MVVM radiobuttons

Question

Someone please help. I have an interesting issue. I am trying to implement an MVVM app and I want to bind to radiobuttons in my view.

Here's my view:

<StackPanel Orientation="Horizontal" Grid.ColumnSpan="2"  >     <RadioButton GroupName="1" IsChecked="{Binding Path=NoteGeneral, Mode=TwoWay}">General</RadioButton>     <RadioButton GroupName="1" IsChecked="{Binding Path=NoteContact, Mode=TwoWay}" >Contact</RadioButton>     <RadioButton GroupName="1" IsChecked="{Binding Path=NoteAddress, Mode=TwoWay}" >Address</RadioButton>     <RadioButton GroupName="1" IsChecked="{Binding Path=NotePhone, Mode=TwoWay}" >Phone</RadioButton> </StackPanel> 

Here's my ViewModel:

    bool _NoteGeneral;     public bool NoteGeneral     {         get { return _NoteGeneral; }         set         {             _NoteGeneral = value;             OnPropertyChanged("NoteGeneral");         }     }      bool _NoteContact;     public bool NoteContact     {         get { return _NoteContact; }         set         {             _NoteContact = value;             OnPropertyChanged("NoteContact");         }     }      bool _NoteAddress;     public bool NoteAddress     {         get { return _NoteAddress; }         set         {             _NoteAddress = value;             OnPropertyChanged("NoteAddress");         }     }      bool _NotePhone;     public bool NotePhone     {         get { return _NotePhone; }         set         {             _NotePhone = value;             OnPropertyChanged("NotePhone");         }     } 

The problem is this, when I click the different radiobuttons the property setter only gets called the first time(when i run thru debugging). e.g. When I click NoteGeneral, NoteContact, then NoteGeneral again only the first two clicks update my viewmodel. I think I might have something wrong with my binding, or maybe I'm approaching this the completely wrong way.

Can anyone help?

How should I implement radiobutton selections in my viewmodel?

.NET 4 and Later

This issue with RadioButton binding was resolved by Microsoft when .NET 4 was released. Binding of RadioButtons now works as you would expect without any of the work-arounds listed below.

Answer 1

Take a look here.

I haven't implemented the solution provided but it makes sense. The underlying framework control breaks you bindings when a click is performed. The solution is to override the method that does this and just rely on the bindings.

Answer 2

Jaime Rodriguez, who works at Microsoft on WPF, publishes an unabridged Q&A on WPF, and the latest issue has a post on RadioButtons and MVVM !

The post is at http://blogs.msdn.com/jaimer/archive/2009/09/22/wpf-discussion-090922.aspx, and you want to look at the last item in that post. I tested the solution and it works to my satisfaction.

Quoted for convenience:

I've worked around this issue in .NET 3.5 SP1. Here's how I data bind a group of radio buttons to an enum-valued property:

<StackPanel>     <RadioButton Content="New folder"         IsChecked="{Binding Path=PublishTarget,                     Converter={StaticResource equalityConverter},                     ConverterParameter={x:Static local:PublishTarget.NewServerFolder}, Mode=TwoWay}"         GroupName="1" />      <RadioButton Content="Existing folder"         IsChecked="{Binding Path=PublishTarget,                     Converter={StaticResource equalityConverter},                     ConverterParameter={x:Static local:PublishTarget.ExistingServerFolder},                     Mode=TwoWay}"         GroupName="2" />      <RadioButton Content="Local folder"         IsChecked="{Binding Path=PublishTarget,                     Converter={StaticResource equalityConverter},                     ConverterParameter={x:Static local:PublishTarget.LocalFolder},                     Mode=TwoWay}"         GroupName="3" /> </StackPanel> 

Setting each radio button's GroupName to a unique value prevents the bindings from getting clobbered when the user clicks on a radio button. Here I'm relying on the data source to implement INotifyPropertyChanged, which will tell the other radio buttons to update. A similar approach should work for radio buttons in an ItemsControl.