How to raise event when Current application property is changed.

Question

I have a WPF application.

In my App.xaml.cs I save the full name of the logged in user as follows:

App.Current.Properties["FullName"] = GetValueFromDatabase();

I have two screens/windows in the same application.

First is the users scrren, which has a an editable WPF data grid where I can update full name of the current user. Second is a screen which has a Label/TextBox control which displays the Current users fullname from the Application object.

When both the windows are open, if I change the full name of the user and save the changes in the first screen. I want to trigger an event so that, it is also reflected in the second screen immediately?

Which event do I hook to this application and how?

I am using MVVM pattern and entity framework.

Answer 1

You should use a dependency property or make sure your model is an INotifyPropertyChanged so that others can bind to it in either the screen or window using a {Binding}

// if your model is derived from a sub-class of DependencyObject....
class Model : DependencyObject 
{
    public static readonly DependencyProperty MyStringProperty = 
      DependencyProperty.Register("MyString", typeof(string), 
      typeof(IncidentGraphic), new UIPropertyMetadata(string.Empty));

    public string MyString
    {
     get { return (string)GetValue(MyStringProperty ); }
     set { SetValue(MyStringProperty , value); }
    }
}

/// recommended to use INotifyPropertyChanged
class Model : INotifyPropertyChanged
{
     private void NotifyChange(string property)
     {
       PropertyChangedEventHandler handler = this.PropertyChanged;
       if (handler != null)
       {
         handler(this, new PropertyChangedEventArgs(property));
       }
     }

     string m_MyString = string.Empty;
     public string MyString
     {
       get
       {
         return m_MyString ;
       }
       set
       {
         if ( value != this.m_MyString )
         {
           this. m_MyString  = value;
           NotifyChange("MyString");
         }
             }
     }
}

// in your xaml.....
    <TextBox Text="{Binding MyString}" />

Answer 2

I have implemented a Mediator class, which acts as a medium to communicate between the ViewModels of both the Windows.

I referred this article : http://sachabarber.net/?p=477