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WPF databinding and refreshing its UI

I've posted the same question before but it wasn't clear (and contained too many self-induced errors in attempt to fix the code) so re-posting it with more details.
So I have "MainUiWindow.xaml" file which uses databinding like this:
<ItemsControl x:Name="gridSettingsMonster" Grid.Row="0" Grid.Column="0" ItemsSource="{Binding SettingsMonster}">
<ItemsControl.ItemTemplate>
<DataTemplate DataType="{x:Type core:Setting}">
<Grid x:Name="gridMonster">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Text="{Binding Label}" IsEnabled="{Binding Enabled}" ToolTip="{Binding Description}" HorizontalAlignment="Left" VerticalAlignment="Center" Margin="10 5 10 5" FontWeight="{Binding Fontweight}" ></TextBlock>
<ts:ToggleSwitch x:Name="toggleSwitchMonsterAll" IsEnabled="{Binding Enabled}" Grid.Row="0" Grid.Column="1" Command ="{Binding TriggerAction}" IsChecked="{Binding Value}" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="5 0 20 2" Foreground="White" UncheckedText="" CheckedText="" UncheckedBorderBrush="#FF333333" CheckedBorderBrush="#FF2D2D30"/>
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
SettingsMonster binding:
SettingsMonster.Add(new Setting(ConfigHelper.Main.Values.Overlay.MonsterWidget.IsVisible, true, "Monster_1", "Monster Widget", "Show/Hide Monsters Widget", new Command(_ =>
{
ConfigHelper.Main.Values.Overlay.MonsterWidget.IsVisible = !ConfigHelper.Main.Values.Overlay.MonsterWidget.IsVisible;
ConfigHelper.Main.Save();
})));
SettingsMonster.Add(new Setting(ConfigHelper.Main.Values.Overlay.MonsterWidget.ShowUnchangedMonsters, ConfigHelper.Main.Values.Overlay.MonsterWidget.IsVisible, "Monster_2", " Show unchanged monsters", "Automatically hide monsters if they are not damaged", new Command(_ =>
{
ConfigHelper.Main.Values.Overlay.MonsterWidget.ShowUnchangedMonsters = !ConfigHelper.Main.Values.Overlay.MonsterWidget.ShowUnchangedMonsters;
ConfigHelper.Main.Save();
})));
And finally, the Setting class:
public class Setting
{
public bool Value { get; set; }
public bool Enabled { get; set; }
public string Name { get; }
public string Label { get; }
public string Description { get; }
public string Checkbox_visibility { get; }
public string Fontweight { get; }
public List<Setting>SubSettings { get; }
public Command TriggerAction { get; }
public Setting(bool value, bool enabled, string name, string label, string description, Command action = null)
{
Value = value;
Enabled = enabled;
Name = name;
Label = label;
Description = description;
SubSettings = new List<Setting>();
TriggerAction = action;
}
}
Problem:
When I run the build and use the "ToggleSwitch" (it's basically a open-source checkbox) to change the value of "ConfigHelper.Main.Values.Overlay.MonsterWidget.IsVisible", it unchecks the UI correctly.
I want this checkbox to control the other checkboxes (i.e. "Monster_2") as well, so that when the main one is turned off, set IsEnabled value for the child checkboxes/textblocks to FALSE.
I got to the stage where if I check off the main one, restart the build, then the child checkboxes/textblocks are all set as IsEnabled=False. However, I want the same to happen in real time (i.e. refresh the UI without having to restart).
Any help would be appreciated.
EDIT 1.
So I have attempted implementing the INotifyPropertyChanged in my Settings class which looks like the following:
public class Setting : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private bool _value;
private bool _enabled;
public bool Value
{
get
{
return _value;
}
set
{
if (_value == value)
return;
_value = value;
OnPropertyChanged(nameof(Enabled));
}
}
public bool Enabled
{
get
{
return _enabled;
}
set
{
if (_enabled == value)
return;
_enabled = value;
OnPropertyChanged(nameof(Enabled));
}
}
protected void OnPropertyChanged(string name)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(name));
}
}
public string Name { get; }
public string Label { get; }
public string Description { get; }
public string Checkbox_visibility { get; }
public string Fontweight { get; }
public List<Setting>SubSettings { get; }
public Command TriggerAction { get; }
public Setting(bool value, bool enabled, string name, string label, string description, Command action = null)
{
Value = value;
Enabled = enabled;
Name = name;
Label = label;
Description = description;
SubSettings = new List<Setting>();
TriggerAction = action;
}
But my UI is still not refreshing yet... any help?

My viewmodel was referencing incorrect variable in the first place.
I have implemented INotifyPropertyChange in my Setting object as below, and also added a command to be run when the checkbox is triggered.
public class Setting : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string name)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(name));
}
}
private bool _value;
private bool _enabled;
public bool Value
{
get
{
return _value;
}
set
{
if (_value == value)
return;
_value = value;
OnPropertyChanged(nameof(Value));
}
}
public bool Enabled
{
get
{
return _enabled;
}
set
{
if (_enabled == value)
return;
_enabled = value;
OnPropertyChanged(nameof(Enabled));
}
}
public string Name { get; }
public string Label { get; }
public string Description { get; }
public string Fontweight { get; }
public List<Setting>SubSettings { get; }
public Command TriggerAction { get; }
public Setting(bool _value, bool _enabled, string name, string label, string description, Command action = null)
{
Value = _value;
Enabled = _enabled;
Name = name;
Label = label;
Description = description;
SubSettings = new List<Setting>();
TriggerAction = action;
}
}

UI won't update, when adding an item to an ObservableCollection with a Command (WPF, C#)

I have a TreeView, where I want to add an item with a right click. Therefore I use a command, to insert a new item.
The problem is now that adding/removing items won't be reflected in the UI and I don't know why.
The ObersavableCollections are hold in a property in my MainWindow
public static ObservableCollection<PlantObject> PlantObjects { get; set; }
The code works the way I want thus if I check the property and the item itself, it will be added but the TreeView will not reflect the changes. This can be shown by setting the ItemsSource of the TreeView null and then again to PlantObjects, which then displays the added item.
I'm pretty sure it the problem is that I add an item to the property "parents". But I don't know how to solve it.
You can see my Xaml and my Class below. NotifyPropertyChanged is implemented.
Thanks for any advice.
XAML
<TreeView Name="ContextTreeView" Margin="0,9.8,0.8,5" Grid.Row="1" Grid.Column="0" ItemsSource="{Binding Source={x:Static local:MainWindow.PlantObjects} }">
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
</Style>
</TreeView.ItemContainerStyle>
<TreeView.Resources>
<HierarchicalDataTemplate DataType="{x:Type local:PlantObject}" ItemsSource="{Binding PlantObjects}" >
<StackPanel Orientation="Horizontal">
<StackPanel.ContextMenu>
<ContextMenu >
<MenuItem Header="Delete" Name="MenuItem_DeleteContextType" Command="{Binding DeleteContextTypeCommand}"/>
<MenuItem Header="Insert new object above" Name="ContextMenuItem_InsertAbovePlantObject" Command="{Binding InsertAboveCommand}"/>
</ContextMenu>
</StackPanel.ContextMenu>
<TextBlock Text="{Binding Name}"/>
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.Resources>
</TreeView>
My Class
public class PlantObject : INotifyPropertyChanged
{
public PlantObject()
{
CreateInsertAboveCommand();
}
private bool _IsSelected;
private PlantObject parent;
private string name;
public byte[] ParentID { get; set; }
public byte[] ChildID { get; set; }
public byte[] ObjectID { get; set; }
private ObservableCollection<PlantObject> plantObjects = new ObservableCollection<PlantObject>();
public PlantObject Parent
{
get
{
return parent;
}
set
{
if (value != parent)
{
parent = value;
NotifyPropertyChanged();
}
}
}
public string Name
{
get
{
return name;
}
set
{
if (value != name)
{
name = value;
NotifyPropertyChanged();
}
}
}
public ObservableCollection<PlantObject> PlantObjects
{
get { return plantObjects; }
set
{
//ignore if values are equal
if (value == plantObjects) return;
plantObjects = value;
NotifyPropertyChanged();
}
}
public bool IsSelected
{
get { return _IsSelected; }
set
{
if (_IsSelected == value) return;
_IsSelected = value;
NotifyPropertyChanged();
}
}
public int? GetPosition(PlantObject plantObject)
{
int count = 0;
foreach (var childObject in this.plantObjects)
{
if (plantObject == childObject)
{
return count;
}
count++;
}
return null;
}
protected void Insert(int position, PlantObject plantObject)
{
Parent.PlantObjects.Insert(position, plantObject);
}
protected void Remove(PlantObject plantObject)
{
Parent.PlantObjects.RemoveAt(Parent.PlantObjects.IndexOf(plantObject));
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
#region commands
#region InsertAbove Command
public ICommand InsertAboveCommand
{
get;
internal set;
}
private bool CanExecuteInsertAboveCommand()
{
return true;
}
private void CreateInsertAboveCommand()
{
InsertAboveCommand = new RelayCommand(InsertAbove);
}
public void InsertAbove(object obj)
{
//this.IsSelected = true;
if (this.parent == null)
{ //highest level
MainWindow.PlantObjects.Insert(MainWindow.PlantObjects.IndexOf(this), new PlantObject {IsSelected = true, Parent = this.Parent });
return;
}
int position = this.parent.GetPosition(this) ?? default(int);
PlantObject newPlantObejct = new PlantObject { Parent = this.Parent, IsSelected = true };
this.Insert(position, newPlantObejct);
}
#endregion
#endregion
}

c# ListView not updating when Property Changed

My UI is not updating when more data is added to the ObservableCollection. The console output says A first chance exception of type 'System.NullReferenceException' occurred. Should I be using Inotifycollectionchanged instead? Here is some of the code:
<ListView x:Name="ListView2" ItemsSource="{Binding Source={x:Static d:GrabUserConversationModel._Conversation}, UpdateSourceTrigger=PropertyChanged}" SelectionChanged="ListView1_SelectionChanged">
UserConversationModel.cs
public class UserConversationModel : INotifyPropertyChanged
{
public UserConversationModel()
{
}
public string Name
{ get; set; }
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(string Obj)
{
if (PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(Obj));
}
}
}
MainWindow.xaml.cs
public partial class MainWindow
{
static GrabUserConversationModel grabUserConversationModel;
public MainWindow()
{
InitializeComponent();
...
}
static void AddData()
{
grabUserConversationModel.Conversation.Add(new UserConversationModel { Name = "TestName" });
}
GrabUserConversationModel.cs
class GrabUserConversationModel
{
public static ObservableCollection<UserConversationModel> _Conversation = new ObservableCollection<UserConversationModel>();
public ObservableCollection<UserConversationModel> Conversation
{
get { return _Conversation; }
set { _Conversation = value; }
}
...

your property ObservableCollection<UserConversationModel> Conversation is not implementing the INotifyPropertyChanged
public ObservableCollection<UserConversationModel> Conversation
{
get { return _Conversation; }
set { _Conversation = value; OnPropertyChanged("Conversation");}
}

WPF MVVM Populate combobox OnPropertyChanged of another combobox

I want to populate my combobox2 after combobox1 selection changed event.
Here's some part of my XAML:
<ComboBox Name="cmbWorkcode"
ItemsSource="{Binding Workcodes}"
DisplayMemberPath="WorkcodeName"
SelectedValuePath="WorkcodeID"
SelectedValue="{Binding Path=WorkcodeId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
<ComboBox Name="cmbProcess"
ItemsSource="{Binding Processes}"
DisplayMemberPath="ProcessName" SelectedValuePath="ProcessId"
SelectedValue="{Binding Path=ProcessId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
Some part of my ViewModel:
class MainWindowViewModel : ObservableObject
{
private ObservableCollection<Workcode> _workcodes = new ObservableCollection<Workcode>();
public ObservableCollection<Workcode> Workcodes
{
get { return _workcodes; }
set
{
_workcodes = value;
OnPropertyChanged("Workcodes");
}
}
private int _workcodeId;
public int WorkcodeId
{
get { return _workcodeId; }
set
{
_workcodeId = value;
OnPropertyChanged("WorkcodeId");
}
}
private ObservableCollection<Process> _processes = new ObservableCollection<Process>();
public ObservableCollection<Process> Processes
{
get { return _processes; }
set
{
_processes = value;
OnPropertyChanged("Processes");
}
}
private int _processId;
public int ProcessId
{
get { return _processId; }
set
{
_processId = value;
OnPropertyChanged("ProcessId");
}
}
public MainWindowViewModel()
{
PopulateWorkcode();
}
private void PopulateWorkcode()
{
using (var db = new DBAccess())
{
db.ConnectionString = ConfigurationManager.ConnectionStrings["connString"].ConnectionString;
db.Query = #"SELECT workcodeId, workcode FROM workcode";
DataTable data = db.GetData();
if (data != null)
{
foreach (DataRow row in data.Rows)
{
int workcodeId = Convert.ToInt32(row["workcodeId"].ToString());
string workcodeName = row["workcode"].ToString();
_workcodes.Add(new Workcode(workcodeId, workcodeName));
}
}
}
}
private void PopulateProcess()
{
using (var db = new DBAccess())
{
db.ConnectionString = ConfigurationManager.ConnectionStrings["connString"].ConnectionString;
db.Query = #"SELECT ProcessId, ProcessName FROM `process` WHERE WorkcodeId = #workcodeId";
DataTable data = db.GetData(new[] {new MySqlParameter("#workcodeId", _workcodeId.ToString())});
if (data != null)
{
foreach (DataRow row in data.Rows)
{
int id = Convert.ToInt32(row["ProcessId"].ToString());
string name = row["ProcessName"].ToString();
_processes.Add(new Process(id, name));
}
}
}
}
}
My problem is I don't know where do I trigger my PopulateProcess() method so that my combobox2 will be populated base on the selection of combobox1. Thanks for all the time and help! :)
--EDIT--
public class ObservableObject : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
var handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
public class Workcode
{
public int WorkcodeId { get; set; }
public string WorkcodeName { get; set; }
public Workcode(int id, string name)
{
WorkcodeId = id;
WorkcodeName = name;
}
}

initially the second combobox is empty and on select of the first combobox changed just pupulate the process
private int _workcodeId;
public int WorkcodeId
{
get { return _workcodeId; }
set
{
_workcodeId = value;
OnPropertyChanged("WorkcodeId");
if(WorkcodeID>0) PopulateProcess();
}
}

I can understand you want to have the next combobox to fill with data based on the previous value. Since i don't have classes of your type, i will give a simple example,
class ItemListViewModel<T> : INotifyPropertyChanged where T : class
{
private T _item;
private ObservableCollection<T> _items;
public ItemListViewModel()
{
_items = new ObservableCollection<T>();
_item = null;
}
public void SetItems(IEnumerable<T> items)
{
Items = new ObservableCollection<T>(items);
SelectedItem = null;
}
public ObservableCollection<T> Items
{
get { return _items; }
private set
{
_items = value;
RaisePropertyChanged("Items");
}
}
public T SelectedItem
{
get { return _item; }
set
{
_item = value;
RaisePropertyChanged("SelectedItem");
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void RaisePropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
Then have the main viewmodel that will be bound to the DataContext of the view. Have the Load methods do what you want
class MyViewModel : INotifyPropertyChanged
{
public MyViewModel()
{
First = new ItemListViewModel<string>();
Second = new ItemListViewModel<string>();
Third = new ItemListViewModel<string>();
First.PropertyChanged += (s, e) => Update(e.PropertyName, First, Second, LoadSecond);
Second.PropertyChanged += (s, e) => Update(e.PropertyName, Second, Third, LoadThird);
LoadFirst();
}
public ItemListViewModel<string> First { get; set; }
public ItemListViewModel<string> Second { get; set; }
public ItemListViewModel<string> Third { get; set; }
private void LoadFirst()
{
First.SetItems(new List<string> { "One", "Two", "Three" });
}
private void LoadSecond()
{
Second.SetItems(new List<string> { "First", "Second", "Third" });
}
private void LoadThird()
{
Third.SetItems(new List<string> { "Firsty", "Secondly", "Thirdly" });
}
private void Update<T0, T1>(string propertyName, ItemListViewModel<T0> parent, ItemListViewModel<T1> child, Action loadAction)
where T0 : class
where T1 : class
{
if (propertyName == "SelectedItem")
{
if (parent.SelectedItem == null)
{
child.SetItems(Enumerable.Empty<T1>());
}
else
{
loadAction();
}
}
}
public event PropertyChangedEventHandler PropertyChanged;
}
In XAML,
<ComboBox ItemsSource="{Binding First.Items}" SelectedItem="{Binding First.SelectedItem}" />
<ComboBox ItemsSource="{Binding Second.Items}" SelectedItem="{Binding Second.SelectedItem}" />
<ComboBox ItemsSource="{Binding Third.Items}" SelectedItem="{Binding Third.SelectedItem}" />

The issue is here
<ComboBox Name="cmbWorkcode"
ItemsSource="{Binding Workcodes}"
DisplayMemberPath="WorkcodeName"
SelectedValuePath="WorkcodeId"
SelectedValue="{Binding Path=WorkcodeId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
It should be WorkcodeId instead of WorkcodeID. rest you can try as Nishanth replied
public int WorkcodeId
{
get { return _workcodeId; }
set
{
if(_workcodeId !=value)
{
_workcodeId = value;
OnPropertyChanged("WorkcodeId");
PopulateProcess();
}
}
}

WPF DataGrid-DataGridCheckBoxColumn vs2010 c# .net

I am working in vs2010.
I have created a DataGrid which is bounded to
ObservableCollection List;
the Class_CMD looks like this :
public class Class_RetrieveCommand
{
public string CMD { get; set; }
public bool C_R_CMD { get; set; }
public bool S_CMD { get; set; }
public bool C_S_CMD { get; set; }
}
i have 4 delegates which i pass to another window, and this window needs to update the list during runtime. During the runtime i can see the string column of the grid updated all the time but the DataGridCheckBoxColumns are never updated.
the DataGrid -
<DataGrid Background="Transparent" x:Name="DataGrid_CMD" Width="450" MaxHeight="450" Height="Auto" ItemsSource="{Binding}" AutoGenerateColumns="True">
one of the delegates which updates the bool is -
public void UpdateC_S_CMD(string Msg)
{
foreach (Class_CMD c in List.ToArray())
{
if (c.CMD.Equals(Msg))
c.C_S_CMD = true;
}
}
I don't understand why the bool columns are not updated....
can anyone help please?
thanks.

Your class Class_RetrieveCommand needs to implement the INotifyPropertyChanged interface. Otherwise the individual rows databound to the instances of the class don't know that the underlying properties have changed. If you change it to something like this, you should see the changes reflected in your grid:
public class Class_RetrieveCommand : INotifyPropertyChanged
{
private bool _cRCmd;
private bool _cSCmd;
private string _cmd;
private bool _sCmd;
public string CMD
{
get { return _cmd; }
set
{
_cmd = value;
InvokePropertyChanged(new PropertyChangedEventArgs("CMD"));
}
}
public bool C_R_CMD
{
get { return _cRCmd; }
set
{
_cRCmd = value;
InvokePropertyChanged(new PropertyChangedEventArgs("C_R_CMD"));
}
}
public bool S_CMD
{
get { return _sCmd; }
set
{
_sCmd = value;
InvokePropertyChanged(new PropertyChangedEventArgs("S_CMD"));
}
}
public bool C_S_CMD
{
get { return _cSCmd; }
set
{
_cSCmd = value;
InvokePropertyChanged(new PropertyChangedEventArgs("C_S_CMD"));
}
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
#endregion
public void InvokePropertyChanged(PropertyChangedEventArgs e)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, e);
}
}
}

You should implement INotifyPropertyChanged in the Class_RetrieveCommand like this:
public class Class_RetrieveCommand : INotifyPropertyChanged
{
private string _CMD;
public string CMD
{
get { return _CMD; }
set { _CMD = value; OnPropertyChanged("CMD"); }
}
... similar for the other properties
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
var handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
Unfortunately you can't use auto properties anymore then (except you resort to proxygenerators).