Develop Reference

How to simulate keystroke in WPF, but outside the application?

Currently I used this snip code as a result from googling.
var eventArgs = new TextCompositionEventArgs(Keyboard.PrimaryDevice,
new TextComposition(InputManager.Current, Keyboard.FocusedElement, "A"));
eventArgs.RoutedEvent = TextInputEvent;
var flag = InputManager.Current.ProcessInput(eventArgs);
It was working if I used Keyboard.Focus(TxtBox); and the TxtBox will be filled with the Keystroke.
But what I want really achieved is:
1.Drawing a box (for example, I draw box on one of the excel cell)
2.Click on the box coordinate (to change Keyboard Focus)
3.Send Keystroke to clicked excel cell
I have done step 1 and 2.
But I can't find a way to do the third step.
Somehow, the click event (using mouse event) maybe not changing Keyboard Focus automatically.
So, how do I change Keyboard focus, if possible using coordinate ?
Or maybe can I get IInputElement from a coordinate ? and then set keyboard focus to it.
Of course, all of it outside from the main application window of the WPF.

Found it !
At:
Installed InputSimulator via NuGet, no members accessible
It is working in most cases.
I said in most cases, because it is able to type in other window like excel application, but on other custom app window. There might be a case it won't work.
Hope it help for other people, looking for the same thing.

Cannot read held state of key in WPF inside mouse event handler - Inconsistent behaviour in Windows guest on VMWare Fusion for Mac

This issue is caused by an inconsistent setting in vmware fusion - the secondary mouse function of MacOS (ie, right click) was being triggered by the control-left click, in spite of being configured in vmware fusion settings to send control through as a separate key.
I am leaving this here as it outlines the diagnostic steps taken to isolate the issue.
This behaviour might be present in other virtualisation solutions on MacOS.
This is not a duplicate - I have tried the approaches suggested - They Do Not Work. Genuine help is required please.
I am trying to implement a multiple select function in a WPF canvas, and need to be able to detect when either control key is held while clicking on an item.
I have already tried using the documented and accepted methods of getting the key (Keyboard.IsKeyDown and Keyboard.Modifiers) and although they are supposed to work, they do not in this case.
I cannot place a key handler in the main window of the application as this solution is implemented in a component, and as such, I do not have access to the main window.
I cannot create a keyboard OnKeyDown override, as it does not register the event. I do not know why this is, but suffice to say, I have tried all the methods I can find after an extensive search on Stack Overflow, and am currently out of ideas.
In the current logic, clicking an item in my canvas will clear any selected items already. If the control key is held, I will not clear selected items.
The structure of my application is as follows:
Main Window -> Dock Panel -> ScrollViewer -> Main Custom Component (extends Canvas) -> ChildCanvas objects (multiple instances, all also extend Canvas).
The component will not have any reference back to the main window - this is absolutely not negotiable.
The component must not require a reference to the main window to be passed in to it.
The component cannot rely on any logic, properties, methods or other functional code being placed in the MainWindow - it must be totally reusable.
Multiple instances of a custom object (ChildCanvas) which itself derives from Canvas are placed onto a base custom object (ExtendedCanvas) which also extends Canvas.
I am detecting the mouse click in a mouse event handler within my custom item.
Although I can in theory handle the key event and set a bool flag when the key goes down and clear it when the key goes up, this is not a reliable way to do things as it would require the focus to be on whichever component is handling the key.
All the examples I have looked at require a specific event handler for the key press, but I cannot apply that approach in this case as it simply does not seem to register the key press, even if the component where the event handler is implemented has focus at the time.
I would like to find a way to check if a key is held down in the mouse click handler if this is possible in WPF.
EDIT: I have tried using the Keyboard.Modifiers approach, but this returns no result.
EDIT: I have also tried Keyboard.IsKeyDown(Key.LeftCtrl), which does not return any values.
EDIT: I have tried to handle the key event globally by registering on the EventManager as shown. What I have found is that key up and key down events are triggered in quick succession. The first event has the property e.IsRepeat as false, and all subsequent event occurrences have e.IsRepeat set as true. Using these events, I have set a bool which is set to true in the first keyDown event is e.IsRepeat is false (the first initial key press), and set to false in the keyUp event if e.IsRepeat is false (the keyUp event fire when the key is physically released).
This does not work - clicking the item on the canvas when the key is held altered the state of the bool setting it to false.
This behaviour is totally inconsistent with what Microsoft document for the way the keyboard handling should work.
EventManager.RegisterClassHandler(typeof(Control),
Keyboard.KeyDownEvent,new KeyEventHandler(keyDown),true);
I can call Keyboard.IsKeyToggled(Key.LeftCtrl) which does show the toggled state, but it changes with every key press, and does not show me whether the key is held down at the time of the mouse click.
public class ExtendedCanvas:Canvas {
public ExtendedCanvas() {
MouseUp += thisMouseUp;
}
void thisMouseUp(object sender,MouseButtonEventArgs e) {
if ((Keyboard.Modifiers & ModifierKeys.Control) > 0) {
//This does not work - no key is registered, as for some reason, Keyboard.Modifiers does not register that the key is held.
}
//If CONTROL is held down
if (!ControlKeyHeldDown) {
ClearSelectedItems();
}
IsSelected = true;
}
}

The inconsistent behaviour is the result of a VMWare option.
This VM is being run on MacOS and in spite of VMWare Fusion being configured to send the Control key straight through, Control Click was still triggering the secondary mouse button (ie, right click in this case).
The solution is:
1) Shut down the VM.
2) In VMWare Fusion Preferences -> Keyboard And Mouse -> Mouse Shortcuts, ENABLE (Check) the "Secondary Button" option if it is not checked.
3) Close the preferences window to save the settings.
4) Close VMWare Fusion
5) Reboot the host system
6) In VMWare Fusion Preferences -> Keyboard And Mouse -> Mouse Shortcuts, DISABLE (UnCheck) the "Secondary Button" option.
7) Start the VM, and confirm that Control Click no longer triggers the secondary click.
This option had been configured to send Control straight through prior to upgrading VMWare Fusion from 8 to 10.
It appears that although the Secondary Function checkbox was unchecked, the property was set to true, and it was behaving inconsistently from the way the settings suggested it should.

How to block a window as if Dialog window was displayed

I have a form which I would like to block during execution of an async event. I would like to achieve an effect similar to when a dialog window is displayed, without displaying or creating one.
I don't want to manually disable controls on the form, as some controls may be added in the future (not necessarily by me). I would like to avoid disabling the entire form / user control for aesthetic reasons.
Is there a standard/elegant way of achieving this, or am I going in a wrong direction?

You can block WinForm window by setting it's Enabled property to false, but it will prevent user from any action with that window (like moving, resizing or hiding) and it may be very annoying. Consider showing some load indicator instead.
I would not recommend to disable controls without making them look disabled because it could confuse user.
Edit: As #AvoNappo pointed out window behavior differs depend on where to set Enable property to false:
if you set it in the constructor user still will be able to move/minimize/close window;
if you call it after constructor window control buttons and windows movement also will be blocked.

Detect change of focus and find it C#

I need an underlying process to gather information about other applications used by Windows. I suspect this would be done using WAPI hooks. What I wish to do is for my program to detect when windows changes focus from one program to another and tell me which one currently has focus.
First I need an event that triggers each time Windows swaps focus between two applications. All events I've found so far only handles changes made from or to the program it's being used by, but I need to find all focus-changes, even if it's between two other programs.
I'll also need a function that gives me the window in focus. Would this work, or is this only internally (windows within the current application and not other programs)?
Cheers

Depending on how accurate you need your focus change detection system to be you might be able to get away with a service that polls for the foreground window using the API function you described GetForegroundWindow (yes this is system-wide, not process specific).
You can then use the handle of that function to determine which process is the current active/focused process. Then retrieve the focused element (child window) of that process..
HWND hwnd = GetForegroundWindow();
DWORD remoteThreadId = GetWindowThreadProcessId(hwnd, NULL);
DWORD currentThreadId = GetCurrentThreadId();
AttachThreadInput(rThreadId, curThreadId, TRUE);
HWND focusElement = GetFocus();
AttachThreadInput(rThreadId, curThreadId, FALSE);
Keep doing this.. and do whatever you need to do with focusElement
UPDATE
Well, apparently, as #Kenneth K. posted in a comment, there is a global EVENT_SYSTEM_FOREGROUND event that you can hook so that you application gets notified when the foreground (focused) window changes. This way you don't need to loop continuously to detect these changes.
EVENT_SYSTEM_FOREGROUND = 3;
WINEVENT_OUTOFCONTEXT = 0;
You can follow the example in this answer to see how to hook this event and get the notifications. Then whenever the foreground (focused) window changes you can hook that window's message loop and look form focus changed events withing that window using the SetWindowsHookEx function.
Another options is to consult the list of system events on MSDN and see if there is one you can use instead of the EVENT_SYSTEM_FOREGROUND, or along with it to detect control-level focus events. Perhaps the EVENT_OBJECT_FOCUS might be useful.
Please let me know if this is still unclear..

Retain focus on a UI element, but click a button on a different dialog. WPF C#

I am developing a touchscreen friendly app that also includes a virtual keyboard. My virtual keyboard is in its own window, allowing it to be moved around. The problem is that when I click on a key on the keyboard the text box on the main application window no longer has focus. The switch from the main application being the active window to the keyboard dialog being the active window means that any field on the main window no longer has focus. How can I get around this?
I tried setting the keyboard window as not focusable. Though this is probably good to set, it did not solve my problem.

You could just return focus to the original window asynchronousely:
public static void BackgroundFocus(this UIElement el)
{
Action a = () => el.Focus();
el.Dispatcher.BeginInvoke(DispatcherPriority.Background, a);
}
But this is not ideal, because the original window caption would flicker when losing focus...
Why don't you use Popup instead?

Check out the function SetForegroundWindow() ,
I have used this long time back some where in my project
May be this may help you

Using a Popup, as already suggested, seems like a good solution. As for your custom window, try setting the Window.ShowActivated to false.