Focus into AutoCompleteBox on CTRL+ N key pressed in UserControl

Question

I want to focus into AutocompleteBox when CTRL+N keys pressed. I've try some code but didn't works for me. In UserControl control, i've used PreviewKeyDown event as below,

Note: i gets focused using below code only when write MessageBox.Show("some"); before key event as below,

private void UserControl_PreviewKeyDown(object sender, KeyEventArgs e)
            {
if (e.Key == Key.N && (Keyboard.Modifiers & ModifierKeys.Control) == ModifierKeys.Control)
            {
MessageBox.Show("sfsd");
                Keyboard.Focus(SearchTextBox);
                SearchTextBox.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
                e.Handled = true;
            }

UserControl:

 <UserControl x:Class="Inventory_Control.UserControls.SaleTab"
                 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:Inventory_Control.UserControls"
                 xmlns:staticData="clr-namespace:Inventory_Control.UserControls"
                 mc:Ignorable="d" 
                 xmlns:controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input.Toolkit"
                 d:DesignHeight="450" d:DesignWidth="800" Loaded="UserControl_Loaded_1" PreviewKeyDown="UserControl_PreviewKeyDown"
                 >

AutoCompleBox:

 <controls:AutoCompleteBox Name="SearchTextBox" IsTextCompletionEnabled="True" SelectedItem="{Binding Code, Mode=TwoWay}" Grid.Column="1" PreviewKeyDown="SearchTextBox_PreviewKeyDown" Grid.Row="1"  >
                    <controls:AutoCompleteBox.ItemTemplate>
                        <DataTemplate>
                            <StackPanel Orientation="Horizontal">
                                <TextBlock Text="{Binding Code}"/>
                                <TextBlock Text="{Binding Name}"/>
                            </StackPanel>
                        </DataTemplate>
                    </controls:AutoCompleteBox.ItemTemplate>
                </controls:AutoCompleteBox>

and capture CTRL+N key event on usercontrol as,

private void UserControl_PreviewKeyDown(object sender, KeyEventArgs e)
        {
if (e.Key == Key.N && (Keyboard.Modifiers & ModifierKeys.Control) == ModifierKeys.Control)
            {
                Keyboard.Focus(SearchTextBox);
                SearchTextBox.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
                e.Handled = true;
            }
}

the above code not works for me.kindly help

Answer 1

You could try to use the dispatcher with a DispatcherPriority lower than Normal :

private void UserControl_PreviewKeyDown(object sender, KeyEventArgs e)
{
    if (e.Key == Key.N && (Keyboard.Modifiers & ModifierKeys.Control) == ModifierKeys.Control)
    {
        Keyboard.Focus(SearchTextBox);
        SearchTextBox.Dispatcher.BeginInvoke(new Action(() =>
        {
            SearchTextBox.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
        }), System.Windows.Threading.DispatcherPriority.Background);
        e.Handled = true;
    }
}