Subclassed Properties Not Binding

RogerSchlueter-7899 1,196 Reputation points
2023-01-30T00:34:53.67+00:00

In my ViewModel I have this subclass:

Public Class Printing
    Public AccountName As Boolean
    Public AccountNumber As Boolean
    Public Expiration As Boolean
    Public SecurityCode As Boolean
End Class

which I use as follows:

Private _PrintList As New Printing
Public Property PrintList As Printing

This is referred to in the View as follows:

<CheckBox IsChecked="{Binding Path=PrintList.AccountName}" />

This gives a run-time error:

BindingExpression path error: 'AccountName' property not found on 'object' ''Printing

I do not understand why this binding fails.

Windows Presentation Foundation
Windows Presentation Foundation
A part of the .NET Framework that provides a unified programming model for building line-of-business desktop applications on Windows.
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VB
VB
An object-oriented programming language developed by Microsoft that is implemented on the .NET Framework. Previously known as Visual Basic .NET.
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Accepted answer
  1. Reza Aghaei 4,936 Reputation points MVP
    2023-01-30T00:40:33.7133333+00:00

    Databinding require property. You forgot to use Property keyword, and you have defined fields. You need to use Property keyword when defining properties; For example:

    Public Class Printing
    Public Property AccountName As Boolean
    Public Property AccountNumber As Boolean
    Public Property Expiration As Boolean
    Public Property SecurityCode As Boolean
End Class

    For more information:

1 additional answer

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  1. Hui Liu-MSFT 38,191 Reputation points Microsoft Vendor
    2023-01-30T02:58:50.5633333+00:00

    As Reza Aghaei said, Databinding require property. You could refer to the following example.

     <Window.DataContext>
        <local:ViewModel />
    </Window.DataContext>
    <StackPanel>
        <CheckBox IsChecked="{Binding Path=PrintList.AccountName}" />
        <TextBox Text="{Binding PrintList.AccountName ,UpdateSourceTrigger=PropertyChanged ,Mode=TwoWay }"/>
    </StackPanel>

    Imports System.Collections.ObjectModel
Imports System.ComponentModel
Imports System.Windows.Automation

Class MainWindow

End Class
Public Class ViewModel

    Public Property PrintList() As Printing = New Printing()

    Public Sub New()
        PrintList.AccountName = True
    End Sub

    Public Class Printing
        Implements INotifyPropertyChanged

        Private _AccountName As Boolean = False
        Public Property AccountName As Boolean
            Get
                Return Me._AccountName
            End Get

            Set(ByVal value As Boolean)
                Me._AccountName = value
                NotifyPropertyChanged("AccountName")
            End Set
        End Property
        Public Property AccountNumber As Boolean
        Public Property Expiration As Boolean
        Public Property SecurityCode As Boolean


        Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
        Private Sub NotifyPropertyChanged(ByVal propertyName As String)
            RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
        End Sub
    End Class


End Class

    The result:

    22

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