext but that didnt work either. I let it commented in my code so anyone can see it.

If your MovieProcess class sets the value of MovieModel.Original_Title and MovieModel.Overview property then you have to ensure that MovieProcess is accessing the same instance of MovieModel as your view (xaml).
Instead of using StaticResource movieModel assing DataContext in code behind.
private readonly MovieModel movieModel = new MovieModel();
public MovieProcessor MovieProcessor { get; set; }
public MainWindow()
{
InitializeComponent();
ApiCaller.InitializeClient();
DataContext = movieModel;
MovieProcessor = new MoviewProcessor(moviewModel);
}
Xaml
<StackPanel Grid.Row="1">
<TextBlock Text="{Binding Original_Title}" />
<TextBlock Text="{Binding Overview }" />
</StackPanel>
MovieProcessor class
public class MovieProcessor
{
private readonly MovieModel movieModel;
public MovieProcessor(MovieModel movieModel)
{
this.movieModel = movieModel;
}
public async Task LoadMovie(int id)
{
...
movieModel.Original_Title = <loaded_movie_title>;
movieModel.Overview = <loaded_movie_overview>;
...
}
}

I bind the command to the Buttons in the MovieProcessor to show data in Maindwindow with StaticResource movieModel, below is my code:
NotifyObject.cs
public class NotifyObject : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChange(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
MyCommand.cs
public class MyCommand : ICommand
{
private Func<object, bool> _canExecute;
private Action<object> _execute;
public event EventHandler CanExecuteChanged
{
add
{
if (_canExecute != null)
{
CommandManager.RequerySuggested += value;
}
}
remove
{
if (_canExecute != null)
{
CommandManager.RequerySuggested -= value;
}
}
}
public bool CanExecute(object parameter)
{
if (_canExecute == null) return true;
return _canExecute(parameter);
}
public void Execute(object parameter)
{
if (_execute != null && CanExecute(parameter))
{
_execute(parameter);
}
}
public MyCommand(Action<object> execute) : this(execute, null)
{
}
public MyCommand(Action<object> execute, Func<object, bool> canExecute)
{
_execute = execute;
_canExecute = canExecute;
}
}
MovieProcessor.cs
public class MovieProcessor:NotifyObject
{
private MovieModel vm;
public MovieModel VM
{
get { return vm; }
set
{
vm = value;
OnPropertyChange("VM");
}
}
public MovieModel LoadMovie(int id)
{
//....
}
private MyCommand _cmd1;
public MyCommand Cmd1
{
get
{
if (_cmd1 == null)
_cmd1 = new MyCommand(new Action<object>
(
o =>
{
int id = 484718;
LoadMovie(id);
}
));
return _cmd1;
}
}
private MyCommand _cmd2;
public MyCommand Cmd2
{
get
{
if (_cmd2 == null)
_cmd2 = new MyCommand(new Action<object>
(
o =>
{
int id = 527774;
LoadMovie(id);
}
));
return _cmd2;
}
}
}
MainWindow.xaml
<Window.Resources>
<local:MovieProcessor x:Key="movieModel" />
</Window.Resources>
<Grid >
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Button x:Name="previousImageButton" Padding="15" Margin="15" Command="{Binding Source={StaticResource movieModel}, Path=Cmd1}">Previous</Button>
<StackPanel Grid.Row="1">
<TextBlock Text="{Binding Source={StaticResource movieModel}, Path=VM.Original_Title}" ></TextBlock>
<TextBlock Text="{Binding Source={StaticResource movieModel}, Path=VM.Overview }"></TextBlock>
</StackPanel>
<Button Grid.Row="2" x:Name="nextImageButton" Padding="15" Margin="15" Command="{Binding Source={StaticResource movieModel}, Path=Cmd2}">Next</Button>
</Grid>

Binding Collection to ListBox [duplicate]

This question already has answers here:
How do I update an ObservableCollection via a worker thread?
(7 answers)
Closed 5 years ago.
I try to do some simple task (I guess so). I want to change GUI dynamically, from the for loop.
Let's see my XAML:
<Window x:Class="WpfApplication1.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">
<StackPanel Name="MyPanel">
<TextBlock Text="{Binding MyValue}"></TextBlock>
<Button Click="Button_Click">OK</Button>
<ListBox Name="myList" ItemsSource="{Binding MyCollection}" >
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Margin="10">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="20"/>
<ColumnDefinition Width="20"/>
</Grid.ColumnDefinitions>
<TextBlock Text="{Binding A}" Grid.Column="0"/>
<TextBlock Text="{Binding B}" Grid.Column="1"/>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
</Window>
As you can see, I have the Textblock that shows numbers, button that is starting the program and the listbox, that should show the collection items.
After click on the button, the first textblock (bindes MyValue) shows dynamic values, but on the list box I get the next error:
"This type of CollectionView does not support changes to its SourceCollection from a thread different from the Dispatcher thread."
I saw another answers for the error, but cannot understand how to implement it in my case.
Here the C# code:
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public static MyModel m;
public MainWindow()
{
m = new MyModel();
InitializeComponent();
MyPanel.DataContext = m;
}
bool flag = false;
private void Button_Click(object sender, RoutedEventArgs e)
{
flag = !flag;
Task.Factory.StartNew(() =>
{
for (int i = 0; i < 5000000; i++)
{
if (flag == false) break;
m.MyValue = i.ToString();
m.MyCollection.Add(new ChartPoint { A = i, B = 2 * i });
}
});
}
}
public class MyModel : INotifyPropertyChanged
{
private string myValue;
public ObservableCollection<ChartPoint> MyCollection { get; set; }
public MyModel()
{
MyCollection = new ObservableCollection<ChartPoint>();
}
public string MyValue
{
get { return myValue; }
set
{
myValue = value;
RaisePropertyChanged("MyValue");
}
}
private void RaisePropertyChanged(string propName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propName));
}
public event PropertyChangedEventHandler PropertyChanged;
}
public class ChartPoint
{
public int A { get; set; }
public int B { get; set; }
}
}
Thanks a lot!

I have changed the Button_Click code a bit, is this you want to achieve, please suggest:
private void Button_Click(object sender, RoutedEventArgs e)
{
flag = !flag;
var list = new List <ChartPoint>();
Task.Factory.StartNew(() =>
{
for (int i = 0; i < 50000000; i++)
{
if (flag == false) break;
m.MyValue = i.ToString();
Dispatcher.BeginInvoke(new Action(() =>
{
m.MyCollection.Add(new ChartPoint
{
A = i,
B = 2 * i
});
}),
DispatcherPriority.Background);
}
});
}

How to show a view using Catel

I am developing a simple app with Catel. I have previously used ReactiveUI and am having a little trouble getting started with Catel. I have a basic MainWindow. In there I have a toolbar with some buttons. When a button is selected I would like to show in the bottom pane of the application a user control (based on what they selected). So far I have one basic view that has a listview in it and then a view model behind it. I need help in figuring out how to show that view when the button is selected. Thank you for your help. Here is what I have so far. As you can see, when the 'ExecutePlayersButtonCommand' in the mainviewmodel is run, i want it to show the players view. I am not sure how to get this. I can get it to come up in a popup but that is not what i want. In reactiveui I can do it with the Router.Navigate function. Not sure how to do it here.
<catel:DataWindow xmlns:Controls="clr-namespace:FootballSim.Controls;assembly=FootballSim.Controls"
xmlns:RedfoxSoftwareCustomControls="clr-namespace:RedfoxSoftwareCustomControls;assembly=RedfoxSoftwareCustomControls"
x:Class="FootballSim.Views.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:catel="http://catel.codeplex.com"
xmlns:views="clr-namespace:FootballSim.Views"
Style="{StaticResource {x:Type Window}}"
ShowInTaskbar="True" ResizeMode="CanResize" SizeToContent="Manual"
WindowStartupLocation="Manual" WindowState="Maximized" Icon="/FootballSim;component/redfox_software_48x48.ico">
<!-- Resources -->
<catel:DataWindow.Resources>
</catel:DataWindow.Resources>
<!-- Content -->
<catel:StackGrid x:Name="LayoutRoot">
<catel:StackGrid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</catel:StackGrid.RowDefinitions>
<DockPanel>
<StackPanel DockPanel.Dock="Top">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="50" />
<RowDefinition Height="100*" />
</Grid.RowDefinitions>
<RedfoxSoftwareCustomControls:WpfCustomApplicationMenuBar x:Name="CustomMenuBar" Grid.Row="0" />
<StackPanel Grid.Row="1">
<Button HorizontalAlignment="Left" Command="{Binding PlayersButtonCommand}" Background="Transparent">
<StackPanel>
<Image Source="/FootballSim;component/Resources/People_white_48.png" Width="30"></Image>
<TextBlock Text="Players" Foreground="White" HorizontalAlignment="Center"/>
</StackPanel>
</Button>
</StackPanel>
<DockPanel LastChildFill="True" Grid.Row="2">
<ContentControl Content="{Binding contentObject}" />
<!--<views:PlayersView DataContext="{Binding PlayerProviders}" />-->
</DockPanel>
</Grid>
</StackPanel>
</DockPanel>
</catel:StackGrid>
</catel:DataWindow>
using Catel.Windows;
using FootballSim.Scripts;
using FootballSim.Services;
using FootballSim.ViewModels;
using System;
using System.ComponentModel;
using Catel.MVVM.Views;
using Catel.Windows.Data;
using Catel.MVVM;
namespace FootballSim.Views
{
public partial class MainWindow : DataWindow
{
private RedfoxMessage logger = new RedfoxMessage();
private PopulateDatabase database = new PopulateDatabase();
public MainWindow() : base(DataWindowMode.Custom)
{
try
{
InitializeComponent();
logger.LogMessage("Starting application.");
CustomMenuBar.AboutButtonClickEvent += CustomMenuBar_AboutButtonClickEvent;
}
catch (Exception e)
{
RedfoxMessage.LogMessage(e, NLog.LogLevel.Error);
}
}
private void CustomMenuBar_AboutButtonClickEvent(object sender, System.EventArgs args)
{
(DataContext as IMainWindowViewModel).AboutButtonCommand.Execute(null);
}
}
}
using Catel.Data;
using Catel.IoC;
using Catel.MVVM;
using Catel.MVVM.Services;
using FootballSim.Models;
using FootballSim.Scripts;
using FootballSim.Views;
using System.Collections.Generic;
using System.Windows;
namespace FootballSim.ViewModels
{
public interface IMainWindowViewModel
{
Command PlayersButtonCommand { get; }
Command AboutButtonCommand { get; }
List<Player> PlayerProviders { get; }
Player SelectedPlayerProvider { get; }
object ContentObject { get; }
}
/// <summary>
/// MainWindow view model.
/// </summary>
public class MainWindowViewModel : ViewModelBase, IMainWindowViewModel
{
//private readonly IUIVisualizerService _uiVisualizerService;
private PopulateDatabase _populateDatabase;
public static readonly PropertyData PlayerProvidersProperty = RegisterProperty("PlayerProviders", typeof(List<Player>));
public static readonly PropertyData SelectedPlayerProviderProperty = RegisterProperty("SelectedPlayerProvider", typeof(Player));
public Command PlayersButtonCommand { get; private set; }
public Command AboutButtonCommand { get; private set; }
public object ContentObject { get; set; }
public MainWindowViewModel() : base()
{
//var dependencyResolver = this.GetDependencyResolver();
//_uiVisualizerService = dependencyResolver.Resolve<IUIVisualizerService>();
_populateDatabase = new PopulateDatabase();
PlayerProviders = _populateDatabase.Players;
var pv = new PlayersView();
pv.DataContext = PlayerProviders;
ContentObject = pv;
PlayersButtonCommand = new Command(ExecutePlayersButtonCommand);
AboutButtonCommand = new Command(ExecuteAboutButtonCommand);
}
private void ExecutePlayersButtonCommand()
{
PlayerProviders = _populateDatabase.Players;
MessageBox.Show("Players");
}
private void ExecuteAboutButtonCommand()
{
var aboutView = new AboutView();
aboutView.ShowDialog();
}
public List<Player> PlayerProviders
{
get
{
return GetValue<List<Player>>(PlayerProvidersProperty);
}
set
{
SetValue(PlayerProvidersProperty, value);
}
}
public Player SelectedPlayerProvider
{
get
{
return GetValue<Player>(SelectedPlayerProviderProperty);
}
set
{
SetValue(SelectedPlayerProviderProperty, value);
}
}
//protected override void Initialize()
//{
// SelectedPlayerProvider = PlayerProviders[0];
//}
public override string Title { get { return "FootballSim"; } }
}
}
<catel:UserControl x:Class="FootballSim.Views.PlayersView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:catel="http://catel.codeplex.com"
xmlns:views="clr-namespace:FootballSim.Views"
xmlns:viewmodels="clr-namespace:FootballSim.ViewModels"
xmlns:models="clr-namespace:FootballSim.Models;assembly=FootballSim.Core">
<!-- Resources -->
<UserControl.Resources>
</UserControl.Resources>
<!-- Content -->
<catel:StackGrid>
<catel:StackGrid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</catel:StackGrid.RowDefinitions>
<Label Content="{Binding Title}" Foreground="White" Grid.Row="0" />
<Label Content="Here goes your real content" Foreground="White" Grid.Row="1"/>
<ListBox Grid.Row="2" ItemsSource="{Binding PlayersCollection}" SelectedItem="{Binding SelectedPlayer}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<Label Content="{Binding ColumnValue}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<!--<views:PlayersView Grid.Column="1" DataContext="{Binding SelectedPlayer}" />-->
</catel:StackGrid>
</catel:UserControl>
namespace FootballSim.Views
{
using Catel.Windows.Controls;
using FootballSim.ViewModels;
public partial class PlayersView : UserControl
{
public PlayersView()
{
InitializeComponent();
}
}
}
namespace FootballSim.ViewModels
{
using Catel.MVVM;
using FootballSim.Models;
using System.Collections.Generic;
/// <summary>
/// UserControl view model.
/// </summary>
public class PlayersViewModel : ViewModelBase, IPlayersViewModel
{
public List<Player> Players { get; protected set; }
public PlayersViewModel(List<Player> players) : base()
{
Players = players;
}
public override string Title { get { return "View model title"; } }
// TODO: Register models with the vmpropmodel codesnippet
// TODO: Register view model properties with the vmprop or vmpropviewmodeltomodel codesnippets
// TODO: Register commands with the vmcommand or vmcommandwithcanexecute codesnippets
}
}

There are several ways of navigating in Catel:
IUIVisualizerService => show other dialogs
INavigationService => navigate to pages / close application / etc
Maybe it's a good idea for you to read the getting started guide of Catel.

Freezing main window after adding some items from childwindow

I am working on Silverlight 4 with mvvm and WCF services.
Whenever I am adding items from child window to main window. But at the same time main window automatically going to disabling mode. I think main window automatically freezes.
ChildWindow ViewModel
public class AddFormFieldInformationViewModel : ViewModelBase
{
private FieldInformationViewModel _FieldInformationViewModel;
public FieldInformationViewModel FieldInformationViewModel
{
get { return _FieldInformationViewModel; }
set
{
_FieldInformationViewModel = value;
RaisePropertyChanged("FieldInformationViewModel");
}
}
public void MoveSave(object obj)
{ this.FieldInformationViewModel.SelectedFormFields = FieldInformationModel;
ResultHandler(true);
}
public Action ResultHandler { get; set; }
}
ChildWindow .xaml.cs file
public partial class AddExistingFormFieldCategoryView : ChildWindow
{
private AddFormFieldInformationViewModel vm;
public AddExistingFormFieldCategoryView()
{
InitializeComponent();
vm = new AddFormFieldInformationViewModel();
this.DataContext = vm;
vm.ResultHandler = result => { if (result) { Close(); } };
}
}
Main Window ViewModel
public class FieldInformationViewModel : ViewModelBase
{ private void executeOpenChildWindow(object parameter)
{
AddExistingFormFieldCategoryView cw = new AddExistingFormFieldCategoryView();
((AddFormFieldInformationViewModel)cw.DataContext).FieldInformationViewModel = this;
cw.Show();
}
}
After adding items from child window into main window, sometimes my main window is automatically freezing.

Hi this is a bug you are experiencing see the sample below. I the same issue and you have to manually enable the display of the main page:
private static void ShowError(string message, string details)
{
ErrorWindow error = new ErrorWindow(message, details);
error.Closed += new EventHandler(error_Closed);
error.Show();
}
static void error_Closed(object sender, EventArgs e)
{
Application.Current.RootVisual.SetValue(Control.IsEnabledProperty, true);
}

You can subclass the ChildWindow and explicitly set the RootVisual to enabled. Source
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
namespace DST_Common_Silverlight_Controls
{
/// <summary>
/// Bug in ChildWindow sometimes leaves app disabled.
/// </summary>
public class ChildWindowEx : ChildWindow
{
protected override void OnClosed(EventArgs e)
{
base.OnClosed(e);
Application.Current.RootVisual.SetValue(Control.IsEnabledProperty, true);
}
}
}
Then just use the new type instead of ChildWindow in xaml like this:
<slcommon:ChildWindowEx
x:Class="DST.AvSyncMonitor.Silverlight.Gui.ErrorWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:slcommon="clr-namespace:DST_Common_Silverlight_Controls;assembly=DST.Common.Silverlight.Controls"
xmlns:controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls"
Title="Error">
<Grid x:Name="LayoutRoot" Width="540">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<TextBlock x:Name="IntroductoryText" Grid.Row="0" Margin="0"
Text="An unknown error was encountered. Please contact your administrator for more information."/>
<StackPanel x:Name="ContentStackPanel" Grid.Row="2" Margin="0,6,0,0">
<TextBlock x:Name="LabelText" TextWrapping="Wrap" Margin="0,0,0,2"
Text="Error details"/>
<TextBox x:Name="ErrorTextBox" Height="90" TextWrapping="Wrap" IsReadOnly="True"
VerticalScrollBarVisibility="Auto"/>
</StackPanel>
<Button x:Name="OKButton" Grid.Row="3" Click="OKButton_Click"
Width="75" Height="23" HorizontalAlignment="Right" Margin="0,10,0,0"
TabIndex="0" Content="OK"/>
</Grid>
</slcommon:ChildWindowEx>