IridiumIO.MVVM.VBSourceGenerators 0.2.0

MVVM.VBSourceGenerators

The CommunityToolkit.MVVM source generators only work in C#. This package augments the toolkit to allow some of the generators to work for VB.NET.

Working

• <ObservableProperty> attribute generates a public property with change notification.
• <NotifyPropertyChangedFor(NameOf(T))> attribute generates a property with change notification for existing properties.
• <RelayCommand>
  • Can decorate Sub, Async Sub, or Async Function
  • Supports CanExecute callback functionality
  • Supports passing a parameter to the command

Planned

• <RelayCommand>
  • Passing cancellation tokens
• NotifyCanExecuteChangedFor(NameOf(T))

Installation

1. Add the NuGet package for MVVM.VBSourceGenerators to your VB.NET project:

   dotnet add package IridiumIO.MVVM.VBSourceGenerators
   

2. Ensure that you also reference CommunityToolkit.MVVM in your project.

ObservableProperty Usage

1. In your VB.NET ViewModel, use the [ObservableProperty] attribute as you would in C#
2. Make sure your fields follow the naming convention of starting with an underscore (e.g., _name).
3. You can then use the generated Uppercase property Name in your code.

Example 1:

Imports CommunityToolkit.Mvvm.ComponentModel

Partial Public Class MyViewModel
    Inherits ObservableObject

    <ObservableProperty>
    Private _name As String
End Class

Example 2: Including NotifyPropertyChangedFor

Imports CommunityToolkit.Mvvm.ComponentModel

Partial Public Class PersonViewModel
    Inherits ObservableObject

    <ObservableProperty>
    <NotifyPropertyChangedFor(NameOf(FullName))>
    Private _firstName As String

    <ObservableProperty>
    <NotifyPropertyChangedFor(NameOf(FullName))>
    Private _lastName As String

    Public ReadOnly Property FullName As String
        Get
            Return $"{FirstName} {LastName}"
        End Get
    End Property

End Class

RelayCommand Usage

1. In your VB.NET ViewModel, use the [RelayCommand] attribute as you would in C# on a method.

Examples:

Imports CommunityToolkit.Mvvm.ComponentModel

Partial Public Class MyViewModel
    Inherits ObservableObject

    <RelayCommand>
    Private Sub Save()
        ' Save logic here
    End Sub

    <RelayCommand>
    Private Sub SelectItem(item As String)
        ' Logic to select an item
    End Sub

    <RelayCommand>
    Private Async Function LoadDataAsync() As Task
        ' Load data logic here
        Await Task.Delay(1000) ' Simulating async work
    End Function

End Class

Example 2: Including CanExecute callback

By creating a function that returns a Boolean and prefixing it with Can, you can control whether the command can execute.

Imports CommunityToolkit.Mvvm.ComponentModel

Partial Public Class PersonViewModel
    Inherits ObservableObject

    <RelayCommand>
    Private Sub SaveData()
        ' Logic to save data
    End Sub

    Private Function CanSaveData() As Boolean
        ' Logic to determine if saving is allowed
         Return MyData.Count > 0
    End Function

End Class