My WPF application is organized as a TabControl with each tab containing a different screen.
One TabItem is bound to data that takes a little while to load. Since this TabItem represents a screen that users may only rarely use, I would like to not load the data until the user selects the tab.
How can I do this?
I found a much simpler way. Simply wait to initialize the ViewModel until the tab is activated.
public int ActiveTab
{
get
{
return _ActiveTab;
}
set
{
_ActiveTab = value;
if (_ActiveTab == 3 && InventoryVM == null) InventoryVM = new InventoryVM();
}
}
A quick and simple Data-centric solution would be to set DataContext by style when the tab IsSelected
<Style TargetType="{x:Type TabItem}">
<Setter Property="DataContext" Value="{x:Null}"/> <!--unset previous dc-->
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="DataContext" Value="{Binding LazyProperty}"/>
</Trigger>
</Style.Triggers>
</Style>
where LazyProperty is a property using some of the lazy load patterns, for example:
private MyVM _lazyProperty;
public MyVM LazyProperty => _lazyProperty ?? (_lazyProperty = new MyVM());