TreeViewControl.GetActiveEditorNeedsKey Event

Allows you to specify whether the active editor responds to certain keystrokes.

Namespace: DevExpress.Xpf.Grid

Assembly: DevExpress.Xpf.Grid.v26.1.dll

Declaration

C#

public event EventHandler<TreeViewGetActiveEditorNeedsKeyEventArgs> GetActiveEditorNeedsKey

VB.NET

Public Event GetActiveEditorNeedsKey As EventHandler(Of TreeViewGetActiveEditorNeedsKeyEventArgs)

Event Data

The GetActiveEditorNeedsKey event's data class is TreeViewGetActiveEditorNeedsKeyEventArgs. The following properties provide information specific to this event:

Property	Description
Column	Gets the column that contains the active editor cell.
Handled	Gets or sets a value that indicates the present state of the event handling for a routed event as it travels the route. Inherited from RoutedEventArgs.
Key	Gets the key a user pressed to activate the editor.
Modifiers	Gets the modifier keys (Shift, Ctrl, and Alt) a user pressed to activate the editor.
NeedsKey	Gets or sets if the active editor processes the current keystroke.
OriginalSource	Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs.
RoutedEvent	Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs.
RowHandle	Gets the handle of the row that contains the active editor cell.
Source	Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs.
TemplateChild	Gets an in-place editor specified in a cell template.
Value	Gets the current value in the active editor.

The event data class exposes the following methods:

Method	Description
InvokeEventHandler(Delegate, Object)	When overridden in a derived class, provides a way to invoke event handlers in a type-specific way, which can increase efficiency over the base implementation. Inherited from RoutedEventArgs.
OnSetSource(Object)	When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes. Inherited from RoutedEventArgs.

Remarks

Handle the GetActiveEditorNeedsKey event to prevent key conflicts between navigation keystrokes in the TreeViewControl and the active in-place editor. You can set the e.NeedsKey property to false within a GetActiveEditorNeedsKey event handler to prevent the current keystroke from being processed by the in-place editor.

Example: Enable Arrow Keys for an In-Place Editor

The following example allows a ListBoxEdit in-place editor to process Up and Down keystrokes:

XAML

<dx:ThemedWindow x:Class="TreeViewControlApp.MainWindow"
                 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                 xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
                 xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid"
                 Title="TreeViewControl Demo" Height="450" Width="600">
    <dxg:TreeViewControl x:Name="tree"
                         ChildNodesPath="Employees"
                         TreeViewFieldName="Name"
                         GetActiveEditorNeedsKey="OnGetActiveEditorNeedsKey">
            <dxg:TreeViewControl.EditSettings>
                <dxe:ListBoxEditSettings ItemsSource="{Binding Items}" />
            </dxg:TreeViewControl.EditSettings>
    </dxg:TreeViewControl>
</dx:ThemedWindow>

C#

private void OnGetActiveEditorNeedsKey(object sender, TreeViewGetActiveEditorNeedsKeyEventArgs e) {
    if (e.Key == System.Windows.Input.Key.Up || e.Key == System.Windows.Input.Key.Down)
        e.NeedsKey = true;
}

Related Events

The TreeViewControl fires the following events to process user actions that activate an in-place editor:

GetIsEditorActivationAction

Allows you to specify an action (key down, text input, or left mouse button click) to activate the focused editor.

ProcessEditorActivationAction

Allows you to specify whether the focused node should process an editor activation action.