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Databinding to an Object property fails, to the parent it is working

I tried to bind a property to a nested object, but it fails.
I have taken a look at those questions, but i think i made another mistake somewhere else. Maybe someone can give i hind.
WPF: How to bind to a nested property?
binding to a property of an object
To upper slider/textbox has a correct binding while the lower one fails to do so.
I have two sliders with corrosponding textboxes:
<StackPanel>
<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
<TextBox Text="{Binding Path= boundnumber, Mode=TwoWay, FallbackValue='binding failed'}" ></TextBox>
<Slider Value="{Binding Path= boundnumber, Mode=TwoWay}" Width="500" Maximum="1000" ></Slider>
</StackPanel>
<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center" DataContext="{Binding Path=myDatarow}">
<TextBox Text="{Binding Path= boundnumber, Mode=TwoWay, FallbackValue='binding failed'}" ></TextBox>
<Slider Value="{Binding Path= boundnumber, Mode=TwoWay}" Width="500" Maximum="1000" ></Slider>
</StackPanel>
</StackPanel>
Code behind:
public partial class MainWindow : INotifyPropertyChanged
{
public MainWindow()
{
DataContext = this;
InitializeComponent();
}
private int _boundnumber;
public int boundnumber
{
get { return _boundnumber; }
set
{
if (value != _boundnumber)
{
_boundnumber = value;
OnPropertyChanged();
}
}
}
Datarow myDatarow = new Datarow(11);
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged([CallerMemberName] string propertyname = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyname));
}
}
class Datarow : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged([CallerMemberName] string propertyname = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyname));
}
public Datarow()
{
}
public Datarow(int number)
{
boundnumber = number;
}
private int _boundnumber;
public int boundnumber
{
get { return _boundnumber; }
set
{
if (value != _boundnumber)
{
_boundnumber = value;
OnPropertyChanged();
}
}
}
}

You need to expose your myDatarow into a public property like your boundnumber.
private DataRow _myDatarow = new DataRow(11);
public DataRow myDataRow
{
get { return _myDatarow; }
}
And just an additional advice.
It's better to separate your DataContext class from the MainWindow.

Data Binding does not Update on Property Change (UWP)

I am developing an application using c# and the Universal Windows Platform (UWP) and am struggling with creating a one-way data-bind between a layout control and an observable class. Currently, when the observable class property is changed, it does not update the UI element. I think it has something to do with the fact that I am binding a DataTemplate ListViewItem rather than a static layout element, but I am not sure if this is the problem or how to solve it. Any help would be appreciated. The code for the UI element and backend code is shown.
DataTemplate (XAML) (Styling is removed for readability)
<DataTemplate x:Key="variableTemplate"
x:DataType="local:VariableNode">
<Border>
<StackPanel Orientation="Vertical">
<Border>
<Grid>
<TextBlock Text="{Binding Name}" />
<StackPanel Orientation="Horizontal" >
<Button Tag="{Binding Description}"/>
<Button Tag="{Binding}"/>
</StackPanel>
</Grid>
</Border>
<Grid Margin="0, 10">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*"/>
<ColumnDefinition Width="1*"/>
</Grid.ColumnDefinitions>
<Border >
<Grid Grid.Column="0">
<Button Click="Choose_Measurement"
Tag="{Binding}">
<StackPanel Orientation="Vertical">
<TextBlock Text="{x:Bind Path=Measurement_Name, Mode=TwoWay}"
Foreground="{x:Bind MF}" />
<TextBlock Foreground="{x:Bind MF}" />
</StackPanel>
</Button>
</Grid>
</Border>
<Grid Grid.Column="1">
<Button Foreground="{Binding UF}"
Tag="{Binding}"
IsEnabled="{Binding Unit_Exists}"
Click="Choose_Unit">
<StackPanel Orientation="Vertical">
<TextBlock Text="{x:Bind Path=Unit_Name, Mode=OneWay}"
Foreground="{Binding UF}" />
<TextBlock Foreground="{Binding UF}" />
</StackPanel>
</Button>
</Grid>
</Grid>
</StackPanel>
</Border>
</DataTemplate>
C# Observable Class VariableNode (Irrelevant properties removed)
public class VariableNode : ExperimentNode
{
public VariableNode() { }
public VariableNode(VariableType type)
{
Type = type;
Name = name_ref[(int)Type];
Category = "Problem";
Unit = -1;
}
private string[] name_ref = { "Independent Variable", "Dependent Variable", "Controlled Variable" };
public enum VariableType { Independent, Dependent, Controlled };
public VariableType Type { get; set; }
public Measurement Measure { get; set; }
public int Unit { get; set; }
[XmlIgnoreAttribute]
public Measurement MeasureSource
{
get { return this.Measure; }
set
{
this.Measure = value;
OnPropertyChanged("Measurement_Name");
}
}
[XmlIgnoreAttribute]
public string Measurement_Name
{
get
{
if (Measure == null) { return "Select a Measurement"; }
else { return Measure.Name; }
}
set
{
if (Measure != null)
{
Measure.Name = value;
OnPropertyChanged();
}
}
}
[XmlIgnoreAttribute]
public string Unit_Name
{
get
{
if (Measure == null) { return "No measurement"; }
else if (Unit < 0) { return "Select a unit"; }
else { return Measure.Unit[Unit]; }
}
}
[XmlIgnoreAttribute]
public bool Unit_Exists
{
get { return Measure != null; }
}
}
C# XAML.CS code calling the property change
public void Choose_Measurement (object sender, RoutedEventArgs e)
{
Button butt = sender as Button
VariableNode sel = butt.Tag as VariableNode;
sel.Measurement_Name = "New Name";
}
Again thanks for the help, I know its a lot of code, and I appreciate the help in debugging / learning.

Ok, so I ended up finding the answer, and I think that it may help others trying to replicate what I am trying to do:
Basically, the class that one is trying to make observable must extend the class INotifyPropertyChanged. So, I ended up making a base class from which to extend all of my observable classes from:
public class BaseClass : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged = delegate { };
protected void OnPropertyChanged(PropertyChangedEventArgs e)
{
PropertyChanged(this, e);
}
protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
OnPropertyChanged(new PropertyChangedEventArgs(propertyName));
}
}

ComboBox Selected Item not updating

Problem
I am trying to bind a ComboBox's SelectedItem to a custom class but this does not update when the property is changed.INotifyPropertyChanged is implemented.
The DataContext
The DataContext is a custom class which contains many properties, but an extract of this is below. You can see it implements INotifyPropertyChanged and this called when the two properties are changed.
public class BctsChange : INotifyPropertyChanged
{
#region declarations
private byContact _Engineer;
public byContact Engineer
{
get { return _Engineer; }
set
{
_Engineer = value;
NotifyPropertyChanged("Engineer");
OnEngineerChanged();
}
}
private BctsSvc.DOSets _LeadingSet;
public BctsSvc.DOSets LeadingSet
{
get { return _LeadingSet; }
set { _LeadingSet = value; NotifyPropertyChanged("LeadingSet"); }
}
#endregion
#region INotify
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(String propertyName = "")
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion
public BctsChange()
{
Engineer = new byContact(Environment.UserName);
}
private void OnEngineerChanged()
{
if (Engineer != null)
{
BctsSvc.DOSets leadSet = GetLeadingSetFromDeptCode(Engineer.DeptCode);
if (leadSet == null) return;
LeadingSet = leadSet;
}
}
private static BctsSvc.DOSets GetLeadingSetFromDeptCode(string DeptCode)
{
BctsSvc.BctsServiceSoapClient svc = new BctsSvc.BctsServiceSoapClient();
BctsSvc.DOSets setX = svc.GetSetFromDeptCode(DeptCode);
return setX;
}
}
The Window XAML
I have several controls on the window, but to keep the code simple I believe the following extract will suffice.
<Window x:Class="MyNamespace.wdSubmit"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:my="clr-namespace:MyNamespace"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
x:Name="ucReqForm"
Title="wdSubmit" >
<StackPanel Orientation="Vertical" HorizontalAlignment="Stretch">
<GroupBox Header="Engineer Details" Name="grpOwnerDetails" >
<StackPanel Orientation="Vertical">
<Grid VerticalAlignment="Top">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="35"/>
</Grid.ColumnDefinitions>
<Label Content="{Binding Engineer.FullName, FallbackValue='Please select an engineer by clicking →', Mode=OneWay}" Margin="5,0" IsEnabled="True" FontStyle="Italic" />
<Button Content="{StaticResource icoSearch}" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Grid.Column="1" Height="23" Name="btnSelectEngineer" Margin="0,0,5,0" HorizontalAlignment="Stretch" ToolTip="Search for an engineer responsible" Click="btnSelectEngineer_Click" />
</Grid>
<ComboBox Height="23" x:Name="ddSet2" Margin="5,0" ItemsSource="{Binding LeadingSets, Mode=OneWay, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}}" SelectedItem="{Binding LeadingSet, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged,NotifyOnTargetUpdated=True}" >
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding SetName}" ToolTip="{Binding HelpInfo}"/>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
<my:LabelledDropdown Height="23" x:Name="ddSet" Margin="5,0" ItemsSource="{Binding LeadingSets, Mode=OneWay, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}}" SelectedItem="{Binding LeadingSet, Mode=TwoWay,NotifyOnTargetUpdated=True,NotifyOnSourceUpdated=True}" Label="e.g. BodyHardware">
<my:LabelledDropdown.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding SetName}" ToolTip="{Binding HelpInfo}"/>
</DataTemplate>
</my:LabelledDropdown.ItemTemplate>
</my:LabelledDropdown>
</StackPanel>
</GroupBox>
</StackPanel>
</Window>
The above extract contains:
A Label that contains a contact's name, and a button to search for a contact, bound to the FullName of the Engineer
A ComboBox that contains departments within the company, bound to an ObservableCollection<DOSets>, which contains a list of departments
Two ComboBoxes, one which is a custom one and the other which is temporary to ensure the bug is not within the control. These are Databound to LeadingSet
Window Code Behind
In the code behind I set the DataContext to CurrentChange. When the user wants to select a different Engineer then this will update the selected department for the engineer in CurrentChange.
When the user changes the engineer, the data binding for the engineer is updated, but the selected department (Leading Set) isn't.
//Usings here
namespace MyNamespace
{
public partial class wdSubmit : Window, INotifyPropertyChanged
{
private BctsSvc.BctsServiceSoapClient svc;
private BctsChange _CurrentChange;
public BctsChange CurrentChange
{
get { return _CurrentChange; }
set { _CurrentChange = value; OnPropertyChanged("CurrentChange"); }
}
private List<BctsSvc.DOSets> _LeadingSets;
public List<BctsSvc.DOSets> LeadingSets
{
get
{
return _LeadingSets;
}
}
public wdSubmit()
{
InitializeComponent();
svc = new BctsSvc.BctsServiceSoapClient();
_LeadingSets = svc.GetLeadSets().ToList();
OnPropertyChanged("LeadingSets");
this._CurrentChange = new BctsChange();
this.DataContext = CurrentChange;
CurrentChange.PropertyChanged += new PropertyChangedEventHandler(CurrentChange_PropertyChanged);
}
void CurrentChange_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
OnPropertyChanged("CurrentChange");
OnPropertyChanged(e.PropertyName);
}
private void btnSelectEngineer_Click(object sender, RoutedEventArgs e)
{
byContact newContact = new frmSearchEngineer().ShowSearch();
if (newContact != null)
{
CurrentChange.Engineer = newContact;
PropertyChanged(CurrentChange, new PropertyChangedEventArgs("LeadingSet"));
PropertyChanged(CurrentChange.LeadingSet, new PropertyChangedEventArgs("LeadingSet"));
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(CurrentChange, new PropertyChangedEventArgs(propertyName));
}
}
}

I've realised the problem may be due to the LeadingSet, returned when the engineer is changed, being a different instance to that in the ObservableCollection.

DataTemplate is not generating ListItemBox

I want to generate ListItemBox using DataTemplate but items are not generating. Please guide me where is the mistake. I have following code in MainWindow.xaml.
<Window x:Class="Offline_Website_Downloader.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:bd="clr-namespace:Offline_Website_Downloader"
Title="Offline Website Downloader" Background="#f5f6f7" Height="500" Width="800"
WindowStartupLocation="CenterScreen">
<Window.Resources>
<bd:BindingController x:Key="BindingControllerKey" />
<DataTemplate x:Key="DownloadedWebsitesListBox">
<StackPanel Orientation="Vertical">
<StackPanel Orientation="Horizontal" Width="Auto">
<TextBlock FontWeight="Bold" FontSize="18" Width="480">
<Hyperlink NavigateUri="http://google.com">
<Label Content="{Binding Path=WebsiteTitle}" />
</Hyperlink>
</TextBlock>
<TextBlock Width="132" TextAlignment="right">
<TextBlock Text="Remaining Time: "/>
<TextBlock Name="TimeRemaining" Text="js"/>
</TextBlock>
</StackPanel>
<StackPanel Orientation="Horizontal">
<ProgressBar Name="progress1" Maximum="100" Minimum="0" Value="30" Background="#FFF" Width="612" Height="10" />
</StackPanel>
<StackPanel Orientation="Horizontal">
<TextBlock HorizontalAlignment="Left" Width="450">Status: <TextBlock Text="{Binding Path=Status}"/></TextBlock>
<TextBlock Width="162" TextAlignment="right">
<TextBlock Text="Downloading Speed: "/>
<TextBlock Name="DownloadingSpeed" Text="{Binding Path=DownloadingSpeed}"/>
</TextBlock>
</StackPanel>
</StackPanel>
</DataTemplate>
</Window.Resources>
<Grid>
<ListBox Width="Auto"
Name="WebsiteList"
Grid.Column="1"
Grid.Row="2"
Grid.RowSpan="2"
ItemsSource="{Binding}"
ItemTemplate="{StaticResource DownloadedWebsitesListBox}"
Margin="0,0,0,0">
</ListBox>
</Grid>
</window>
and MainWindow.xaml.cs
BindingController bc = new BindingController();
public MainWindow()
{
InitializeComponent();
bc.DownloadingSpeed = "40kb/s";
bc.WebsiteTitle = "WebsiteTitle";
bc.Status = "Downloading";
DataContext = bc;
}
and BindingController.cs
public class BindingController
{
public BindingController()
{
}
private string _WebsiteTitle;
public string WebsiteTitle
{
set { _WebsiteTitle = value; }
get { return _WebsiteTitle; }
}
private string _Status;
public string Status
{
set { _Status = value ; }
get { return _Status ; }
}
private string _DownloadStartDate;
public string DownloadStartDate
{
set { _DownloadStartDate = value; }
get { return _DownloadStartDate ; }
}
private string _DownloadingSpeed = "0 kb/s";
public string DownloadingSpeed
{
set { _DownloadingSpeed = value; }
get { return _DownloadingSpeed; }
}
}

Your problem is that you're binding a ListBox to an object that contains several properties, but really only represents a single object/state. The ListBox expects to display a list of items (i.e. IList, IBindingList, IEnumerable, ObservableCollection).
Assuming you want to display more than one download at a time, which I'm assuming given that you're using a ListBox, I would refactor the download properties into a separate class. You will also need to implement INotifyPropertyChanged on your properties so that when the values are changed, they will be shown in the UI.
public class Download : INotifyPropertyChanged
{
private string _WebsiteTitle;
public string WebsiteTitle
{
get { return _WebsiteTitle; }
set
{
if (_WebsiteTitle == value)
return;
_WebsiteTitle = value;
this.OnPropertyChanged("WebsiteTitle");
}
}
private string _Status;
public string Status
{
get { return _Status; }
set
{
if (_Status == value)
return;
_Status = value;
this.OnPropertyChanged("Status");
}
}
private string _DownloadStartDate;
public string DownloadStartDate
{
get { return _DownloadStartDate; }
set
{
if (_DownloadStartDate == value)
return;
_DownloadStartDate = value;
this.OnPropertyChanged("DownloadStartDate");
}
}
private string _DownloadingSpeed = "0 kb/s";
public string DownloadingSpeed
{
get { return _DownloadingSpeed; }
set
{
if (_DownloadingSpeed == value)
return;
_DownloadingSpeed = value;
this.OnPropertyChanged("DownloadingSpeed");
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
if(this.PropertyChanged != null)
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
The new BindingController:
public class BindingController
{
public BindingController()
{
this.Downloads = new ObservableCollection<Download>();
}
public ObservableCollection<Download> Downloads { get; private set; }
}
Setting up the bindings in XAML:
<ListBox Width="Auto"
Name="WebsiteList"
Grid.Column="1"
Grid.Row="2"
Grid.RowSpan="2"
ItemsSource="{Binding Downloads}"
ItemTemplate="{StaticResource DownloadedWebsitesListBox}"
Margin="0,0,0,0">
</ListBox>
Initializing the collection in MainWindow
Download download = new Download();
download.DownloadingSpeed = "40kb/s";
download.WebsiteTitle = "WebsiteTitle";
download.Status = "Downloading";
bc.Downloads.Add(download);
this.DataContext = bc;

Data binding WPF XAML

Hello I am new to WPF and I am not sure how to do the data binding and the code behind to get my textbox and button to be enabled and disabled.
If you could show me how to get it to work in the example below it would help me out in my project.
XAML
<ComboBox Name="ComboBoxA"
Margin="5"
SelectedIndex="0" SelectionChanged="ComboBoxA_SelectionChanged" >
<ComboBox.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel Orientation="Vertical" Height="Auto" Margin="5" />
</ItemsPanelTemplate>
</ComboBox.ItemsPanel>
<ComboBoxItem Content="Option1" Width="72" />
<ComboBoxItem Content="Option2" Width="72" />
<ComboBoxItem Content="Option3" Width="72" />
</ComboBox>
<TextBox Name="TextBoxA"
Margin="5"
Width="200"
IsEnabled="{Binding TextBoxEnabled}" />
<Button Name="ButtonA"
Content="Next"
HorizontalAlignment="left"
Margin="5"
IsEnabled="{Binding ButtonEnabled} />
C#
private void ComboBoxA_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
TextBoxA = new TextBox();
ButtonA = new Button();
if (ComboBoxAfterProcessing.SelectedIndex == 0)
{
TextBoxA.IsEnabled = false;
ButtonA.IsEnabled = false;
}
else if (ComboBoxAfterProcessing.SelectedIndex == 1)
{
TextBoxA.IsEnabled = true;
ButtonA.IsEnabled = true;
}
else if (ComboBoxAfterProcessing.SelectedIndex == 2)
{
TextBoxA.IsEnabled = true;
ButtonA.IsEnabled = true;
}
}

Write a class as follows which shall look like below
public class ViewMole:INotifyPropertyChanged
{
public ViewMole()
{
ListValues = new List<string>() { "Option1", "Option2", "Option3", "Option4",
"Option5" };
}
public ICommand Click
{
get
{
return new RelayCommand();
}
}
public List<string> ListValues
{
get;
set;
}
string a;
public string A
{
get
{
return a;
}
set
{
a = value;
RaisePropertyChanged("A");
}
}
int index=0;
public int SelectedIndex
{
get
{
return index;
}
set
{
index = value;
RaisePropertyChanged("SelectedIndex");
A = ListValues[index];
if (index == 0)
{
IsEnabled = false;
}
else
{
IsEnabled = true;
}
}
}
bool isEnabled;
public bool IsEnabled
{
get
{
return isEnabled;
}
set
{
isEnabled = value;
RaisePropertyChanged("IsEnabled");
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void RaisePropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
Write another class which implements ICommand as below. This is to handel button click events
public class RelayCommand : ICommand
{
public bool CanExecute(object parameter)
{
return true;
}
public event EventHandler CanExecuteChanged;
public void Execute(object parameter)
{
MessageBox.Show("Button cliked");
}
}
Change your Xaml below
<ComboBox Name="ComboBoxA" SelectedIndex="{Binding SelectedIndex, UpdateSourceTrigger=PropertyChanged}" ItemsSource="{Binding ListValues}"/>
<TextBox Name="TextBoxA" Margin="5" Width="200" Text="{Binding A}" IsEnabled="{Binding IsEnabled}"/>
<Button Name="ButtonA" Content="Next" HorizontalAlignment="left" Margin="5" Command="{Binding Click}" IsEnabled="{Binding IsEnabled}"/>
In Xmal.cs set the data Context as beolw
public MainWindow()
{
InitializeComponent();
DataContext = new ViewMole();
}
Refer the below links to understand why INotifyPropertyChanged and ICommand has to be used
http://wpftutorial.net/INotifyPropertyChanged.html
http://msdn.microsoft.com/en-us/library/system.componentmodel.inotifypropertychanged.aspx
http://msdn.microsoft.com/en-us/library/system.windows.input.icommand.aspx

you can binding your textbox and button's IsEnabe Property to the Combox's SelectedIndex
Property and you neednot response to ComboBoxA_SelectionChanged Event. in order to let the
SelectedIndex change your button and textBox's IsEnabe you need a convetor in your binding
for example: