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Hybrid MVVM implementation for a PropertyGrid (in DevExpress)

I need your help! Following is basically what I have in my main XAML view :
<Button x:Name="button1" Content= "{Binding Customer1, Mode=TwoWay}" Margin="271,52,103,106" Click="button1_Click" />
The code-behind of the main XAML (Code-behind, since it's not a 100% pure MVVM, and a rather hybrid one) goes like this :
public MainWindow()
{
InitializeComponent();
this.DataContext = new MyViewModel();
}
private void button1_Click(object sender, RoutedEventArgs e)
{
DXDialog d = new DXDialog("Information", DialogButtons.OkCancel,true);
d.Content = new PropertyGrid();
d.SizeToContent = System.Windows.SizeToContent.WidthAndHeight;
d.Owner = this;
d.WindowStartupLocation = System.Windows.WindowStartupLocation.CenterOwner;
var result = d.ShowDialog();
if (result == true)
{
}
}
As you can see, I have a Button whose content is bound to a String property in the ViewModel Class. Upon Clicking the button, I'm opening a DXDialog which contains a PropertyGrid with the Properties of the ViewModel class. Let me show you my ViewModel Class below :
public class MyViewModel : ViewModelBase, INotifyPropertyChanged
{
Customer currentCustomer;
protected string _customer1;
public string Customer1 {
get { return this._customer1; }
set { this.SetProperty(ref this._customer1, value, "Customer1"); }
}
public MyViewModel()
{
//Customers = new ObservableCollection<Customer>();
//Customers.Add(new Customer() { Name = "Name1" });
Customer1 = "ABC";
}
}
In the Dialog I'm being able to edit the value of the property but don't yet know how I can save it in a way that it immediately reflects even on the button of the main View {Reflects everywhere it must be bound to, I mean}. I can see the execution coming to the following line in the main code behind
if (result == true)
{
}
But I don't know how to get the edited values and plug them into the right place.
Basically, My requirement is to have multiple controls (Buttons, in this case) bound to multiple instances of a ViewModel class, and then, upon clicking the buttons, I should be able to edit those specific ViewModel instances inside the PropertyGrid of the DXDialogue, and after clicking "Ok", the changes should reflect on the relevant buttons as well.
-Ron

To display ViewModel's properties in the PropertyGrid, assign the ViewModel to its SelectedObject property,and make sure that the ShowProperties option is set to All.
Changes will be reflected in buttons bound to the ViewModel only of you use one and the same ViewModel instance in the main and the dialog windows.
var grid = new PropertyGrid();
grid.SelectedObject = this.DataContext;
grid.ShowProperties = ShowPropertiesMode.All;
d.Content = grid;

Databinding with unnamed textboxes and listbox

I have been taught lately when using WPF and databinding it is good practice to not name any of the fields but only to associate them with the properties in the other classes. My problem right now is how do I add the data from 3 textboxes (the user enters), save the binded information to the model which then posts the account information into the listbox on the side. I need to add the data to my model. My code from main.xaml is below:
<ListBox ItemsSource="{Binding Path=Files}" SelectedItem="{BindingPath=CurrentItem}" />
<TextBox Text="{Binding Path=bankaccount}"/>
<TextBox Text="{Binding Path=accountnumber}"/>
<TextBox Text="{Binding Path=accounttype}"/>
<Button Content="Save Data To Listbox" Click="Save_Click"/>
Now I will show my FileModel class which holds all of my properties which will be from the textboxes
private short _BankAccount;
private long _AccountNumber;
private char _AccountType;
public short bankaccount{ get { return _BankAccount;} set {_BankAccount= value; Notify("bankaccount"); } }
public long accountnumber{ get { return _AccountNumber;} set {_AccountNumber= value; Notify("accountnumber"); } }
public char accounttype{ get { return _AccountType;} set{_AccountType= value; Notify("accounttype"); } }
I use a class called ProgramModel As my middle point between the Mainpage and my FileModel page and here is that code:
public class ProgramModel : INotifyPropertyChanged
{
public ObservableCollection<FileModel> Files { get; set; }
private FileModel _currentItem;
public FileModel CurrentItem { get { return _currentItem; } set { _currentItem = value; Notify("CurrentItem"); } }
public ProgramModel()
{
Files = new ObservableCollection<FileModel>();
}
And to finish it off I have my mainpage:
internal partial class MainWindow
{
public ProgramModel Model { get; set; }
private ViewSettings _viewSettings = new ViewSettings();
public MainWindow()
{
InitializeComponent();
this.DataContext = Model = new ProgramModel();
}
private void Save_Click(object sender, RoutedEventArgs e)
{
FileModel filemodel = new FileModel();
Model.Files.Add(new FileModel( filemodel.bankaccount, filemodel.accountnumber, filemodel.accounttype));
}
I feel like I am adding to the Files Collection incorrectly from the save button event. If you guys can help me out that would be great! All 3 textboxes and the listbox are on the Main page. Let me know if you have any questions. Also, this is a learning experience so let me know if I posted too much code or not enough. Thanks!

You read the values from a new FileModel instance instead of from what is bound to the view. Code should be this:
Model.Files.Add(new FileModel
(
Model.CurrentItem.bankaccount,
Model.CurrentItem.accountnumber,
Model.CurrentItem.accounttype
));
Make sure CurrentItem is actually initialized with an instance, don't see that in your code. Also, you could use a command here and have all the relevant logic in your bound view model without the need for the event.
Also, right now you bind the current item to the selected item in the ListBox, this will modify an existing instance instead. Not sure if this is intended. If you want those fields to be for input of new instances don't bind the ListBox to it.

I'm not going to answer your question directly because implementing proper data binding will take a bit of code to do so.
Using proper data binding, it is possible to have almost no code behind on your view.cs! (Specially if you start using frameworks)
Please take a look on A Simple MVVM Example for you to follow good practice.
By following this example, you will see that you can also use data binding on buttons and other controls.
Your View Model which is ProgramModel : INotifyPropertyChanged should handle all the work (data processing).
Your model should not handle the UI update notifications thus,
public short bankaccount{ get { return _BankAccount;} set {_BankAccount= value; Notify("bankaccount"); } }
will be moved to the ProgramModel (View Model).
Save_Click method will also be converted into an ICommand and be binded to the button in view like <Button Content="Save Data To Listbox" Command="{Binding SaveExec}"/>
The point is, if you are studying data binding, you should implement it right. Hope you understand...
In the end, it is possible for your Main.cs to only be..
internal partial class MainWindow
{
public MainWindow()
{
InitializeComponent();
this.DataContext = new ProgramModel();
}
}

Just a small change and it should work . Change Your bindings as shown below for the TextBoxes.
<TextBox Text="{Binding Path=CurrentItem.bankaccount}"/>
<TextBox Text="{Binding Path=CurrentItem.accountnumber}"/>
<TextBox Text="{Binding Path=CurrentItem.accounttype}"/>

View Model not updating UI when inside constructor

I have a feeling that my view isn't being updated because the NotifyPropertyChanged event is firing prior to the UI being constructed but I don't know how to overcome this.
I am not really posting code for analysis because I know that the databindings work. They just fail during the construction of the page.
I am strictly posting it so you can get an idea of what I am talking about.
public Obj1 SelectedObj1
{
get { return _SelectedObj1; }
set { _SelectedObj1 = value; NotifyPropertyChanged("SelectedObj1"); }
}
public Obj2 SelectedObj2
{
get { return _SelectedObj2; }
set { _SelectedObj2= value; NotifyPropertyChanged("SelectedObj2"); }
}
public Obj3 SelectedObj3
{
get { return _SelectedObj3; }
set { _SelectedObj3 = value; NotifyPropertyChanged("SelectedObj3"); }
}
Inside my constructor
public constructor(){
BuildFakeData();
SelectedObj1 = observableCollection[0];
SelectedObj2 = SelectedObj1.obj2s.Count > 0 ? SelectedObj1.obj2s[0] : null;
SelectedObj3 = SelectedObj2.obj3s.Count > 0 ? SelectedObj2.obj3s[0] : null;
}
My question is, when you are doing MVVM, if you set bound properties in the constructor, say for a DataGrid selected Row, will it populate or is it failing because the XAML isn't built yet?
Here is where the datacontext is created in the view
<Window.Resources>
<vm:ViewModel x:Key="viewModel"/>
</Window.Resources>
<Grid
DataContext="{StaticResource viewModel}">
Here is where I am setting the selected item for the grid
<igWPF:XamDataGrid
ActiveDataItem="{Binding SelectedObj1}"
DataSource="{Binding observableCollection}"

If your view doesn’t exist yet when the view model is created, then of course, the view isn’t listening yet when your properties update. However, when the view is then created and the view model is assigned as its data context, then the view will automatically load the values from the view model (its data context).
So, INPC shoulnd’t be an issue there at all. You could create properties without INPC in your example and have it work (since the values are already set in the constructor).

WP7 Binding a checkbox IsChecked to an sql database bit C#

I am trying to bind a checkboxs IsChecked property to a bit value stored in an sql database as Underlay.
The data context for the page is a room object, pulled strait from the db, which contains the stored bit.
newPiv.DataContext = viewModel.db.Rooms.SingleOrDefault(r => r.RoomId == roomNumber);
xaml code
<CheckBox x:Name="underlayCB" IsChecked="{Binding Underlay, Mode=TwoWay, UpdateSourceTrigger=Explicit}" />
database:
private System.Nullable<bool> _Underlay;
partial void OnUnderlayChanging(System.Nullable<bool> value);
partial void OnUnderlayChanged();
[Column(Storage = "_Underlay", DbType = "Bit")]
public System.Nullable<bool> Underlay
{
get
{
return this._Underlay;
}
set
{
if ((this._Underlay != value))
{
this.OnUnderlayChanging(value);
this.SendPropertyChanging();
this._Underlay = value;
this.SendPropertyChanged("Underlay");
this.OnUnderlayChanged();
}
}
}
I have several other bindings on the same page and other pages within the app which all work, could someone tell me what I am missing?

You have set the Binding's UpdateSourceTrigger to Explicit, this requires you to call Binding.UpdateSource() does one the methods your setter calls do that? Why not just leave it as Default or PropertyChanged?
Is INotifyPropertyChanged's event raised?
Incidentally instead of
private System.Nullable<bool> _Underlay;
You can have:
private bool? _Underlay;

Composite Binding to property and inner viewmodel property not firing

I've created a property "IsLoading" for my main view model. The idea is that a progressbar is displayed whenever this property is set to true. So far so good
The catch is, that I have a command, that calls another viewmodel (the code is there because it's a functionality from another page, but I want to be able to shortcut it as well from my main viewmodel)
So, I went ahead and modified the main property to something like this :
public const string IsLoadingPropertyName = "IsLoading";
private bool _isLoading;
public bool IsLoading
{
get
{
return _isLoading || ((ViewModelLocator)Application.Current.Resources["Locator"]).SettingsViewModel.IsLoading;
}
set
{
if (value != _isLoading)
{
_isLoading = value;
RaisePropertyChanged(IsLoadingPropertyName);
}
}
}
and the xaml
<shell:SystemTray.ProgressIndicator>
<shell:ProgressIndicator IsIndeterminate="true" IsVisible="{Binding Main.IsLoading, Source={StaticResource Locator}}" />
</shell:SystemTray.ProgressIndicator>
So, I'm saying that main view model is loading when there's something loading there, or if the settings view model is loading.
The problem is that the binding only works when setting the main view model's IsLoading property, it doesn't react when I set it in the inner IsLoading one. Both have the same property name "IsLoading". Shouldn't it be detected?
For example, in Main view model (just the execution of the command for simplicity) :
private void ExecuteRefreshCommand()
{
ViewModelLocator viewModelLocator = Application.Current.Resources["Locator"] as ViewModelLocator;
viewModelLocator.SettingsViewModel.GetCurrentLocationCommand.Execute(null);
}
and inside the settings view model :
public RelayCommand GetCurrentLocationCommand
{
get
{
Action getLocation = () =>
{
if (!NetworkInterface.GetIsNetworkAvailable())
{
return;
}
var watcher = new GeoCoordinateWatcher(GeoPositionAccuracy.Default);
watcher.PositionChanged += WatcherPositionChanged;
IsLoading = true; // settings view model "IsLoading" propertychanged raising property
watcher.Start();
};
return new RelayCommand(getLocation);
}
}

You're looking at the MainViewModel's isLoading property to determine whether to show the progressbar or not. Silverlight uses the NotifyPropertyChanged event to determine when it should reevaluate a certain property. When setting either the SettingsViewModel's IsLoading property- or the MainViewModel's property, you only raise the changedEvent for that ViewModel. You should raise the ChangedEvent for both.
A modified setter example could be (depending on the exposed methods)
set
{
if (value != _isLoading)
{
_isLoading = value;
RaisePropertyChanged(IsLoadingPropertyName);
((ViewModelLocator)Application.Current.Resources["Locator"]).SettingsViewModel.RaisePropertyChanged(IsLoadingPropertyName);
}
}
Note that many MVVM frameworks offer a functionality called Messaging which is ideal to do cross ViewModel communication without creating the strict dependency you created right now. Alternatively you can use a globally consumed IsLoading property.