Keydown event when the form is not active - c#

How can I capture the Keydown event of a form that is not active?
I found references to ProcessKeyDown but I couldn't find any help on that.

Please set KeyPreview of the form to true. First select form and press f4 key, it will open property window and their is KeyPreview and set it to true.

Right cilck on the form and cilck properties, then there will be flash button , it is for events for that object. Find thier Keypress event. just doulbe click on the column corresponding to that event. It will create event for keypress.
For the documentation and help, check this link.

Keypress events are only sent to Controls that have input focus. You can use the Control.HasFocus property to determine whether your Control has focus or not. Use the Control.Focus() method to give your control focus.

You can set a low level keyboard hook using SetWindowsHookEx() to listen for key press events.

If what you want to do is trigger some code in your program upon keys being pressed in the operating system regarding of whether the form is active or not then you can use the method described in this article:
Processing Global Mouse and Keyboard Hooks in C#
Here is a simple example of a program using that library to simulate a virtual mouse by pressing the numeric keys on the numpad.
'1'-'4' and '6'-'9' are directional keys, '5' is left click, '0' is double click.
Program.cs
Form1.cs
Observe that i didn't call the Application.Run(); with a new Form1() parameter so that the application would run but will not be visible on screen. To end the program you have to press CTRL+SHIFT+ESC, go to Processes page and end the process manually.

Related

How to change button click event into enter event?

I'm new on C#, I made a button which makes appear another button and I want to remove the click event of this new one and change it into an enter(key) event.
Code1
Code2
When the button appears it only works when I click it but no when I press Enter.
As to your question, https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.control.enter?view=net-5.0
The enter event is for when keyboard or mouse enter the control (button in this case).
From the sounds of your question, you are wanting to click the button when the 'Enter' key is pressed.
If this is WinForms, then you might actually want a property on the parent form called 'AcceptButton' (https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.form.acceptbutton?view=net-5.0). This will make it so anytime the Enter key is hit (with the exception of controls such as a RichTextBox that accepts the return key) that button will be clicked (course you still need the button click event for the button).
Although you seem to be doing something weird in your example code image, so I'm not sure that's the correct solution for it. Instead, you need to look at maybe the Keyboard events, such as KeyPress (https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.control.keypress?view=net-5.0). There are several: KeyDown, KeyPress, KeyUp, and PreviewKeyDown.
Note these events require Keyboard focus on the control in question. So if add them to the button you are creating in your example code, then that button will need keyboard focus to receive the keyboard events.
Also, just FYI, if a button has keyboard focus, by default the SpaceBar will click that button for you, while the Enter key is generally reserved for clicking the Form's AcceptButton.

How to register pressing F2 on the MC75a in C#?

I'm trying to register a button press of the button F2 on the MC75a hand held terminal by Motorola/Zebra/Symbol. But it doesn't recognise the blue button press which is required to press F2. Any suggestions?
It depends on what is on your form. So if you have a windows form-project and a textbox is focused you could handle the keypress event of this control. If you have no focused controls, set your form to "keypreview = true". You can find this option in the settings of the form editor.
After enabling keypreview you can handle the keypress event from the form. This should work.
If you already enabled keypreview and it does not work, please make a test-form where you can see the keycodes which are send. There is a possibility to remap the keyboard of motorola devices.

How to read keyboard input, KeyChar, on FormLoad event in C#?

A key is pressed while starting up a winform program. I'd like to read this keyboard input during program startup process. How can I do that?
Set KeyPreview of your Form to True and add your code in form's KeyPress or KeyDown event.

In Gtk, can I make a Button's mnemonic not require an "alt" mask?

I have 6 Buttons, labeled "_0" through "_5". I would like for each button to be pressed when the user presses the corresponding number key. Right now, they must press Alt + the corresponding number key.
I can sort of work around this by giving each button an Accelerator, but it's not quite the same thing. With accelerators, as soon as the key is pressed, the button's Clicked signal is triggered. With mnemonics, the button becomes depressed when the key is pressed, and the Clicked signal isn't triggered until the button is released. I prefer this, because it helps the user to see what is happening.
Is there any way I can get the behavior of Mnemonics, but without requiring the Alt key?
You can have the gtk window catch key events with the event mask settings in the window class. I can't be much more specific than that with callbacks and key types, because I use GTKmm (C++ bindings) but the approach should be similar. Basically when you catch the required key event in your window you can call the button press in code. The window has be to selected (in focus) however.

Use right-click with Windows Forms Button

I am writing an app where the user should be able to alter the action of a button.
The user should right-click a button, and choose an option from a pop-up context menu. Once the choice has been made the button will perform a different action when the user uses a normal click.
I've already gotten the "Click" event working for a normal button click, however the "MouseClick" event handler isn't working correctly.
The "MouseClick" event gets activated on regular left-clicks, but never get's called for right-click.
Is there some default event handling being performed that is ignoring that right-click?
I'm sorry to say that this would be a serious UI blooper. Perhaps it would make more sense to add a small combobox next to the button.
Perhaps something like this?
http://www.codeproject.com/KB/buttons/SplitButton.aspx
If you want to display a context menu with actions to choose from it should be enough to assign a ContextMenuStrip to the ContextMenuStrip property. There is usually no need to manually handle the mouse events for that.
surely it would be better to implement it on the MouseDown event rather than the MouseUp event. i dont understand how this is much different from MouseClick event
edit: Just tried this and it works a treat :)
In Button (and certain other controls), the MouseClick event is only fired for the left button. Refer to MSDN.
If you want to know about the right button, respond to the MouseUp event--though as other posters have pointed out, this isn't a great UI idiom.
Use the Mouse UP event... test that Button.X and Button.Y are within the size of the button otherwise you have moved the mouse away from the button.
Terry G

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