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
This Property is in the View Model of the Main Window
xaml
What am I doing Wrong?
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
This Property is in the View Model of the Main Window
Public Property localCurrentUser As CurrentUser = CurrentUser.GetCurrentUser
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>
What am I doing Wrong?
.NET ProgrammingVisual Basic.NET
Last Comment
p-plater
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)
Isn't that what the INotifyPropertyChanged is supposed to do?
(I am implementing the INotifyPropertyChanged in the Base class)
ASKER
It Appears I need to raise a StaticPropertyChanged event.
I can only find C# examples - can you help me convert it to VB?
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));
}
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.
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.
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ASKER
Other Comments didn't solve the Question.
I Experimented until I managed to get it to work
I Experimented until I managed to get it to work
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.