Need ability to exit Alt key underline mode, possibly with ESC key - wpf

Question

Question: How do you exit keyboard hot-key mode after pressing and releasing the Alt key? In Office the ESC works, in WPF it does not.
Details: I have various Label elements in a WPF application.
<StackPanel>
<Label Grid.Column="0" VerticalAlignment="Center" Content="_Textbox 1" Target="textbox1" />
<TextBox x:Name="textbox1" Width="50" />
<Label Grid.Column="0" VerticalAlignment="Center" Content="T_extbox 2" Target="textbox2" />
<TextBox x:Name="textbox2" Width="50" />
</StackPanel>
When I press and release the Alt key the P stays underlined and I can then separately press the P key and that Label takes its action. This is the same as how Word 2013 and Notepad work in that you don't have to press the Alt and the P at the same time.
Where WPF differs is I cannot press the ESC key to stop the underlining and stop the auto-navigation to Label controls. The only way I see to get out of keyboard navigation mode is to use the mouse and click somewhere, defeating the goal of keyboard navigation.

Answer 1

Adding to my original comment
Actually there is a slight difference in Notepad and Word 2013 behavior. The control's there with the hot-key are in a Menu which takes Focus as soon as you press Alt and you can see they get focus cos the text area caret goes missing and Esc then returns focus to the TextBox while clearing the "_". Now in your sample code if you put the two Label's or even one inside a and then press Alt, you get the same behavior as Word or Notepad. Without the Menu there is no control that wants to take the intermediate focus.
This just seems to be an issue where the Menu gets a deferred focus to handle these hotkeys in it's own FocusManager.IsFocusScope.
Another snippet from MSDN:
The following scenario illustrates how keyboard focus and logical focus change in a Windows Presentation Foundation (WPF) application that has a Window with a TextBox and a Menu which has a MenuItem. When keyboard focus changes from the TextBox to the MenuItem, the TextBox losses keyboard focus but retains logical focus for the Window focus scope. The MenuItem obtains keyboard focus and obtains logical focus for the Menu focus scope. When keyboard focus returns to the root Window, the element in Window focus scope with logical focus will obtain keyboard focus, which in this case is the TextBox. The TextBox now has keyboard focus and logical focus. The MenuItem loses keyboard focus, but retains logical focus for the Menu focus scope.
Solution:
If you just can't stand the fact that you're limited with the grouping requirement imposed by the Menu to achieve the hot-key functionality, you could do something like:
<Grid Margin="25">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="15" />
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<!-- cannot use Visibility="Collapsed" or "Hidden" on the Menu to make it take focus on Alt press -->
<Menu Width="0"
Height="0">
<Label x:Name="label1"
Content="_Textbox 1"
Target="{Binding ElementName=textbox1}" />
<Label x:Name="label2"
Content="T_extbox 2"
Target="{Binding ElementName=textbox2}" />
<Label x:Name="label3"
Content="Another Loose Label to Link Text_Box 1"
Target="{Binding ElementName=textbox1}" />
</Menu>
<Label Grid.Row="0"
Grid.Column="0"
Content="{Binding ElementName=label1,
Path=Content}" />
<TextBox x:Name="textbox1"
Grid.Row="0"
Grid.Column="1"
Grid.ColumnSpan="2"
Margin="15 0 0 0"
VerticalAlignment="Center" />
<Label Grid.Row="2"
Grid.Column="0"
Content="{Binding ElementName=label2,
Path=Content}" />
<TextBox x:Name="textbox2"
Grid.Row="2"
Grid.Column="1"
Grid.ColumnSpan="2"
Margin="15 0 0 0"
VerticalAlignment="Center" />
<Rectangle Grid.Row="3"
Grid.RowSpan="2"
Grid.Column="1"
Margin="10"
Fill="Tomato" />
<Label Grid.Row="4"
Grid.Column="2"
Content="{Binding ElementName=label3,
Path=Content}" />
</Grid>
So in this setup we do not use any custom Style's for any of the control's. We pretty much create a new top level Menu and add all the desired hot-key Label's to it and set it's Width and Height to 0.
Thus in the actual Visible Grid layout we can position the visible Label's anywhere we choose and to avoid code duplication in specifying the Label.Content twice for each Label(Once in the Menu and next in actual layout) we use a Binding to get the Content for the Visual Label from it's corresponding Label in the Menu.
Update
Reply to OP's comment:
I'm not sure this will be practical in my application. I have hotkeys all over the app with some being duplicates inter-screen. It wouldn't be maintainable to implement this type of workaround.
Well I don't see how duplicates or having stuff all over makes any difference to this tbh.
If you have duplicate hot-key's in multiple Window's, then define Content for these duplicate item's as a String resource in xaml or your .resx you can refer to it everywhere you need it.
Maintainable - Well you do not have anything you do special for maintainability. Your layout is not impacted, your not restricted with anything. If anything you got one <Menu> sitting hidden at the Top level of each of your Window's that defines the hot-keys for that Window and within that Window any control that wants that functionality Binds to the corresponding Menu child item. I think it unifies the scope of hot-keys in a Window to a single place than in multiple different places.
Finally, I ain't trying to impose this approach on you, it's boils down to your personal preference. If your uncomfortable with it then you could get your Label's sub-classed and implement the functionality of deferred focus yourself or raise a Microsoft bug to see if they can maybe address it for you or find an alternate solution or let go of the hot-key functionality all-together.