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Ron KiddFlag for Australia

asked on

Data bind to a Shared Property WPF

I have a Class with Shared Properties
This Class holds the Name and ID of the Current User.
It all works fine until I try to databind to the Shared Values.

When I update the Shared Values in Code the Displayed Values stay the same.
But if I update the Displayed Values (In the Text box) the Bound Shared Properties DO update.

Class
Public Class CurrentUser
    Inherits CommonViewModelBase

    Private Shared _name As String = "No Name"
    Private Shared _ID As Integer
    Private Shared _thisInstance As CurrentUser


    Public Shared Property name As String
        Get
            Return _name
        End Get
        Set(value As String)
            _name = value
            _thisInstance.OnPropertyChanged(NameOf(name))
        End Set
    End Property

    Public Shared Property ID As Integer
        Get
            Return _ID
        End Get
        Set(value As Integer)
            _ID = value
            _thisInstance.OnPropertyChanged(NameOf(ID))
        End Set
    End Property

    Protected Sub New()
        'initialization code goes here

    End Sub

    Public Shared Function GetCurrentUser() As CurrentUser
        '
        ' initialize object if it hasn't already been done
        '
        If _thisInstance Is Nothing Then
            _thisInstance = New CurrentUser
        End If
        '
        ' return the initialized instance
        '
        Return _thisInstance
    End Function

End Class

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This Property is in the View Model of the Main Window
Public Property localCurrentUser As CurrentUser = CurrentUser.GetCurrentUser

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xaml
<StackPanel Orientation="Horizontal" Grid.Row="4" HorizontalAlignment="Right" DataContext="{Binding localCurrentUser}">
            <TextBlock Name="StaffNameTextBlock1" Text="Staff Name (Click to Change) "/>
            <TextBlock x:Name="StaffNameTextBlock" Text="{Binding name, Mode=TwoWay, ValidatesOnDataErrors=True, ValidatesOnExceptions=True}"/>
        </StackPanel>

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What am I doing Wrong?
Avatar of AndyAinscow
AndyAinscow
Flag of Switzerland image

>>When I update the Shared Values in Code the Displayed Values stay the same.

Typically the interface will only update when it is changed or instructed to do so from code.  So your behavior is what I would expect.  When you want to modify the values from code you need to force the UI to update or you modify the values in the UI directly.
Avatar of Ron Kidd

ASKER

So how do I tell the UI to update?

Isn't that what the INotifyPropertyChanged is supposed to do?
(I am implementing the INotifyPropertyChanged in the Base class)
It Appears I need to raise a StaticPropertyChanged event.
I can only find C# examples - can you help me convert it to VB?

public static event EventHandler<PropertyChangedEventArgs> StaticPropertyChanged;
public static void RaiseStaticPropertyChanged(string propName)
{
    EventHandler<PropertyChangedEventArgs> handler = StaticPropertyChanged;
    if (handler != null)
        handler(null, new PropertyChangedEventArgs(propName));
}

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https://msdn.microsoft.com/library/ms743695%28v=vs.100%29.aspx
The above microsoft site gives both a C# and the equivalent VB code.  It looks to be pretty much what you have the C# code in your example.
ASKER CERTIFIED SOLUTION
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Ron Kidd
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Other Comments didn't solve the Question.
I Experimented until I managed to get it to work