UWP C# On Key down not working properly.

Question

UWP C# On Key down not working properly.

VoyTec 671

I am wondering why action "OnKeyDown" is not working properly.
When I use this class the calculations of my program goes wierd with "NaN" besides a concrete number.
How to make any key down calculate price?

Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-21T07:37:23.803+00:00

Do you make custom control and OnKeyDown OnKeyDown visual method ?
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-21T07:41:00.687+00:00

Could you mind share your code that you have used for listen OnKeyDown action?

VoyTec 671

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)

private void KeyDown(object sender, Windows.UI.Xaml.Input.KeyRoutedEventArgs e)  
        {  
            calculate();  
        }  
  
private void calculate()  
        {  
            to_square_meter = price_square_meter.Value;  
            zero_three = (width.Value * height.Value) / 1000000;  
            cprice_net.Value = price_net.Value * quantity.Value;  
            var price_net_value_change = price_net.Value;  
            price_net.Text = String.Format("{0:0.00}", price_net_value_change);  
            gross calculation = price_net.Value * 1.23;  
            price_gross_text.Text = "GROSS price:     " + String.Format("{0:0.00}", gross_calculation) + "euro";  
         }

Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-23T01:23:07.37+00:00

During the testing, if the control has been focused, KeyDown will be invoked, please check if it was focused before press keyboard.
VoyTec 671 Reputation points

2021-06-23T04:14:24.423+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Can you elaborate? I am a beginner, what do you mean by that?
VoyTec 671 Reputation points

2021-06-23T04:34:14.977+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Do you mean System.Boolean IsFocusedEngaged?
It can't be triggered, even if I trigger it my app crashes.
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-23T06:28:08.627+00:00

Ok, could tell which control KeyDown event that you want listen? could you share your xaml code ?
VoyTec 671 Reputation points

2021-06-23T06:35:15.267+00:00
@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)

<muxc:NumberBox x:Name="height" HorizontalAlignment="Left" Margin="6,163,0,0" VerticalAlignment="Top" Width="76" Foreground="#FF200493" ValueChanged="height_vc" Grid.Row="2" Grid.Column="1" KeyDown="test"/>

not much to be honest, should I have something there?
If I check "IsFocusEngaged" it deslects back but it puts code inside xaml object, andy my app crashes with it.
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-23T06:44:15.713+00:00

KeyDown="test" could be triggered when the cursor flash in the box.
VoyTec 671 Reputation points

2021-06-23T06:49:48.18+00:00

no, my cursor hoover over the box when typing and still not working... :/
@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-23T07:14:52.24+00:00

That's interesting, can you make blank sample test it, I'm afraid other control has handled this event.
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-23T09:53:04.127+00:00

could you mind share a sample that could reproduce this problem ?
VoyTec 671 Reputation points

2021-06-23T20:22:26.117+00:00

Thank you fore help so far.
I ma istalling VS 2022P maybe that will work on it...
@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-24T01:21:50.94+00:00

Ok. please let me know the test result.
VoyTec 671 Reputation points

2021-06-24T14:35:22.257+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
It didn\t solve my problem.
When I will have more of free time I will share my code with you.
thanks!
VoyTec 671 Reputation points

2021-06-24T19:48:35.833+00:00

My project is on GitHub now. I need your nickname to make you a collaborator cause I made it private.
@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-25T01:48:18.327+00:00

Due to our policy, it is not suitable to make a forum support a collaborator of your private project.
We don't want to check your whole project because it might contain your private information. What we need is just a minimal, reproducible example. Please create a blank project. Then just add the necessary code which is used to reproduce the issue inside the project. Then you could share the sample in public with us.
VoyTec 671 Reputation points

2021-06-25T18:07:34.797+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
I don't know how i managed to make UI.Xaml Nuget for NumbeBox working in my original project, cause I made new project to show you the error and my number box won't show at all now... :/
VoyTec 671 Reputation points

2021-06-27T20:05:08.55+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
I figured out another way to do my program.
Can you show me how to make periodic event - every 1 second do something?
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-30T02:50:00.277+00:00
Can you show me how to make periodic event - every 1 second do something?

Sure, you could use DispatcherTimer to approach, here is sample code.

dispatcherTimer = new DispatcherTimer(); dispatcherTimer.Tick += dispatcherTimer_Tick; dispatcherTimer.Interval = new TimeSpan(0, 0, 1);

For more please refer official document.
VoyTec 671 Reputation points

2021-06-30T18:54:15.767+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
My project doesn't recognize "Threading" and "dispatcherTimer".
I used System.Threading and System.Timers and it didn't help.
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-07-01T02:03:34.893+00:00

It's my fault, I have updated the document, please use DispatcherTimer under Windows.UI.Xaml namespace.
VoyTec 671 Reputation points

2021-07-01T12:08:57.1+00:00

Thanks @Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
I will check it out as soon as I return home.
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-07-09T02:16:53.883+00:00

Does it works, Any updates for this topic.
VoyTec 671 Reputation points

2021-08-23T19:20:17.663+00:00
OK @Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Back to the problem.
I thought with 2022 or Win11 would fix the issues but it didn't.

Key down still not working: I have keydown event but it works after few click and not for the first time and mostly for ENTER.

Dispatcher needs some libraries (namespaces) cause it doesnt recognize the code, can you share it with me?
Thanks

Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-21T07:37:23.803+00:00

Do you make custom control and OnKeyDown OnKeyDown visual method ?
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-21T07:41:00.687+00:00

Could you mind share your code that you have used for listen OnKeyDown action?
VoyTec 671 Reputation points

2021-06-22T23:40:24.617+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)

private void KeyDown(object sender, Windows.UI.Xaml.Input.KeyRoutedEventArgs e) { calculate(); } private void calculate() { to_square_meter = price_square_meter.Value; zero_three = (width.Value * height.Value) / 1000000; cprice_net.Value = price_net.Value * quantity.Value; var price_net_value_change = price_net.Value; price_net.Text = String.Format("{0:0.00}", price_net_value_change); gross calculation = price_net.Value * 1.23; price_gross_text.Text = "GROSS price: " + String.Format("{0:0.00}", gross_calculation) + "euro"; }
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-23T01:23:07.37+00:00

During the testing, if the control has been focused, KeyDown will be invoked, please check if it was focused before press keyboard.
VoyTec 671 Reputation points

2021-06-23T04:14:24.423+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Can you elaborate? I am a beginner, what do you mean by that?
VoyTec 671 Reputation points

2021-06-23T04:34:14.977+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Do you mean System.Boolean IsFocusedEngaged?
It can't be triggered, even if I trigger it my app crashes.
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-23T06:28:08.627+00:00

Ok, could tell which control KeyDown event that you want listen? could you share your xaml code ?
VoyTec 671 Reputation points

2021-06-23T06:35:15.267+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)

<muxc:NumberBox x:Name="height" HorizontalAlignment="Left" Margin="6,163,0,0" VerticalAlignment="Top" Width="76" Foreground="#FF200493" ValueChanged="height_vc" Grid.Row="2" Grid.Column="1" KeyDown="test"/>

not much to be honest, should I have something there?
If I check "IsFocusEngaged" it deslects back but it puts code inside xaml object, andy my app crashes with it.
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-23T06:44:15.713+00:00

KeyDown="test" could be triggered when the cursor flash in the box.
VoyTec 671 Reputation points

2021-06-23T06:49:48.18+00:00

no, my cursor hoover over the box when typing and still not working... :/
@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-23T07:14:52.24+00:00

That's interesting, can you make blank sample test it, I'm afraid other control has handled this event.
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-23T09:53:04.127+00:00

could you mind share a sample that could reproduce this problem ?
VoyTec 671 Reputation points

2021-06-23T20:22:26.117+00:00

Thank you fore help so far.
I ma istalling VS 2022P maybe that will work on it...
@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-24T01:21:50.94+00:00

Ok. please let me know the test result.
VoyTec 671 Reputation points

2021-06-24T14:35:22.257+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
It didn\t solve my problem.
When I will have more of free time I will share my code with you.
thanks!
VoyTec 671 Reputation points

2021-06-24T19:48:35.833+00:00

My project is on GitHub now. I need your nickname to make you a collaborator cause I made it private.
@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-25T01:48:18.327+00:00

Due to our policy, it is not suitable to make a forum support a collaborator of your private project.
We don't want to check your whole project because it might contain your private information. What we need is just a minimal, reproducible example. Please create a blank project. Then just add the necessary code which is used to reproduce the issue inside the project. Then you could share the sample in public with us.
VoyTec 671 Reputation points

2021-06-25T18:07:34.797+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
I don't know how i managed to make UI.Xaml Nuget for NumbeBox working in my original project, cause I made new project to show you the error and my number box won't show at all now... :/
VoyTec 671 Reputation points

2021-06-27T20:05:08.55+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
I figured out another way to do my program.
Can you show me how to make periodic event - every 1 second do something?
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-06-30T02:50:00.277+00:00

Can you show me how to make periodic event - every 1 second do something?

Sure, you could use DispatcherTimer to approach, here is sample code.

dispatcherTimer = new DispatcherTimer(); dispatcherTimer.Tick += dispatcherTimer_Tick; dispatcherTimer.Interval = new TimeSpan(0, 0, 1);

For more please refer official document.
VoyTec 671 Reputation points

2021-06-30T18:54:15.767+00:00

@Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
My project doesn't recognize "Threading" and "dispatcherTimer".
I used System.Threading and System.Timers and it didn't help.
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-07-01T02:03:34.893+00:00

It's my fault, I have updated the document, please use DispatcherTimer under Windows.UI.Xaml namespace.
VoyTec 671 Reputation points

2021-07-01T12:08:57.1+00:00

Thanks @Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
I will check it out as soon as I return home.
Nico Zhu (Shanghai Wicresoft Co,.Ltd.) 12,826 Reputation points

2021-07-09T02:16:53.883+00:00

Does it works, Any updates for this topic.
VoyTec 671 Reputation points

2021-08-23T19:20:17.663+00:00

OK @Nico Zhu (Shanghai Wicresoft Co,.Ltd.)
Back to the problem.
I thought with 2022 or Win11 would fix the issues but it didn't.

Key down still not working: I have keydown event but it works after few click and not for the first time and mostly for ENTER.

Dispatcher needs some libraries (namespaces) cause it doesnt recognize the code, can you share it with me?
Thanks

Answer 1

VoyTec 671

I was missing namespace - I cleaned up my code and it removed Input asset - that's why it didn't work.

UWP C# On Key down not working properly.

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