Is there Selected Tab Changed Event in the standard WPF Tab Control - wpf

Question

In WPF, is there an event that can be used to determine when a TabControl's selected tab changes?
I have tried using TabControl.SelectionChanged but it is getting fired many times when a child's selection within a tab is changed.

Answer 1

I tied this in the handler to make it work:
void TabControl_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e.Source is TabControl)
{
//do work when tab is changed
}
}

Answer 2

If you set the x:Name property to each TabItem as:
<TabControl x:Name="MyTab" SelectionChanged="TabControl_SelectionChanged">
<TabItem x:Name="MyTabItem1" Header="One"/>
<TabItem x:Name="MyTabItem2" Header="2"/>
<TabItem x:Name="MyTabItem3" Header="Three"/>
</TabControl>
Then you can access to each TabItem at the event:
private void TabControl_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (MyTabItem1.IsSelected)
// do your stuff
if (MyTabItem2.IsSelected)
// do your stuff
if (MyTabItem3.IsSelected)
// do your stuff
}

Answer 3

If you just want to have an event when a tab is selected, this is the correct way:
<TabControl>
<TabItem Selector.Selected="OnTabSelected" />
<TabItem Selector.Selected="OnTabSelected" />
<TabItem Selector.Selected="OnTabSelected" />
<!-- You can also catch the unselected event -->
<TabItem Selector.Unselected="OnTabUnSelected" />
</TabControl>
And in your code
private void OnTabSelected(object sender, RoutedEventArgs e)
{
var tab = sender as TabItem;
if (tab != null)
{
// this tab is selected!
}
}

Answer 4

You could still use that event. Just check that the sender argument is the control you actually care about and if so, run the event code.

Answer 5

If you're using the MVVM pattern then it is inconvenient (and breaks the pattern) to use the event handler. Instead, you can bind each individual TabItem's Selector.IsSelected property to a dependency property in your viewmodel and then handle the PropertyChanged event handler. That way you know exactly which tab was selected/deselected based on the PropertyName and you have a special handler for each tab.
Example: MainView.xaml
<TabControl>
<TabItem Header="My tab 1" Selector.IsSelected="{Binding IsMyTab1Selected}"> ... </TabItem>
<TabItem Header="My tab 2" Selector.IsSelected="{Binding IsMyTab2Selected}"> ... </TabItem>
</TabControl>
Example: MainViewModel.cs
public bool IsMyTab1Selected {
get { return (bool)GetValue(IsMyTab1SelectedProperty); }
set { SetValue(IsMyTab1SelectedProperty, value); }
}
public static readonly DependencyProperty IsMyTab1SelectedProperty =
DependencyProperty.Register("IsMyTab1Selected", typeof(bool), typeof(MainViewModel), new PropertyMetadata(true, new PropertyChangedCallback(MyPropertyChanged)));
public bool IsMyTab2Selected {
get { return (bool)GetValue(IsMyTab2SelectedProperty); }
set { SetValue(IsMyTab2SelectedProperty, value); }
}
public static readonly DependencyProperty IsMyTab2SelectedProperty =
DependencyProperty.Register("IsMyTab2Selected", typeof(bool), typeof(MainViewModel), new PropertyMetadata(false, new PropertyChangedCallback(MyPropertyChanged)));
private void MyPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
if (e.Property.Name == "IsMyTab1Selected") {
// stuff to do
} else if (e.Property.Name == "IsMyTab2Selected") {
// stuff to do
}
}
If your MainViewModel is INotifyPropertyChanged rather than DependencyObject, then use this instead:
Example: MainViewModel.cs
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName) {
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
public MainViewModel() {
PropertyChanged += handlePropertyChanged;
}
public bool IsMyTab1Selected {
get { return _IsMyTab1Selected ; }
set {
if (value != _IsMyTab1Selected ) {
_IsMyTab1Selected = value;
OnPropertyChanged("IsMyTab1Selected ");
}
}
}
private bool _IsMyTab1Selected = false;
public bool IsMyTab2Selected {
get { return _IsMyTab2Selected ; }
set {
if (value != _IsMyTab2Selected ) {
_IsMyTab2Selected = value;
OnPropertyChanged("IsMyTab2Selected ");
}
}
}
private bool _IsMyTab2Selected = false;
private void handlePropertyChanged(object sender, PropertyChangedEventArgs e) {
if (e.PropertyName == "IsMyTab1Selected") {
// stuff to do
} else if (e.PropertyName == "IsMyTab2Selected") {
// stuff to do
}
}

Answer 6

The event generated is bubbling up until it is handled.
This xaml portion below triggers ui_Tab_Changed after ui_A_Changed when the item selected in the ListView changes, regardless of TabItem change in the TabControl.
<TabControl SelectionChanged="ui_Tab_Changed">
<TabItem>
<ListView SelectionChanged="ui_A_Changed" />
</TabItem>
<TabItem>
<ListView SelectionChanged="ui_B_Changed" />
</TabItem>
</TabControl>
We need to consume the event in ui_A_Changed (and ui_B_Changed, and so on):
private void ui_A_Changed(object sender, SelectionChangedEventArgs e) {
// do what you need to do
...
// then consume the event
e.Handled = true;
}

Answer 7

That is the correct event. Maybe it's not wired up correctly?
<TabControl SelectionChanged="TabControl_SelectionChanged">
<TabItem Header="One"/>
<TabItem Header="2"/>
<TabItem Header="Three"/>
</TabControl>
in the codebehind....
private void TabControl_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
int i = 34;
}
if I set a breakpoint on the i = 34 line, it ONLY breaks when i change tabs, even when the tabs have child elements and one of them is selected.

Answer 8

This code seems to work:
private void TabControl_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
TabItem selectedTab = e.AddedItems[0] as TabItem; // Gets selected tab
if (selectedTab.Name == "Tab1")
{
// Do work Tab1
}
else if (selectedTab.Name == "Tab2")
{
// Do work Tab2
}
}

Answer 9

If anyone use WPF Modern UI,they cant use OnTabSelected event.but they can use SelectedSourceChanged event.
like this
<mui:ModernTab Layout="Tab" SelectedSourceChanged="ModernTab_SelectedSourceChanged" Background="Blue" AllowDrop="True" Name="tabcontroller" >
C# code is
private void ModernTab_SelectedSourceChanged(object sender, SourceEventArgs e)
{
var links = ((ModernTab)sender).Links;
var link = this.tabcontroller.Links.FirstOrDefault(l => l.Source == e.Source);
if (link != null) {
var index = this.tabcontroller.Links.IndexOf(link);
MessageBox.Show(index.ToString());
}
}