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Notifying that a RadioButton has been selected in a UserControl in WPF

I am trying to make a button in a viewmodel recognize that a radio button in another view model (a UserControl that is activated on the first viewmodel) has been selected, thus enabling the button in the first viewmodel.
I have a UserControl AlbumsDisplayViewModel within my base view model BaseViewModel.
In BaseView XAML There's a button (OpenAlbum) which is supposed to be enabled when a radio button on the AlbumsDisplayView is selected (see CanOpenAlbum).
BaseView XAML:
<Canvas x:Name="cnvsInputWrapper" Background="LightGray"
Grid.Column="4" Grid.Row="1" Grid.RowSpan="4"
Margin="5">
<Canvas.OpacityMask>
<VisualBrush Visual="{Binding ElementName=maskRoundEdges}" />
</Canvas.OpacityMask>
<DockPanel Margin="15, 25">
<ContentControl x:Name="ActiveItem" />
</DockPanel>
</Canvas>
<!-- Action Buttons section -->
<Grid Grid.Row="3" Grid.Column="1" Grid.RowSpan="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="12" />
<ColumnDefinition Width="auto" />
<ColumnDefinition Width="auto" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="12" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="12" />
<RowDefinition Height="auto" />
<RowDefinition Height="auto" />
<RowDefinition Height="*" />
<RowDefinition Height="12" />
</Grid.RowDefinitions>
<Button Grid.Row="1" Grid.Column="1" x:Name="OpenAlbum"
IsEnabled="{Binding CanOpenAlbum}">
<StackPanel Orientation="Vertical">
<TextBlock>Open</TextBlock>
<TextBlock>Album</TextBlock>
</StackPanel>
</Button>
</Grid>
BaseViewModel C#:
public class BaseViewModel : Conductor<object>
{
private AlbumsDisplayViewModel m_vmAlbumsDisplay; // Initialized in another function.
public BaseViewModel()
{
}
public bool CanOpenAlbum() => (m_vmAlbumsDisplay != null) && (m_vmAlbumsDisplay.GetSelectedAlbum() != null);
public void OpenAlbum()
{
AlbumModel album = m_vmAlbumsDisplay.GetSelectedAlbum();
//ActivateItem(/*albumViewModel(album)*/);
}
}
AlbumsDisplayView XAML:
<ItemsControl x:Name="Albums" FlowDirection="LeftToRight"
Margin="10, 0">
<ItemsControl.ItemTemplate>
<DataTemplate DataType="{x:Type vms:AlbumViewModel}">
<StackPanel Orientation="Horizontal" Margin="0, 5">
<RadioButton GroupName="rdbtnAlbums"
IsChecked="{Binding IsSelected}" />
<!-- Album Details -->
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
AlbumsDisplayViewModel C#:
class AlbumsDisplayViewModel : Screen
{
private ObservableCollection<AlbumViewModel> m_albums;
public AlbumsDisplayViewModel()
{
}
public ObservableCollection<AlbumViewModel> Albums
{
get { return m_albums; }
set
{
m_albums = value;
NotifyOfPropertyChange(() => Albums);
}
}
public AlbumModel GetSelectedAlbum()
{
AlbumModel res = null;
foreach (var vmAlbum in Albums)
{
if (vmAlbum.IsSelected)
{
res = vmAlbum.Album;
break;
}
}
return res;
}
}
And last, AlbumViewModel C#:
class AlbumViewModel : Screen
{
private AlbumModel m_albumModel;
private bool m_isSelected;
public AlbumViewModel(AlbumModel albumModel)
{
m_albumModel = albumModel;
}
public AlbumModel Album
{
get { return m_albumModel; }
set
{
m_albumModel = value;
NotifyOfPropertyChange(() => Album);
}
}
public bool IsSelected
{
get { return m_isSelected; }
set
{
m_isSelected = value;
NotifyOfPropertyChange(() => IsSelected);
}
}
}
I expected that when IsSelected in AlbumViewModel is changed (when the user selects a radio button), the OpenAlbum button will be enabled, because CanOpenAlbum will return true, but I have realized that CanOpenAlbum wasn't even called for some reason. What do I need to do so CanOpenAlbum will be notified to be called whenever a radio button is selected?

After searching for an answer for a long time, I decided that it will be better to search for a better solution, instead of an answer. I've discovered that a ListBox element has a SelectedItem property, which eliminates the need for radio buttons.
Eventually, I replaced the ItemsControl with a ListBox, and I;m happy with the results.
AlbumDisplayView XAML (only this has changed):
<ScrollViewer x:Name="Scroller" Height="300"
FlowDirection="RightToLeft">
<ListBox x:Name="Albums" FlowDirection="LeftToRight"
Background="Transparent" Margin="10, 0"
BorderThickness="0" SelectedItem="{Binding SelectedAlbum}">
<ItemsControl.ItemTemplate>
<DataTemplate DataType="{x:Type vms:AlbumViewModel}">
<StackPanel Orientation="Horizontal" Margin="0, 5">
<!-- Album Details -->
<StackPanel Orientation="Vertical">
<StackPanel Grid.Row="1" Grid.Column="1"
Orientation="Horizontal" Margin="12, 0">
<TextBlock Text="{Binding Album.Name}" />
<TextBlock Text=" - User#" />
<TextBlock Text="{Binding Album.OwnerID}" />
</StackPanel>
<TextBlock Text="{Binding Album.CreationDate}"
FontSize="12" Margin="12, 0" />
</StackPanel>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ListBox>
</ScrollViewer>

How can I use 2 data bindings for an ItemSource Data Template in WPF App

I have a counter which increments depending on a foreach Loop from:
public partial class UserControlCounter : UserControl, INotifyPropertyChanged
{
private int _scanStatusCounter;
public int ScanStatusCounter
{
get { return _scanStatusCounter; }
set { _scanStatusCounter = value; NotifyPropertyChanged(); }
}
public UserControlCounter()
{
InitializeComponent();
DataContext = this;
}
private async void Button_Click(object sender, RoutedEventArgs e)
{
await Task.Run(getAll);
scanStatus.Text = "Persons " + ScanStatusCounter.ToString();
}
private async void getAll()
{
//grab data and iterate it
string[] string_array = new string[] { "a", "b", "c", "d", "e" }; // type = System.String[]
foreach (var i in string_array)
{
ScanStatusCounter++;
await Task.Delay(100);
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
and the Xaml:
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="150"/>
<ColumnDefinition Width="auto"/>
<ColumnDefinition Width="auto"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="60"/>
</Grid.RowDefinitions>
<ListBox Grid.Row="0" Grid.Column="0" Name="myListBox" Height="40" ></ListBox>
<TextBlock Grid.Row="0" Grid.Column="1" Name="scanStatus" Height="40" Text="{Binding Path=ScanStatusCounter, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"></TextBlock>
<Button Grid.Row="0" Grid.Column="2" Click="Button_Click" Height="40">Click Me</Button>
</Grid>
That works fine and increments "live", but my problem is that I need to get that now running inside a more complex Data Template.
I've tried to inject the Counter onClick with:
private async void Button_Click(object sender, RoutedEventArgs e)
{
var btn = sender as Button;
var contentPresenter = (btn.TemplatedParent as ContentPresenter);
var ppStatusCounter = contentPresenter.ContentTemplate.FindName("scanStatus", contentPresenter) as TextBlock;
ppStatusCounter.Text = "Entrys found: " + ScanStatusCounter.ToString();
}
But then I get the Value only onClick not like a live incrementing Counter, that's my Data Template:
<UserControl.Resources>
<c1:NameList x:Key="NameListData"/>
<DataTemplate x:Key="NameItemTemplate">
<Grid Margin="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto"/>
<ColumnDefinition Width="100" />
<ColumnDefinition Width="100" />
<ColumnDefinition Width="100" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="40"></RowDefinition>
<RowDefinition Height="40"></RowDefinition>
</Grid.RowDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Text="Domaine"/>
<TextBox Grid.Row="1" Grid.Column="0" x:Name="txtDomainName" Text="{Binding Path=DomaineName}" Margin="0,0,5,0"></TextBox>
<Button Grid.Row="1" Grid.Column="1" Width="100" Height="30" Margin="5,5,5,5" x:Name="btnNames" Click="Button_Click" Content="Start Scan" />
<Grid Grid.Column="2" Grid.Row="1" Height="20">
<ProgressBar x:Name="pbStatus" Height="20" Width="100" Minimum="0" Maximum="100" Visibility="Hidden"/>
<TextBlock x:Name="pbStatusText" HorizontalAlignment="Center" VerticalAlignment="Center" Text="Scanning" Visibility="Hidden"/>
</Grid>
<TextBlock Grid.Column="3" Grid.Row="1" Name="scanStatus" Text="{Binding Path=ScanStatusCounter, UpdateSourceTrigger=PropertyChanged}"/>
</Grid>
</DataTemplate>
</UserControl.Resources>
<Grid>
<StackPanel Orientation="Horizontal" VerticalAlignment="top">
<StackPanel Orientation="Horizontal" Margin="0,20,0,0">
<ListBox x:Name="lstDomainNames"
Margin="5,5,5,5"
ItemsSource="{Binding Source={StaticResource NameListData}}"
ItemTemplate="{StaticResource NameItemTemplate}"
IsSynchronizedWithCurrentItem="True"/>
</StackPanel>
</StackPanel>
</Grid>
that's my Data Source Class, not much there:
public partial class NameList : ObservableCollection<SetCredentials>
{
private static Logger logger = LogManager.GetCurrentClassLogger();
public NameList() : base()
{
using var forest = Forest.GetCurrentForest();
Forest currentForest = Forest.GetCurrentForest();
DomainCollection domains = currentForest.Domains;
foreach (Domain objDomain in domains)
{
Add(new SetCredentials(objDomain.ToString()));
}
}
}
public class SetCredentials
{
private string domainName;
public SetCredentials(string domain)
{
this.domainName = domain;
}
public string DomaineName
{
get { return domainName; }
set { domainName = value; }
}
}
Do I have to add a second Data Binding source to my ItemSource or do I need another approach for this, for example in my TextBox Binding?

Access Custom Class Variables in a ViewModel through binding

What I want to do is to be able to access an object's properties through a bound textblock that is found in a viewModel class. So say I want to access the OrderID of the Orders class in a bound textblock that is stored in a viewModel class.
What I have for that is:
<textblock text="{Binding Path=Order.OrderID}"/>
This is connected to the order's orderID as when I change the OrderID in the ViewModel class the change is reflected in the textblock. The problem occurs when I try to load the OrderID from another class.
The Other class:
public class ModifyOrder
{
private ViewModel boundData;
public ModifyOrder()
{
boundData = new ViewModel();
}
public void ChangeOrderID()
{
boundData.Order.OrderID = 10;
}
}
The changes here don't get transfered to the static _Order in the ViewModel class.
This is the viewModel class:
public class ViewModel : INotifyPropertyChanged
{
private Orders _Order;
public Orders Order
{
get { return _Order; }
set
{
if (_Order != value)
{
_Order = value;
}
}
}
public ViewModel()
{
Order = new Orders();
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
I have the ViewModel class loaded into the UI's DataContext and my other bound variables in the ViewModel class work fine but for some reason either the bound textblock isn't accessing the Order.OrderID (Which I don't think is the problem since I can modify the Order.OrderID in the ViewModel class and the changes are reflected) OR the class that's modifying my Order isn't able to modify the OrderID.
I've already tried to load a new Order class with the new OrderID and then try to load the ViewModel's _Order with the ModifyOrder's new Order but that hasn't worked out either.
This is the Orders class:
public class Orders : INotifyPropertyChanged
{
private int _OrderID;
public int OrderID
{
get { return _OrderID; }
set
{
if(_OrderID != value)
{
_OrderID = Value
OnPropertyChanged(nameof(OrderID));
}
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
<Page x:Class="SPWally.FunctionalPages.LookupOrders"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:SPWally.FunctionalPages"
mc:Ignorable="d"
d:DesignHeight="450" d:DesignWidth="800"
Title="LookupOrders">
<Grid Background="AliceBlue">
<Grid.RowDefinitions>
<RowDefinition Height="50"/>
<RowDefinition Height="30"/>
<RowDefinition Height="*"/>
<RowDefinition Height="20"/>
<RowDefinition Height="20"/>
<RowDefinition Height="20"/>
<RowDefinition Height="20"/>
<RowDefinition Height="20"/>
<RowDefinition Height="20"/>
<RowDefinition Height="*"/>
<RowDefinition Height="50"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2" HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="30" Text="Search For Order" />
<TextBlock Grid.Row="1" Grid.Column="0" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="0,0,335,0" Text="OrderID: " />
<TextBox Grid.Row="1" Grid.Column="0" HorizontalAlignment="Right" VerticalAlignment="Center" Width="300" Margin="0,0,20,0" Text="{Binding Path=OrderIDSearch, Mode=OneWayToSource, UpdateSourceTrigger=PropertyChanged}" />
<Button Grid.Row="1" Grid.Column="1" HorizontalAlignment="Left" VerticalAlignment="Center" Width="40" Height="20" Margin="10,0,0,0" Content="Find" Click="Find_Click" />
<Button Grid.Row="1" Grid.Column="1" HorizontalAlignment="Left" VerticalAlignment="Center" Width="50" Height="20" Margin="70,0,0,0" Content="Refund" Click="Refund_Click" />
<TextBlock Grid.Row="3" Grid.Column="0" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="0,0,100,0" Text="OrderID:"/>
<TextBlock Grid.Row="4" Grid.Column="0" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="0,0,100,0" Text="Customer:"/>
<TextBlock Grid.Row="5" Grid.Column="0" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="0,0,100,0" Text="Product:"/>
<TextBlock Grid.Row="6" Grid.Column="0" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="0,0,100,0" Text="Branch:"/>
<TextBlock Grid.Row="7" Grid.Column="0" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="0,0,100,0" Text="Sales Price:"/>
<TextBlock Grid.Row="8" Grid.Column="0" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="0,0,100,0" Text="Quantity:"/>
<TextBlock Grid.Row="3" Grid.Column="0" Grid.ColumnSpan="2" HorizontalAlignment="Center" VerticalAlignment="Center" Width="200" Margin="30,0,0,0" Text="{Binding Path=Order.OrderID, Mode=TwoWay}"/>
<TextBlock Grid.Row="4" Grid.Column="0" Grid.ColumnSpan="2" HorizontalAlignment="Center" VerticalAlignment="Center" Width="200" Margin="30,0,0,0" Text="{Binding Path=Order.Customer.FullName, Mode=TwoWay}"/>
<TextBlock Grid.Row="5" Grid.Column="0" Grid.ColumnSpan="2" HorizontalAlignment="Center" VerticalAlignment="Center" Width="200" Margin="30,0,0,0" Text="{Binding Path=Order.Product.ProductName, Mode=TwoWay}"/>
<TextBlock Grid.Row="6" Grid.Column="0" Grid.ColumnSpan="2" HorizontalAlignment="Center" VerticalAlignment="Center" Width="200" Margin="30,0,0,0" Text="{Binding Path=Order.Branch.BranchName, Mode=TwoWay}"/>
<TextBlock Grid.Row="7" Grid.Column="0" Grid.ColumnSpan="2" HorizontalAlignment="Center" VerticalAlignment="Center" Width="200" Margin="30,0,0,0" Text="{Binding Path=Order.SalesPrice, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
<TextBlock Grid.Row="8" Grid.Column="0" Grid.ColumnSpan="2" HorizontalAlignment="Center" VerticalAlignment="Center" Width="200" Margin="30,0,0,0" Text="{Binding Path=Order.Stocks, Mode=TwoWay}"/>
<Button Grid.Row="10" Grid.Column="0" Grid.ColumnSpan="2" HorizontalAlignment="Center" VerticalAlignment="Center" Width="60" Height="25" Content="Cancel" Command="{x:Static NavigationCommands.BrowseBack}" />
</Grid>
</Page>
Keep in mind that I've literally learned everything I know about data binding in the last 48 hours so bear with me here.
Any kind of help at all is very much appreciated. Thank!

You need to implement INotifyPropertyChanged in Orders class.
You need to Invoke OnPropertyChanged() inside all setters.

Where your view model is getting instantiated ? I guess since you are recreating your viewmodel instance in ModifyOrder class
boundData = new ViewModel();
binding is lost and may be because of that its not showing up .

...Yeah, so. It was the
public ViewModel()
{
Order = new Order();
}
that was wiping clean the private static Orders _Order in the ViewModel class every time it was instantiated so I changed it to
public ViewModel()
{
if (_Order == null)
{
Order = new Order();
}
}
and that fixed the problem...
Thanks to everyone that helped me out with this! I learned a lot from you all!
I'm going to go cry myself to sleep now <3

WPF MVVM properties binding not working properly

I have created a view model which has a single property for a student model, that I am then binding to a control in my XAML. But nothing is appearing when I execute the application.
I am setting data context in my app.xaml.cs as follows:
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
Registrationformusinemvvm.MainWindow window = new MainWindow();
VMUser VM = new VMUser();
window.DataContext = VM;
window.Show();
}
Why is the binding not working?
This is my view model:
public class VMUser:BaseClass
{
private student _currentStudent;
public student CurrentStudent
{
get { return _currentStudent; }
set {
_currentStudent = value;
OnPropertyChanged("CurrentStudent");
}
}
}
My Student model class:
public class student:BaseClass
{
private string name="sumit";
public string Name
{
get { return name; }
set { name = value; OnPropertyChanged("Name"); }
}
private int rollNum;
public int RollNum
{
get { return rollNum; }
set { rollNum = value;OnPropertyChanged("RollNum"); }
}
private int phNum;
public int PhNum
{
get { return phNum; }
set { phNum = value;OnPropertyChanged("PhNum"); }
}
private string sub;
public string Sub
{
get { return sub; }
set { sub = value;OnPropertyChanged("Sub"); }
}
}
My XAML:
<Window x:Class="Registrationformusinemvvm.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:Registrationformusinemvvm"
xmlns:vm="clr-namespace:Registrationformusinemvvm.ViewModel"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<!--<Window.DataContext>
<vm:VMUser/>
</Window.DataContext>-->
<Window.Resources>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200"/>
<ColumnDefinition Width="200"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Text="Name" Grid.Column="0" Grid.Row="0" FontSize="14"
FontWeight="Bold" VerticalAlignment="Center"
HorizontalAlignment="Center"/>
<TextBlock Text="Roll Number" Grid.Column="0" Grid.Row="1" FontSize="14"
FontWeight="Bold" VerticalAlignment="Center"
HorizontalAlignment="Center"/>
<TextBlock Text="Subject" Grid.Column="0" Grid.Row="2" FontSize="14"
FontWeight="Bold" VerticalAlignment="Center"
HorizontalAlignment="Center"/>
<TextBlock Text="Phone Number" Grid.Column="0" Grid.Row="3"
FontSize="14" FontWeight="Bold" VerticalAlignment="Center"
HorizontalAlignment="Center"/>
<TextBox Name="tbName" Text="{Binding CurrentStudent.Name,Mode=TwoWay,
UpdateSourceTrigger=PropertyChanged}" Grid.Column="1" Grid.Row="0"
Width="120" Height="30" HorizontalAlignment="Center"
VerticalAlignment="Center"/>
<TextBox Name="tbRollnum" Text="{Binding CurrentStudent.RollNum}"
Grid.Column="1" Grid.Row="1" Width="120" Height="30"
HorizontalAlignment="Center" VerticalAlignment="Center"/>
<TextBox Name="tbSub" Text="{Binding CurrentStudent.Sub}"
Grid.Column="1" Grid.Row="2" Width="120" Height="30"
HorizontalAlignment="Center" VerticalAlignment="Center"/>
<TextBox Name="tbPh" Text="{Binding CurrentStudent.PhNum}"
Grid.Column="1" Grid.Row="3" Width="120" Height="30"
HorizontalAlignment="Center" VerticalAlignment="Center"/>
<Button Name="tbSubmit" Content="Submit" Grid.ColumnSpan="3"
Grid.Row="4" Height="30" Width="100" HorizontalAlignment="Center"/>
</Grid>
</Window>

My guess is that your binding isn't working because your _currentStudent is null by default. Initialize your _currentStudent if null.
public student CurrentStudent
{
get { return _currentStudent = (_currentStudent ?? new student()); }
set
{
_currentStudent = value; OnPropertyChanged("CurrentStudent");
}
}

You need to add OnPropertyChanged in your model class.
void OnPropertyChanged(string prop)
{
if (this.PropertyChanged != null)
this.PropertyChanged(this, new PropertyChangedEventArgs(prop));
}
public event PropertyChangedEventHandler PropertyChanged;

As per your above code you cant assigned the value to CurrentStudent Property so
can you please check do you have the value to CurrentStudent property.
Thank you for your question

Remove StartupUri="YourXamlFile.xaml" from App.Xaml

Stop ContentTemplate Selector invoke on TabControl selection change event

I have a TabControl. Each tab Item i.e newly added Tab is rendered using content template selector. But each time i switch between the tabs, content template selector is getting called.
I wanted to stop this. This is because, In the in Tabcontrol, User have provided actions to change the layout, since in the selection change event of the tab Item content template is getting called, it is getting difficult for me to retain the layout what user has changed during Tab Item Selection change Event.
Following is code i am using for the TabControl
<TabControl Grid.Column="2" x:Name="MainTabControl" HorizontalAlignment="Stretch" Margin="0,12,0,7"
SelectedItem="{Binding SelectedTabItem}"
Visibility="{Binding TabsVisible}"
ItemsSource="{Binding ToolsList,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
ItemTemplate="{StaticResource ToolDisplayDataTemplate}"
commands:FrameworkUICommandList.TabItemChangedCommand="{Binding Path=TabItemChangedCommand}"
>
<TabControl.ContentTemplate>
<DataTemplate>
<ContentControl Content="{Binding}" ContentTemplateSelector="{DynamicResource toolTabDataItemTemplateSelector}"/>
</DataTemplate>
</TabControl.ContentTemplate>
<TabControl.ItemContainerStyle>
<Style TargetType="TabItem" BasedOn="{StaticResource TabItemStyle}">
<Setter Property="AutomationProperties.AutomationId" Value="{Binding ToolID}" />
<Setter Property="ToolTip" Value="{Binding ToolID,Converter={StaticResource ResourceKey=tabItemTooltipConverter}}"/>
</Style>
</TabControl.ItemContainerStyle>
</TabControl>
UPDATE : I have created a sample project to explain my problem. Could not share the project anywhere, so updating the code snippet in main question. sorry for that.
In the sample project, user can add TabItem dynamically to TabControl. Eash Tabcontent can show two Grid panel and they are separated by Grid Splitter. Display of second grid is Based on some flag (in this example ShowSecondPanel). If user click on "Show / Hide Second Panel" button, then second panel content will be shown for the current selected tab.
The Problem is, user can re-size the panels using Grid Splitter, but when user navigates to some other tab and comes back to previous one, the grid splitter position changes to original position.
Hope I am clear on describing the problem.
Code for MainWindow.xaml
<Window x:Class="TabControlTestApp.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:TabControlTestApp"
Title="MainWindow" Height="500" Width="700">
<Window.DataContext>
<local:MainWindowViewModel />
</Window.DataContext>
<Window.Resources>
<local:TabContentTemplateSelector x:Key="tabContentTemplateSelector" />
<DataTemplate x:Key="TabitemDataTemplate">
<StackPanel Width="50" Height="50">
<TextBlock Text="{Binding TabFirstPanel.Name}"></TextBlock>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="TabContentWithFirstPanel">
<Grid>
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0">Name :</TextBlock>
<TextBlock Grid.Row="0" Grid.Column="1" Text="{Binding TabFirstPanel.Name}"></TextBlock>
</Grid>
</DataTemplate>
<DataTemplate x:Key="TabContentWithBothPanel">
<Grid>
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200"></ColumnDefinition>
<ColumnDefinition Width="5"></ColumnDefinition>
<ColumnDefinition Width="Auto"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid Grid.Row="0" Grid.Column="0">
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0">Name :</TextBlock>
<TextBlock Grid.Row="0" Grid.Column="1" Text="{Binding TabFirstPanel.Name}"></TextBlock>
</Grid>
<GridSplitter Grid.Row="0" Grid.Column="1"
VerticalAlignment="Stretch"
Width="5"
Height="Auto"
ResizeDirection="Columns"
ResizeBehavior="PreviousAndNext"
></GridSplitter>
<Grid Grid.Row="0" Grid.Column="2">
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0">Additional Detail :</TextBlock>
<TextBlock Grid.Row="0" Grid.Column="1" Text="{Binding TabSecondPanel.AdditionalDetails}"></TextBlock>
</Grid>
</Grid>
</DataTemplate>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="50"></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="150"></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
</Grid.ColumnDefinitions>
<StackPanel Grid.Row="1" Grid.Column="0">
<Button Content="Load Tab : 1" Name="LoadTab1" Width="100" Height="50" Command="{Binding LoadTabCommand}" CommandParameter="{Binding ElementName=LoadTab1}"></Button>
<Button Content="Load Tab : 2" Name="LoadTab2" Width="100" Height="50" Command="{Binding LoadTabCommand}" CommandParameter="{Binding ElementName=LoadTab2}"></Button>
<Button Content="Load Tab : 3" Name="LoadTab3" Width="100" Height="50" Command="{Binding LoadTabCommand}" CommandParameter="{Binding ElementName=LoadTab3}"></Button>
</StackPanel>
<Button Content="Close All tab" Width="100" Height="40" x:Name="CloseAllTab"></Button>
<Button Content="Show / Hide Second Panel" x:Name="ShowHideSecondPanelInTab"
Grid.Row="0" Grid.Column="1" Width="150"
Command="{Binding LoadTabCommand}" CommandParameter="{Binding ElementName=ShowHideSecondPanelInTab}"></Button>
<TabControl Grid.Row="1" Grid.Column="1"
ItemsSource="{Binding TabContentList,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
SelectedItem="{Binding SelectedTabItem}"
ItemTemplate="{StaticResource ResourceKey=TabitemDataTemplate}"
ContentTemplateSelector="{StaticResource ResourceKey=tabContentTemplateSelector}"
>
</TabControl>
</Grid>
</Window>
Code For MainWindowViewModel
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Input;
using System.ComponentModel;
using System.Collections.ObjectModel;
namespace TabControlTestApp
{
class MainWindowViewModel : INotifyPropertyChanged
{
public MainWindowViewModel()
{
this.loadTabCommand = new LoadTabCommand(this);
tabContentList = new ObservableCollection<TabContent>();
}
public ICommand LoadTabCommand
{
get
{
return this.loadTabCommand;
}
set
{
this.loadTabCommand = value;
}
}
public ObservableCollection<TabContent> TabContentList
{
get
{
return tabContentList;
}
set
{
tabContentList = value;
OnPropertyChanged("TabContentList");
}
}
public TabContent SelectedTabItem
{
get
{
return selectedTabItem;
}
set
{
selectedTabItem = value;
OnPropertyChanged("SelectedTabItem");
}
}
public void LoadFirstTab()
{
TabFirstPanel firstPanel = new TabFirstPanel() { Name = "John-1", Age = "31" };
TabSecondPanel secondPanel = new TabSecondPanel() { AdditionalDetails="Some Details for First Tab" };
TabContent firstTabContent = new TabContent() { TabFirstPanel = firstPanel, TabSecondPanel = secondPanel, ShowSecondPanel = false };
tabContentList.Add(firstTabContent);
SelectedTabItem = firstTabContent;
}
public void LoadSecondTab()
{
TabFirstPanel firstPanel = new TabFirstPanel() { Name = "John-2", Age = "31" };
TabSecondPanel secondPanel = new TabSecondPanel() { AdditionalDetails = "Some Details for second Tab" };
TabContent secondTabContent= new TabContent() { TabFirstPanel = firstPanel, TabSecondPanel = secondPanel, ShowSecondPanel=false };
tabContentList.Add(secondTabContent);
SelectedTabItem = secondTabContent;
}
public void LoadThirdTab()
{
TabFirstPanel firstPanel = new TabFirstPanel() { Name = "John-3", Age = "31" };
TabSecondPanel secondPanel = new TabSecondPanel() { AdditionalDetails = "Some Details for Third Tab" };
TabContent ThirdTabContent = new TabContent() { TabFirstPanel = firstPanel, TabSecondPanel = secondPanel, ShowSecondPanel = false };
tabContentList.Add(ThirdTabContent);
SelectedTabItem = ThirdTabContent;
}
public void ShowHideSecondPanelInTab()
{
TabContent currentTabContent = SelectedTabItem;
int currentIndex = tabContentList.IndexOf(SelectedTabItem);
if (currentTabContent.ShowSecondPanel)
{
currentTabContent.ShowSecondPanel = false;
}
else
{
currentTabContent.ShowSecondPanel = true;
}
TabContentList.RemoveAt(currentIndex);
TabContentList.Insert(currentIndex, currentTabContent);
OnPropertyChanged("TabContentList");
SelectedTabItem = currentTabContent;
}
private TabContent selectedTabItem = null;
private ObservableCollection<TabContent> tabContentList = null;
private ICommand loadTabCommand = null;
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
}
Code for TabContentTemplateSelector.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Controls;
using System.Windows;
namespace TabControlTestApp
{
class TabContentTemplateSelector : DataTemplateSelector
{
public override System.Windows.DataTemplate SelectTemplate(object item, System.Windows.DependencyObject container)
{
FrameworkElement element = container as FrameworkElement;
if (element != null && item != null)
{
TabContent tabContent = (TabContent)item;
if (tabContent.ShowSecondPanel)
{
return element.FindResource("TabContentWithBothPanel") as DataTemplate;
}
else
{
return element.FindResource("TabContentWithFirstPanel") as DataTemplate;
}
}
else
{
return base.SelectTemplate(item, container);
}
}
}
}
Code for TabContent Data Object
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace TabControlTestApp
{
class TabFirstPanel
{
public string Name { get; set; }
public string Age { get; set; }
}
class TabSecondPanel
{
public string AdditionalDetails { get; set; }
}
class TabContent
{
public TabFirstPanel TabFirstPanel { get; set; }
public TabSecondPanel TabSecondPanel { get; set; }
public bool ShowSecondPanel { get; set; }
}
}
Code for LoadTabCommand Class
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Input;
namespace TabControlTestApp
{
class LoadTabCommand : ICommand
{
MainWindowViewModel mainWindowViewModel = null;
public LoadTabCommand(MainWindowViewModel mainWindowViewModel)
{
this.mainWindowViewModel = mainWindowViewModel;
}
public bool CanExecute(object parameter)
{
return true;
}
public event EventHandler CanExecuteChanged;
public void Execute(object parameter)
{
System.Windows.Controls.Button btn = (System.Windows.Controls.Button)parameter;
switch (btn.Name)
{
case "LoadTab1":
mainWindowViewModel.LoadFirstTab();
break;
case "LoadTab2":
mainWindowViewModel.LoadSecondTab();
break;
case "LoadTab3":
mainWindowViewModel.LoadThirdTab();
break;
case "ShowHideSecondPanelInTab":
mainWindowViewModel.ShowHideSecondPanelInTab();
break;
}
}
}
}

I took a look at your example. Thanks for posting code. Now I understand your issue completely. Before I suggested to change DynamicResource to StaticResource I thought you wanted to only look up once for your DataTemplate.
Now I see you wish to keep the instance of DataTemplate alive so TabControl doesn't destroy it when changing tabs.
Here is the solution:
<Window.DataContext>
<local:MainWindowViewModel />
</Window.DataContext>
<Window.Resources>
<local:TabContentTemplateSelector x:Key="tabContentTemplateSelector" />
<DataTemplate x:Key="TabitemDataTemplate">
<StackPanel Width="50" Height="50">
<TextBlock Text="{Binding TabFirstPanel.Name}"></TextBlock>
</StackPanel>
</DataTemplate>
<Grid x:Key="template1">
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0">Name :</TextBlock>
<TextBlock Grid.Row="0" Grid.Column="1" Text="{Binding TabFirstPanel.Name}"></TextBlock>
</Grid>
<Grid x:Key="template2">
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200"></ColumnDefinition>
<ColumnDefinition Width="5"></ColumnDefinition>
<ColumnDefinition Width="Auto"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid Grid.Row="0" Grid.Column="0">
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0">Name :</TextBlock>
<TextBlock Grid.Row="0" Grid.Column="1" Text="{Binding TabFirstPanel.Name}"></TextBlock>
</Grid>
<GridSplitter Grid.Row="0" Grid.Column="1"
VerticalAlignment="Stretch"
Width="5"
Height="Auto"
ResizeDirection="Columns"
ResizeBehavior="PreviousAndNext"/>
<Grid Grid.Row="0" Grid.Column="2">
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0">Additional Detail :</TextBlock>
<TextBlock Grid.Row="0" Grid.Column="1" Text="{Binding TabSecondPanel.AdditionalDetails}"></TextBlock>
</Grid>
</Grid>
<DataTemplate x:Key="TabContentWithFirstPanel">
<ContentPresenter Content="{StaticResource template1}"/>
</DataTemplate>
<DataTemplate x:Key="TabContentWithBothPanel">
<ContentPresenter Content="{StaticResource template2}"/>
</DataTemplate>
If you just copy past that you will do fine.
By the way, just as sidenote for you, destroying and building up DataTemplates is very important in wpf for releasing unmanaged memory.

I don't believe you may avoid this behavior, unless you use another control other than the TabControl.
The TabControl is a ItemControl-derived component: if its content is created via DataTemplate (as you done), the actual content is generated every time upon the current selection.
Another option is to fill the TabControl with direct content, and the inner controls should be preserved across the selection.
Have a look here:
http://msdn.microsoft.com/en-us/library/system.windows.controls.tabcontrol(v=vs.110).aspx
UPDATE: First off, I am not sure to have understand what you want, but here is a solution based on what I mean.
The fundamental trick is hosting directly the tab-contents, instead of creating via data-templating. That is:
<TabControl>
<TabItem Header="Tab1">
<TextBlock
Text="Page 1"
HorizontalAlignment="Center"
VerticalAlignment="Center"
/>
</TabItem>
<TabItem Header="Tab2">
<CheckBox
Content="check me"
HorizontalAlignment="Center"
VerticalAlignment="Center"
/>
</TabItem>
<TabItem Header="Tab3">
<TextBlock
Text="Page 3"
HorizontalAlignment="Center"
VerticalAlignment="Center"
/>
</TabItem>
</TabControl>
The above snippet should "persist" the checkbox value across the tabs flipping.
But you need (or desire) some kind of templating, or a dynamic way to create the right content upon a certain data added to the tabcontrol.
The following trick should solve your problem:
<TabControl>
<TabItem
Header="Tab1"
>
<ContentControl
Content="{Binding Path=A}"
ContentTemplateSelector="{StaticResource sel}"
/>
</TabItem>
<TabItem
Header="Tab2"
>
<ContentControl
Content="{Binding Path=B}"
ContentTemplateSelector="{StaticResource sel}"
/>
</TabItem>
<TabItem
Header="Tab3"
>
<ContentControl
Content="{Binding Path=C}"
ContentTemplateSelector="{StaticResource sel}"
/>
</TabItem>
</TabControl>
This is using a trivial set of templates as follows:
<Window.Resources>
<local:MySelector x:Key="sel" />
<DataTemplate x:Key="dtplA">
<StackPanel Margin="30,30">
<TextBlock Text="A: " />
<TextBox />
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="dtplB">
<StackPanel Margin="30,30">
<TextBlock Text="B: " />
<TextBox />
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="dtplC">
<StackPanel Margin="30,30">
<TextBlock Text="C: " />
<TextBox />
</StackPanel>
</DataTemplate>
</Window.Resources>
And the behind-code is even more trivial:
public class VM
{
public A A { get; set; }
public B B { get; set; }
public C C { get; set; }
}
public class A { }
public class B { }
public class C { }
public class MySelector : DataTemplateSelector
{
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
if (item != null)
{
return (DataTemplate)((FrameworkElement)container).FindResource("dtpl" + item.GetType().Name);
}
else
{
return base.SelectTemplate(item, container);
}
}
}
If you try this small example, the text typed into the textboxes will persist across the tabs flipping. That is, the templates will be called once only.
Let me know.