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Allow clicks and click-through's

I have a Grid over a Button (They are both directly on another Grid, but the Grid is "above"). I need to subscribe to certain events in the Grid, but still be able to click on the Button. I set the Background of the Grid to Transparent, to get it to raise events, but then the Button isn't clickable. Is there any way to leave IsHitTestVisible = true but let the click go to the next element as well?

I'd first look at whether you can put the button above the grid. You can just move it in the XAML - the further down an element declaration is in the XAML, the higher the z-order.
If you definitely cannot do this, you could override the UI element MouseUp or MouseDown methods and control the setting of the handled property to allow the subsequent elements in the tree to take the clicks.
If you only wanted to restrict this to a specific control, you could inspect the "OriginalSource" property (since all these event args inherit from RoutedEventArgs) to see what the source of the click was and act accordingly:
protected override void OnMouseDown(MouseButtonEventArgs e)
{
var grid = e.OriginalSource as Grid;
if (grid != null && grid.Tag = "yourgridname") e.Handled = false;
}

Capture KeyDown when event does not reach my control

First: I know that there are literally thousands of answers like: "Add a handler to Keyboard.KeyDownEvent and have fun!". But in my situation this does not work.
I have a custom control CustomControl which derives from Canvas but has no Children. Instead it draws its "children" directly to the DrawingContext in the OnRender. My Control is HitTestVisible, it is tab stop but is not focusable. It is often reused and sometimes in a ScrollViewer.
This CustomControl has a custom implementation for selecting something like text, and should copy that selected text to the ClipBoard on Ctrl+C.
To do this, I added a handler in the constructor:
public CustomControl()
{
//// ... other stuff
AddHandler(Keyboard.KeyDownEvent, (KeyEventHandler)CopyMarkedNucleotidesToClipboard);
}
And here is the Problem: When my control is inside a ScrollViewer, and I hit Ctrl+C, the KeyDownEvent is raised on the ScrollViewer and bubbles up to the window, and therefore never reaches my Control.
What can I do inside my CustomControl to capture every Ctrl+C in the window where it resides?
PS: I already set IsTabStop="False" and Focusable="False". But then the next sibling of the ScrollViewer would raise the event which would still bubble up to the window. And I don't want to go through all controls which are higher in the visual tree and set IsTabStop="False" and Focusable="False" which would be wrong...
I already found this article http://blogs.msdn.com/b/toub/archive/2006/05/03/589423.aspx but I think, that there must be a more wpf-like way!

The suggestion of Sinatr was correct! Thanks!
The solution is to find the parent window in the load and subsribe to his KeyDownEvent.
public CustonControl()
{
Loaded += HookToCtrlC;
}
private void HookToCtrlC(object sender, EventArgs e)
{
var parentWindow = Window.GetWindow(this);
parentWindow.KeyDown += CopySelectedTextToClipboard;
}
private void CopyMarkedNucleotidesToClipboard(object sender, KeyEventArgs e)
{
Clipboard.SetText("Hello World!");
}

Adding Click Handler On UserControl Breaks Click On Children

I have a user control that I'm trying to make draggable. The whole control should be draggable except when you click on buttons or text boxes. I'm handling the mousedown, mouseup and mousemove events on the usercontrol itself and I can drag by clicking anywhere. The only issue is now I can't click any buttons on the user control. Any clue what's going on?
Code is something like this:
<UserControl PreviewMouseLeftButtonDown="Popup_PreviewMouseLeftButtonDown" ....STUFF...>
<!-- CAN'T CLICK THIS -->
<Button />
<UserControl>
Code Behind:
public void Popup_PreviewMouseLeftButtonDown(object sender, MouseEventArgs e)
{
mouseDown = true;
oldMousePosition = this.PointToScreen(e.GetPosition(this));
this.Popup.Child.CaptureMouse();
}

The issue arises when you use CaptureMouse() - this permanently captures all your mouse input on the window, and makes it so that you're unable to click on anything within the Window. I don't know if it's different for you, or if you checked, but it's not (just) that the Button is unclickable - it's that literally everything on the Window is unclickable.
You have to actually do something with the mouse after you've captured it, and then once you finish that, you have to return normal control by calling Mouse.Capture(null). For you, this would probably be best to do in your MouseUp() method.
However, this still leaves the child problem. I can't really think of any way you're going to be able to both capture all mouse click events on a parent control and allow them to get to the child control. I suppose you could check the mouse position against the button position, both relative to the UserControl, then route the click event to the Button every time, but this seems a little overelaborate. Is there a reason you can't just add a full-sized Grid to the UserControl with a lower ZIndex than the Button, and just use that to detect if a click was made inside the UserControl but not on the Button?

WinForms Event Parent scroll

I have two FlowLayoutPanels on a form: PanelA and PanelB. Each will be populated at run-time with multiple controls, such that the panel will scroll (i.e AutoScroll is true).
Here's the issue: The controls that the panels are populated with each contain a ComboBox. Thus, MouseWheel events are consumed by the combo box instead of by the panel. I want MouseWheel events to be consumed by the panel.
If there's no scrollable control on the child controls, then the MouseWheel event skips the child control (which doesn't handle it) and hits the panel, which does handle it. How can I set my child control's combo box to ignore the MouseWheel event? Can I tell it to re-raise the event?
I tried just applying Focus to the Parent whenever one of the child controls ticks the 'MouseEnter' event; this fixed the scrolling issues, but also left the child controls completely un-editable.
Something else I've found from digging around involves fiddling with the Windows API directly, but I find it hard to believe that something like that is required for this.

I tested the following code and it seems like a solution to your issue. Basically you need to focus the 'FlowLayoutPanel' when you click on it, or your mouse enters it:
private void newCheckListQuestionPanel_Click(object sender, EventArgs e)
{
newCheckListQuestionPanel.Focus(); //allows the mouse wheel to work after the panel is clicked
}
private void newCheckListQuestionPanel_MouseEnter(object sender, EventArgs e)
{
newCheckListQuestionPanel.Focus(); //allows the mouse wheel to work after the panel has had the mouse move over it
}
Source

MouseEnter and MouseLeave events from a Panel and its child controls

I have a Panel that contains child controls.
If I handle the Panel's MouseEnter and MouseLeave events, and its child's MouseEnter and MouseLeave events, the events are raised in this order:
Panel.MouseEnter
Panel.MouseLeave
Child1.MouseEnter
Child1.MouseLeave
Panel.MouseEnter
Panel.MouseLeave
But I need the following order:
Panel.MouseEnter
Child1.MouseEnter
Child1.MouseLeave
Panel.MouseLeave
Is that possible?

If you dont mind creating a usercontrol(derived from the panel or other parent container you wish),
Override your parent's OnMouseLeave method to look like the following..
protected override void OnMouseLeave(EventArgs e)
{
if(this.ClientRectangle.Contains(this.PointToClient(Control.MousePosition)))
return;
else
{
base.OnMouseLeave(e);
}
}
Then, the event raising will be in the required order.

The mouse is "leaving" the panel as it enters the child control which is why it fires the event.
You could add something along the following lines in the panel MouseLeave event handler:
// Check if really leaving the panel
if (Cursor.Position.X < Location.X ||
Cursor.Position.Y < Location.Y ||
Cursor.Position.X > Location.X + Width - 1 ||
Cursor.Position.Y > Location.Y + Height - 1)
{
// Do the panel mouse leave code
}

The solution is to track the number of enters/leaves.
In you overall control add a counter:
private int mouseEnterCount = 0;
In the MouseEnter handler do this:
if (++mouseEnterCount == 1)
{
// do whatever needs to be done when it first enters the control.
}
In the MouseLeave handler do this:
if (--mouseEnterCount == 0)
{
// do whatever needs to be done when it finally leaves the control.
}
and do the above MouseEnter and MouseLeave event handlers for ALL the child controls as well as the containing object.

Matthew's answer will not work always. Especially if the child control is set to the edge of its container and the mouse moves off the controls in that direction. You will never detect the MouseLeave event.
The best approach is to create a user control container then hook all the child controls' MouseEnter and MouseLeave events so that you can properly detect when and where the mouse is at all times. THEN if it enters your container's bounds you can fire a custom MouseEnter event and when it leaves MouseLeave event.

Jimmy T. is right. There will be problems if there is no (or small) space betwean Parent Control (Panel) edge and Child Control.
This is how I solve this problem in UserControl-derived class:
public CSStackPanelItem()
{
InitializeComponent();
MouseEnter += new EventHandler(CSStackPanelItem_MouseEnter);
foreach (Control child in Controls)
{
child.MouseEnter += (s, e) => CSStackPanelItem_MouseEnter(s, e);
child.MouseLeave += (s, e) => OnMouseLeave(e);
}
}
protected override void OnMouseLeave(EventArgs e)
{
if (this.ClientRectangle.Contains(this.PointToClient(Control.MousePosition)))
return; //suppress mouse leave event handling
if (m_bIsHover)
{
m_bIsHover = false;
Invalidate(); //actually my mouse Enter/Leave event
}
base.OnMouseLeave(e);
}
void CSStackPanelItem_MouseEnter(object sender, EventArgs e)
{
m_bIsHover = true;
Invalidate(); //actually my mouse Enter/Leave event
}

This may not be the most elegant solution, but you could set a property in the parent control panel (subclass panel) that is a bool value like "bool selected". Then when the MouseEnter for the panel fires set it to true...then stop the mouseleave logic from firing unless it is set to false.
example
bool selected;
MouseEnter(..,..)
{
if (!selected)
selected = true;
else
selected = false;
if (selected)
/.. Logic Here ../
}
MouseLeave()
{
if (selected)
return;
/.. Logic Here ../
}
In reality I would just have the MouseLeave event of the child set the parameter.
Example:
Parent:
bool doLeave;
MouseLeave(..,..)
{
if (doLeave)
{
/.. Logic ../
doLeave = false;
}
Child:
MouseLeave(..., ...)
{
DerivedPanel parent = this.Parent as DerivedPanel;
if (parent != null)
parent.doLeave = true;
}
Neither are elegant but it will work.

I believe so. A nice tool to have for verifying your WinForms application's events.
Windows.Forms Order of Events
http://missico.spaces.live.com/blog/cns!7178D2C79BA0A7E3!186.entry
Created with EventSpy written by Urs Eichmann. (ftp://missico.net/EventSpy.zip)
Using .NET Framework 3.5 and with Visual Basic’s Application Framework enabled.

This is a tricky one, and will be difficult to code reliably for. One idea is to "capture" the 3 incoming events in a list and execute your desired code once the list is complete (has the 3 desired events in the list). Then when you're done executing whatever code (or perhaps capture the combo of events in reverse), you could empty your list and have it ready for the next time that particular combo-event happens. Not ideal, but just a thought.
Of course, that doesn't overcome the potential resolution issues & possible missed events Hans raised. Perhaps more context is in order.

Check the child component..
if (panel1.GetChildAtPoint(panel1.PointToClient(Cursor.Position)) == null)
{
// mouse leave panel and children
}

My solution was to create a MouseEnter event for the panel and for the parent form of that panel. I don't tie to any MouseLeaving events.
When the cursor enters the panel, MouseEnter fires. I can visit all of the panel child controls and nothing happens (which is what I want). When I leave the panel, the parent form's MouseEnter fires.

I was looking for a solution to this problem so I could make a panel act like a button (ie change color when the user hovers over it). I found the simplest solution was to put another panel over the base panel (and over all it's controls) and make the new panel's BackColr Transparent (highlight the whole BackColr property and type in "Transparent"). Then add the MouseEnter and MouseLeave events to the new panel and make them perform whatever you want (change the background color of the base panel). The user still sees all the controls that are on the base panel but the base panel's mouse leave and mouse enter don't fire as the user moves the mouse over the controls. The user can't interact with the controls on the base panel but for a simple button type control this works OK. Just add a the mouse click event handler to the new panel.