How to hook an event to a windows control in other application - c#

I have to detect when a combobox from an application I have not source code, has changed. The idea is to hook an event to this control, and when the event fires, get the selected value of the control. I have googled but I just have found how to hook with a window (How to hook on a window), when the header text change. I can get the handle of the control (FindWindowEx) but, I have no idea how to hook an event to the control, please guys if any can help me with this.

You can look into the SendMessage API. DDE was an old method of IPC but it still works with .net.
As a cheap easy method, just create a form with a guid + '|' + the handle of a text box as the Text property. When your app runs just load the form but don't show it (hide it from the task tray as well).
Your other app can FindWindowEx on the first apps form using the predetermined guid in the header and also get the handle to the textbox on the form (seperate it from the guid with a pipe char or something).
Now just SendMessage(WM_SETTEXT) to the textbox hwnd (give it the value the user selected in the combobox). If you put an event handler on the text_changed event it will fire in your first app.

Related

Get the input of the Windows emoji-picker

I made my own textbox in UWP, now I want the user to add emojis from the Windows emoji-picker window.
The problem:
When I click any of the emojis with my application focused nothing happens. I check the events that could get triggered by that but non of them got. I also tried it with the ASCII-emojis, but they also don't work.
I checked the CoreWindow_CharacterReceived event and the Paste event, but neither gets fired.
The actual question:
Is there any event I can use to get the input of the emoji-picker or is there a different way?
Github-repo:
https://github.com/FrozenAssassine/TextControlBox-UWP
When I click any of the emojis with my application focused nothing happens.
The problem looks your TextBox is not in focus state, you could focus textbox manually after show Emoji pikcer. Then it will input emoji correctlly.
CoreInputView.GetForCurrentView().TryShow(CoreInputViewKind.Emoji);
YourTextBox.Focus(FocusState.Programmatic);
Update
For customing textbox you could refer to official text editor code sample that implement textbox with CoreTextEditContext.

Changing the Input Language to default when form deactivates

So I have a form, it uses a certain Input Language , when i switch to another window like a browser I want to change back to the computers default Input Language , seems simple. Just use the form deactivate event and put
InputLanguage.CurrentInputLanguage = InputLanguage.DefaultInputLanguage;
Doesn't work. The deactivate event only triggers after the form has been deactivated but the system Input Language cannot be changed unless your form has focus.
I need an event that triggers right before a form deactivates to run that line of code. Anyone have any ideas?

Problems with the KeyPress, KeyDown and KeyUp events in C#

So how to begin.
I am asking when you make a game for example and you add a controlls how do I make the form's key events run when the focus isnt on the form but on some of the controlls and when i call this.Focus() or this.Select() it doesnt't happen anything, but if I use a empty form(with no controls) it works(the events respond).And when i have for example 2 buttons and call button1.focus() and press a key the button1's event handler responds (only it) adn then when i call button2.Focus() it responds for button2.How is focus distributed througt the controlls?
I know for muttons you have to click them once to put the focus on them automaticly and for textboxtes too,but when i click the form it doesnt move the focus on the form.
Im have almost no experience with Key events please explayn me how to use them and how they function understandly.
PS: sorry for the long questin
You can set the Form.KeyPreview to true to have the form react to key events.

Always handle the PreviewKeyDown event in a base form

We need to handle this event in the base form, regardless of which controls currently have focus. We have a couple of global key commands that need to work regardless of control focus.
This works by handling the PreviewKeyDown event in the form normally. When we add a user control to the form, the event no longer fires.
Am I missing something trivial here? Or do we need to handle the event in the user control first?
Thanks for your help!
Thanks Factor. When I get more time :) I'll get it working 'properley'!
The hidden menu you are using works fine for shortcuts that are valid menu item shortcuts, but if you want to use any key as a shortcut (such as Page Up/Page Down), you'll need a different trick.
Another way to do this that doesn't involve P/Invoke is to set the Form.KeyPreview property of your form to true. This will cause all key presses to be sent to the form first, regardless of which control has focus. You can then override OnKeyDown, OnKeyPress, and/or OnKeyUp to handle the key press before any of your controls.
This is probably not the best way of doing it, but the first way that comes to mind.
In your forms constructor, after you call InitializeComponent(); do something like this:
foreach (Control control in this.Controls)
{
control.PreviewKeyDown += new PreviewKeyDownEventHandler(HandlePreviewKeyDown);
}
I THINK that should do the trick. In your HandlePreviewKeyDown method you can then do your work and it should trigger regardless of which control has focus.
PreviewKeyDown only works when the control has focus. It sounds like you should look into an application level hook for a special shortcut keys. You'll have to do it with a P/Invoke. SetWindowsHookEx on pinvoke.net is a good place for an example. Here's a MS KB article about a mouse hook in c#, which appears to be expanded to a keyboard hook in this article.
We ended up doing this:
I found a workaround for this by setting up a hidden menu item by setting:
ToolStripMenuItem.Visible = false
(Thanks to this article).
It appears that the Main Menu of a form always gets searched for your shortcut key combination. This works regardless of whick control has focus

Control.Enter event doesn't fire when switching tasks. Is there an alternative that does?

Rep steps:
create example .NET form application
put a TextBox on the form
wire a function up to the TextBox's Enter event
When you run this application, the Control.Enter event fires when focus first goes to the TextBox. However, if you click away into another application and then click back into the test application, the event will not fire again.
So moving between applications does not trigger Enter/Leave.
Is there another alternative Control-level event that I can use, which will fire in this scenario?
Ordinarily, I would use Form.Activated. Unfortunately, that is troublesome here because my component is hosted by a docking system that can undock my component into a new Form without notifying me.
What are you trying to do in the Enter event?
I can't find another control-level event that fires in your example program but when my test app does regain focus, the control that last had focus still has it.
Interesting question but it needs a little more context.
If I try your example and click outside the control on another window, desktop, etc, I can get the Got and Lost Focus events to fire, but if you're only trying to click within a form or a control with only 1 control, these event will never be fired because it is the only thing to focus on. Neither will Entered or left, unless you change the dynamics or overload the controls, you cannot get this to happen
In your example, I think you need another control. The reason being is that the first control (tabIndex 0) is the one with focus. With no other control to switch focus to, this control will always be focused, and therefore can never be entered. Switching to another application or form will not change the focus or active control in this form so when you return you will still not get the event fired.
With added controls control.entered should work fine. If this is your only control, why not call the event on formLoad, or TextChanged, when the form gets focus?
Thanks, I'll give some background.
My control is a UserControl that contains a grid and a toolbar. A user will typically launch several of these controls to view different slices of the system's data.
There are several keyboards shortcuts that can launch actions from the selected row in the current grid. However, it is a requirement that these keyboard shortcuts should apply not only to the currently focused grid. If the user is currently focused on one of the many other areas of the application, then this keyboard shortcut should still work, and it should be routed to the last focused grid.
So I wired a function to the Control.Enter event of my UserControl to basically say LastFocusedGrid = this.
And it would work, except for the docking and undocking...
See, these controls are hosted inside an application with docking features, somewhat similar to visual studio.
By default, the control launches as a tab within the main working area of the application, similar to the way a source file opens in visual studio.
However, the user can "rip out" a tab by grabbing the tab header and dragging it out of the main application. At this point, the application creates a new "float form" to host the control. Switching between the main application and this float form is the same as switching between apps, for the purposes of the Control.Enter and Form.Activated events.
At that point we have the "one control within a form" scenario simulated with the example application described in the original post.
Now, there are some ways around this. I could leverage the Form.Activated event, which DOES fire when switching between forms. If you add an event in the test application to the Form's Activated event, you will see that it works great.
The problem is that my UserControl's relationship with its parent Form is fluid, making the solution somewhat complicated. I tried wiring up to "this.ParentForm.Activated" which worked okay. The problem is when do you call this? What happens when you are undocked/redocked? I ended up with a nasty bunch of code with things like "previousParentForm" so that I could unhook from the old form, and then I was still facing the problem that the docking system doesn't notify me when my parent Form is being changed, so I was going to have to make a bunch of changes there, too.
These problems are not unsolvable, but if there is a simpler control-level "parent form was activated" event, then that would be a lot more elegant.
That's rather long, but I hope it clarifies the situation.
So when creating your grid, can you not set the KeyPressed, or KeyUp, etc. event? If so, all the grids can make use of the same event handler. Just make sure that when you get into the event handler to do something like:
Grid currentGrid = (Grid)sender;
Then you should be able to apply that block of code to any grid that gets sent in without having to worry about keeping track.
Since all the event handler really is, it's location is a mute point really as long as everything you need to execute it is accessible.
Frye, the problem is that the keyboard shortcuts should work no matter where the user is in the application. They are gloabl commands, handled at the top level, and then routed to the "last focused grid."
So handling the keystrokes at the grid level will not help.
To be more specific, assume user launches grids A, B, and C. But he also launches other controls X, Y, and Z that have nothing to do with my code.
User clicks on A, then on C. Then he clicks on Y, then on Z. With focus on Z, he hits my keyboard shortcut. In this case, grid C should respond since it was the last grid the user was focused in.
It sounds like the issue that you're having is not directly related to the Enter event and more to the point, if you have controls "that have nothing to do with your code" then you really aren't looking at a control level event.
Guess I wasn't clear.
My control lives in a container application. So do other unrelated controls by other teams. Think of it like visual studio -- my control is the code editing tab, but there is also the pending changes list and the properties window, which cohabitate with the source files but aren't directly related.
The keyboard shortcut is handled by the container application. Then it should be routed to the last one of my controls that the user was focused on.
Maintaing this "LastFocusedGrid" reference is what I do in the Enter event.
If you want to see similar functionality at work in visual studio, try this:
open a few source files
navigate to the "Start Page" tab.
Hit Ctrl-F and search "current document" for some string
Notice that the serach feature auto-navigates to the LAST FOCUSED source file to perform the search.
So even though you weren't focused in the source file, the ctrl-F command was processed by visual studio and routed to the last focused source file tab.
Now try the same thing with Ctrl-G. It doesn't work unless you are focused directly in the source file.
My keyboard commands need to work like Ctrl-F here, not like Ctrl-G. That is why I don't just capture the keyboard events directly in my control.
Does that clarify or make things worse?
Have you tried just a simple Control.GotFocus?
in this example if you toggle between clicking the textboxes neither the enter or got focus will do as expected, however if you click the child forms instead both will behave as expected.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
namespace EnterBrokenExample
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Form Form1 = new Form();
Form c1 = new Form();
Form c2 = new Form();
Form1.IsMdiContainer = true;
c1.MdiParent = Form1;
c2.MdiParent = Form1;
c1.Show();
c2.Show();
TextBox tb1 = new TextBox();
c1.Controls.Add(tb1);
tb1.Enter += ontbenter;
tb1.Text = "Some Text";
tb1.GotFocus += ongotfocus;
TextBox tb2 = new TextBox();
c2.Controls.Add(tb2);
tb2.Enter += ontbenter;
tb2.Text = "some other text";
tb2.GotFocus += ongotfocus;
Application.Run(Form1);
}
static void ontbenter(object sender, EventArgs args)
{
if (!(sender is TextBox))
return;
TextBox s = (TextBox)sender;
s.SelectAll();
}
static void ongotfocus(object sender, EventArgs args)
{
if (!(sender is TextBox))
return;
TextBox s = (TextBox)sender;
s.SelectAll();
}
}
}

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