TreeView.Expanding Event

Definition

Namespace:

Windows.UI.Xaml.Controls

Occurs when a node in the tree starts to expand.

Equivalent WinUI 2 API for UWP: Microsoft.UI.Xaml.Controls.TreeView.Expanding (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).

// Register
event_token Expanding(TypedEventHandler<TreeView, TreeViewExpandingEventArgs const&> const& handler) const;

// Revoke with event_token
void Expanding(event_token const* cookie) const;

// Revoke with event_revoker
TreeView::Expanding_revoker Expanding(auto_revoke_t, TypedEventHandler<TreeView, TreeViewExpandingEventArgs const&> const& handler) const;

public event TypedEventHandler<TreeView,TreeViewExpandingEventArgs> Expanding;

function onExpanding(eventArgs) { /* Your code */ }
treeView.addEventListener("expanding", onExpanding);
treeView.removeEventListener("expanding", onExpanding);
- or -
treeView.onexpanding = onExpanding;

Public Custom Event Expanding As TypedEventHandler(Of TreeView, TreeViewExpandingEventArgs) 

Event Type

TypedEventHandler<TreeView,TreeViewExpandingEventArgs>