How to bind DependencyProperty without using MVVM

Question

Well, I am doing a small project and I found it wasn't necessary to implemente a full MVVM.

I am trying to bind some properties in code behind, but cannot manage to make it works.

The point is the use of DependencyProperties and Binding in code behind.

I tried to follow these links and questions in SO:

Bind Dependency Property in codebehind WPF

How to: Create a Binding in Code

Bind Dependency Property, defined in Code-Behind, through Xaml to a Property in the DataContext of a UserControl

But they are related to MVVM or at least I cannot adapt the code in my case.

The example should be very simple.

MainWindow.xaml

<Label Name="_lblCurrentPath" Style="{StaticResource CustomPathLabel}" ToolTip="{Binding CurrentPath}" Content="{Binding CurrentPath, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>

MainWindow.xaml.cs

public MainWindow() { InitializeComponent(); SetBindings(); } #region Properties public static readonly DependencyProperty CurrentPathProperty = DependencyProperty.Register("CurrentPath", typeof(String), typeof(MainWindow), new PropertyMetadata(String.Empty, OnCurrentPathChanged)); public string CurrentPath { get { return (String)GetValue(CurrentPathProperty); } set { SetValue(CurrentPathProperty, value); } } #endregion #region Bindings private void SetBindings() { // Label CurrentPath binding Binding _currentPath = new Binding("CurrentPath"); _currentPath.Source = CurrentPath; this._lblCurrentPath.SetBinding(Label.ContentProperty, _currentPath); } #endregion #region Methods private void Refresh() { MessageBox.Show("Refresh!"); } private string Search() { WinForms.FolderBrowserDialog dialog = new WinForms.FolderBrowserDialog(); WinForms.DialogResult _dResult = dialog.ShowDialog(); switch(_dResult) { case WinForms.DialogResult.OK: CurrentPath = dialog.SelectedPath; break; default: break; } return CurrentPath; } #endregion #region Events private static void OnCurrentPathChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { MainWindow instance = d as MainWindow; instance.Refresh(); } public void OpenSearchEclipsePath(object sender, RoutedEventArgs e) { CurrentPath = Search(); } public void RefreshEclipsePath(object sender, RoutedEventArgs e) { Refresh(); }

Any idea?

.If this is a bad practice and I should use MVVM comments are welcome, of ourse.

.Also... Related to Command property. In this case where I don't want to use a MVVM approach, is it better to register events? I found the use of custom command bindings a little bit tedious.

Its bad practice, you should use MVVM (you said we could comment ;) ). — BradleyDotNET
– BradleyDotNET, Commented Nov 4, 2014 at 19:20

BradleyDotNET · Accepted Answer · 2014-11-04 19:10:50Z

First, you can totally use bindings without MVVM. I wouldn't reccommend it, as the code is a lot cleaner when you use MVVM, but it can be done. All you need to do is put this line in your constructor:

this.DataContext = this;

Now your view is also your view model! Like I said, not a good idea.

Now, the code you have has a DependencyProperty in your MainWindow class. Don't do that. It serves absolutely no purpose. DPs are there so parent controls can give a binding to them. MainWindow has no parent; so a DP is useless.

All you need to do is set up a regular property:

public string CurrentPath { get { return currentPath; } set { currentPath = value; NotifyPropertyChanged(); } }

And then have MainWindow implement INotifyPropertyChanged (did I mention that it makes more sense to use a simple view model?).

To answer your Command question. Yes, if you are opposed to using commands, just register for the events. However, Command is a really nice way to get user clicks into the view model without breaking MVVM. The syntax isn't that bad. If you are going the "View as a View Model" approach anyways though, Command doesn't buy you much.

Thanks. It was easy. Yes, in the end I think I will use a MVVM approach. I used to create them custom, but I found very nice frameworks like mvvmlight or caliburn
@blacai Go right ahead and use your favorite framework, but it takes me all of five minutes to set up my own for each new project I do. It really isn't that hard. Glad to hear you are going to do it the right way though!
Well, at the moment I don't have favorite framework. Like I said I use to create my own but I see a lot of questions about them and would be nice to take a look :)
@blacai Meh, 98% of the time frameworks make my life harder, so I try and avoid them unless I really need them. Good luck in your search though.

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