Question

I have created a wpf vb.net project and am trying to set a simple databing. I’m not quiet sure how to set my DataContext = this; in the codebind. Currently when i run the program my Label never is updated. I have included my code below. What I’m i missing?

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Label Content="{Binding person.Name}"/>
    </Grid>
</Window>

Class MainWindow 
    Private Property person As New Person()

    Public Sub New()

        ' This call is required by the designer.
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.
        person.Name = "Poco"
    End Sub
End Class

System.ComponentModel

Public Class Person
    Implements INotifyPropertyChanged

    Private _name As String
    Public Property Name() As String
        Get
            Return _name
        End Get
        Set(ByVal value As String)
            _name = value

            OnPropertyChanged(New PropertyChangedEventArgs("Name"))
        End Set
    End Property

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged

    Public Sub OnPropertyChanged(ByVal e As PropertyChangedEventArgs)
        If Not PropertyChangedEvent Is Nothing Then
            RaiseEvent PropertyChanged(Me, e)
        End If
    End Sub
End Class

Answer 1

This is close – you need to name your label in the XAML (so that you can reference it from the code behind) and then specify the path within the bound object to the data you would like to bind. In this case you will be binding an object with a Name property whose content you would like to assign to the label text:

<Label Name="MyLabel" Content="{Binding Path = Name}"/>

and then in your code you need to set the DataContext of the label to the object you would like to have it bound to, in this case a specific instance, somePerson of the class Person :

Private somePerson As New Person

Public Sub New()
    InitializeComponent()
    MyLabel.DataContext = somePerson
    somePerson.Name = "Poco"
End Sub