WPF Data Binding to changing object?

Most UI bindings already handle this via property notifications, in particular (for WPF) INotifyPropertyChanged . - i.e. If you are updating the UserId on a single instance.

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I have a user control which displays the currently logged in user's name. I have bound a TextBlock in the control to the UserId property of a User obejct in my application. The issue I have is that the User object my binding has as a source changes each time a new user logs in.

I can think of a solution where I fire an event when the User obejct changes and this is caught my by control which then reinitialise's the binding but this seems less than ideal. Are there a solution to this issue, I feel it must be very common? Cheers, James c# wpf data-binding binding link|improve this question edited May 8 '09 at 10:16RichieHindle49.2k5103184 asked May 8 '09 at 10:10James65521133 78% accept rate.

May 8 '09 at 10:16 If the DataSource is changing, Setting the DataSource to the new object should automatically update bound controls. If a bound property is changing.. you need INotifyPropertyChanged – Gishu May 8 '09 at 12:30.

Most UI bindings already handle this via property notifications, in particular (for WPF) INotifyPropertyChanged. - i.e. If you are updating the UserId on a single instance: class User : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; protected virtual void OnPropertyChanged(string propertyName) { PropertyChangedEventHandler handler = PropertyChanged; if(handler!

=null) handler(this, new PropertyChangdEventArgs( propertyName)); } private string userId; public string UserId { get {return userId;} set { if(userId! = value) { userId = value; OnPropertyChanged("UserId"); } } } } This should then update the binding automatically. If you are, instead, changing the actual user instance, then consider the same trick, but against whatever hosts the user: public User User { get {return user;} set { if(user!

= value) { user = value; OnPropertyChanged("User"); } } } And if you are binding to something's "User. UserId", then it should work.

As this will bubble up the changes. To your bound controls.

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