ObservableProperty - IridiumIO/MVVM.VBSourceGenerators GitHub Wiki

Used to generate a Property for the given private field that makes use of the MVVM Toolkit's ObservableObject PropertyChanged notifications.

This generated property will include several supporting Partial methods that can be implemented if chosen. If you do not use these methods, the compiler will strip them out avoiding any runtime overhead.

Microsoft Docs

[!IMPORTANT] Compared to CSharp, the field in VB.NET must be prefixed with an underscore ("_") or it will not work.

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Supported on

• Fields
• Properties (VB.NET does not support partial properties)
• Classes

Requires

• Class must be partial
• Class must inherit from ObservableObject or ObservableRecipient
• Class-level <ObservableObject> attribute is not supported yet

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Usage

Given the annotated field like so:

Public Partial Class MyViewModel : Inherits ObservableObject

    <ObservableProperty>
    Private _firstName As String

End Class

The following code will be generated:

Public Property FirstName As String
    Get
        Return _firstName
    End Get
    Set(value As String)
        If Global.System.Collections.Generic.EqualityComparer(Of String).Default.Equals(_firstName, value) Then Return
        OnFirstNameChanging(value)
        OnFirstNameChanging(Nothing, value)
        OnPropertyChanging(NameOf(FirstName))
        _firstName = value
        OnFirstNameChanged(value)
        OnFirstNameChanged(Nothing, value)
        OnPropertyChanged(NameOf(FirstName))
        OnPropertyChanged(NameOf(FullName))
    End Set
End Property

Partial Private Sub OnFirstNameChanging(value As String): End Sub
Partial Private Sub OnFirstNameChanging(oldValue As String, newValue As String): End Sub
Partial Private Sub OnFirstNameChanged(value As String): End Sub
Partial Private Sub OnFirstNameChanged(oldValue As String, newValue As String): End Sub