Push Shared Property value change to object instances Vb.Net

Question

Hallo All,

I have following code and i am trying to push the shared property change to another class object instances. I have a class setting with shared property language.

I have another class Test where it takes this shared property. I want to change the language property in setting so that the change of language immediately updated in my Test object instances. How do i do it?.

Thanks

Imports System.ComponentModel  
Imports System.Runtime.CompilerServices  
  
Public Class Form1  
  
    Public Test As New Tests  
    Public BS_Setting As New BindingSource  
  
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load  
        BS_Setting.DataSource = Test  
        DataGridView2.DataSource = BS_Setting  
    End Sub  
    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click  
        BS_Setting.Add(New Test())  
    End Sub  
    Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click  
        Setting.language = "French"  
    End Sub  
  
End Class  
  
  
Public Class Setting  
    Implements INotifyPropertyChanged  
  
    Public Sub New()  
    End Sub  
  
    Public Shared languageValue As String = "ENG"  
    Public Shared Property language() As String  
        Get  
            Return languageValue  
        End Get  
        Set(ByVal value As String)  
            languageValue = value  
        End Set  
    End Property  
  
    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged  
    Protected Overridable Sub OnPropertyChanged(<CallerMemberName> Optional memberName As String = Nothing)  
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(memberName))  
    End Sub  
End Class  
  
Public Class Test  
    Public Sub New()  
    End Sub  
  
    Private LangValue As String  
    Public Property Lang As String  
        Get  
            Return Setting.language  
        End Get  
        Set(ByVal value As String)  
            LangValue = value  
        End Set  
    End Property  
  
End Class  
  
Public Class Tests  
    Inherits BindingList(Of Test)  
End Class  
  

Answer 1

Hi @Hobbyist_programmer ,

I want to change the language property in setting so that the change of language immediately updated in my Test object instances.

Try to refresh the DataGridView when you change the 'language' property.

        Setting.language = "French"  
        DataGridView2.Refresh()  

Result of my test.

Hope it could be helpful.

Best Regards,
Xingyu Zhao
*
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Answer 2

wow.. thanks for the answer XingyuZhao.

Answer 3

Why shared properties are not showing up in the datagridview?

Answer 4

Hello @Hobbyist_programmer

Even though you have an accepted solution I'd like to provide another solution.

• Rather than a shared field use a non-shared field unless you want all existing rows to change.
• There is really no need to have a wrapper class simply for the BindingList, instead use the Setting class assigned to a BindingSource in the form. The class should really only have properties and INotifyPropertyChanged event and OnPropertyChanged

Setting class
Read the comments

Imports System.ComponentModel  
Imports System.Runtime.CompilerServices  
  
Namespace Classes  
    Public Class Setting  
        Implements INotifyPropertyChanged  
  
        Public Sub New(Optional language As String = "English")  
            languageValue = language  
        End Sub  
        ''' <summary>  
        ''' Shared modifier means all instances are affected,  
        ''' remove Shared if that is not what you want.  
        ''' </summary>  
        Public languageValue As String = ""  
        Public Property Language() As String  
            Get  
                Return languageValue  
            End Get  
            Set  
                languageValue = Value  
                '  
                ' Make sure to implement the line below  
                '  
                OnPropertyChanged()  
            End Set  
        End Property  
  
        Public Event PropertyChanged As PropertyChangedEventHandler _  
            Implements INotifyPropertyChanged.PropertyChanged  
  
        Protected Overridable Sub OnPropertyChanged(  
            <CallerMemberName> Optional memberName As String = Nothing)  
            RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(memberName))  
  
        End Sub  
    End Class  
End Namespace  

Form code

Imports System.ComponentModel  
Imports BindingWithoutRefreshing.Classes  
  
Public Class Form1  
  
    Public SettingsBindingSource As New BindingSource  
    Public SettingsBindingList As New BindingList(Of Setting)  
  
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load  
        DataGridView2.AutoGenerateColumns = False  
  
        SettingsBindingList = New BindingList(Of Setting)(New List(Of Setting))  
        SettingsBindingSource.DataSource = New BindingSource(SettingsBindingList, Nothing)  
  
        DataGridView2.DataSource = SettingsBindingSource  
  
        LanguagesComboBox.DataSource = New List(Of String) From {"English", "French", "Spanish"}  
  
    End Sub  
  
    Private Sub AddNewSettingButton_Click(sender As Object, e As EventArgs) _  
        Handles AddNewSettingButton.Click  
  
        SettingsBindingSource.Add(New Setting(LanguagesComboBox.Text))  
        SettingsBindingSource.MoveLast()  
  
    End Sub  
  
    Private Sub ChangeLanguageButton_Click(sender As Object, e As EventArgs) _  
        Handles ChangeLanguageButton.Click  
  
        If SettingsBindingSource.Current IsNot Nothing Then  
            CType(SettingsBindingSource.Current, Setting).Language = LanguagesComboBox.Text  
        End If  
  
    End Sub  
  
    Private Sub DataGridView2_DefaultValuesNeeded(sender As Object, e As DataGridViewRowEventArgs) _  
        Handles DataGridView2.DefaultValuesNeeded  
  
        e.Row.Cells(0).Value = LanguagesComboBox.Text  
  
    End Sub  
End Class  

Full source GitHub repository