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How do you programmatically create new controls inside a custom WPF Panel implementation?

I'm creating an OverflowPanel derived from the WPF Panel class. The intent is that it will fill with items in a single direction, and when there are too many items to display, excess items will be removed and replaced with another control to hold the overflow. Think of a website's breadcrumbs, or the address bar in Windows File Explorer. This is a .Net Core 3/C# 8 project.
I have a partially working solution: I've inherited from Panel and overridden MeasureOverride() and ArrangeOverride() to get the behavior I want. My problem now is getting a button or some other control to display in place of the items being removed.
My initial, naive approach was to just create a Button in code and try to Measure/Arrange it.
public class OverflowPanel : Panel
{
// First by itself, but I did also try to host this in a new UIElementCollection
private readonly Button _overflowButton = new Button();
public override Size MeasureOverride(Size availableSize)
{
...
_overflowButton.Measure(availableSize);
// Do stuff with _overflowButton.DerivedSize.
...
}
// Also attempted to draw int in ArrangeOverride()
}
This did give me non-zero result for the measurement. (I put some dummy content in the button.) My algorithm gives me space on the screen where the button should go, however, nothing gets rendered there.
I also confirmed that there wasn't simply a button being drawn with no visual style, by inspecting the Live Visual Tree in Visual Studio.
I tried to make a UIElementCollection and add the button to that to see if it would add it to the visual tree, but this also did not work.
Most Google/StackOverflow results I've seen suggest something along the lines of this.Children.Add(_overflowButton), but this does not work when hosted inside an ItemsControl, as it takes over managing the collection of objects and throws an exception if you attempt to mess with it.
After digging around in the code for Panel and UIElementCollection, I noticed that Panel lets you override
UIElementCollection CreateUIElementCollection(FrameworkElement logicalParent)
to use a derived implementation of UIElemenetCollection. I created a PinningUIElementCollection to trick WPF into rendering the extra element. It stores extra items and then slips them in whenever the iterator is accessed. It also does index mangling to access both the extra collection of items and the automatically generated one.
This actually worked. My button is now displayed (albeit without the correct styling, but that's a separate issue.)
However my issue with this approach is that it seems like a lot of work. It also seems error prone: I could easily miss when it tries to use a numerical index and forget to mangle it, causing unpredictable results.
Is there a simpler/more straightforward way, in my derived Panel implementation, to display an extra button or some other arbitrary control with only a few less hoops?

Appropriate way to force loading of a WPF Visual

I have been struggling with printing using the System.Printing namespace. I have finally figured out that the reason I was getting blank results when using portions of the API was because the Visual objects I was trying to print were not Loaded/Initialized. If I display the Visual objects by putting them in an appropriately-sized Windows and calling Show() prior to printing, I then get the expected results.
Thus, the workaround I came up with was to call this method for every Visual
public static void ShowVisual(Visual visual)
{
Window window = new Window
{
Content = visual,
SizeToContent = SizeToContent.WidthAndHeight,
Visibility = Visibility.Hidden
};
window.Show();
window.Close();
}
This seems like a hack, especially since the user briefly sees the Window-frame draw. I figure there must be a different way it is supposed to be done. However, I am not turning up any other solutions. Is using a hidden Window really what is supposed to be done here?
Using a MenuItem as described at WPF - Get size of UIElement in Memory? does not work. I looked at Force rendering of a WPF control in memory but I am not really wanting to render the Visual to a bitmap which seems to be what that is for. Calling ApplyTemplate() on the Image that as described in wpf force to build visual tree did not help.
EDIT: This is the solution that is used instead of ShowVisual from above
/// <remarks>
/// This method needs to be called in order for
// the element to print visibly at the correct size.
/// </remarks>
private static void ArrangeElement(UIElement element)
{
var box = new Viewbox {Child = element};
box.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
box.Arrange(new Rect(box.DesiredSize));
}

The items you want to print need to be added to the visual tree in WPF in order for the Measure and Arrange processes to be called on all the elements in the visual tree you want to show / print or otherwise display.
I haven't done this for a while but you may find that adding these items to a ViewPort in the background and then printing them solves the issue. This should get around the need for actually displaying them on the screen and thus the user seeing them whilst also forcing the Measure / Arrange processes.

I had the same problem. In my case I only call: Visual.UpdateLayout() before trying to work with it. As said by Jammer, it will automatically force Measure / Arrange processes.
I did it on window. If you have any problem, you probably should set the Visual Height and Width before call UpdateLayout().
Eric

I had the same issue. Solved by ApplyTemplate().
It force to builds visual tree of an Framework element.

C# Label Properties won't update upon resize

I recently started getting acquainted with Visual Studio 2010 and C# for an internship. C# doesn't include a built-in InputBox function, so I made my own form, with a text box, two buttons and a simple label.
I have a function set up to allow the programmer to call the form in regular format (where the user enters input via the textbox) or yes/no format (where the form just displays a question and the yes and no buttons).
When I switch over to yes/no format, I want to center the label programmatically. I've been using the code:
labelNote.Left = inputBox.Left + (inputBox.Width / 2) - (labelNote.Width / 2);
This should put the center of the note in the center of the form. However, if the contents of the label change (making the new label longer or shorter) the properties don't update to reflect the new size. It won't center unless it includes the original text. Is there some way to force an update? I foresee this becoming a problem with positioning objects for scalability in the future.
Thank you for your time

I'm assuming you have the sizing within an actionlistener. Specifically the forms' resize action listener. Then whenever the form is resized it is called and all of you code is recalled. Then to force an update from somewhere else you just have to call the actionlistener.
Actionlistener:
Private Sub formName_Resize(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Resize
Calls actionlistener:
formName_Resize(sender, e)

Well, you could attach an event to Label.TextChanged. Frankly it would be better to change the TextAlign or something like that though: try to perform the layout in a declarative fashion instead of doing it explicitly through code. That tends to make things work rather better.
I've found the [TableLayoutPanel]1 control to be reasonably easy to work with - most of the time (and occasionally a complete pain).

It turns out that I made a stupid mistake (a common theme for me in debugging. The really small stuff goes unnoticed for the longest amount of time).
The label resizing was not the issue. The issue was the order in which I changed the contents of the label and then called the function to calculate its new location. I was calling the location calculation first, so it found where to center the label based on the old contents. I didn't notice for so long, because the text was changing properly. I took it for granted that the functions were being called in the correct order.
So, when it doubt, check the order in which you're writing your code. Thanks for you help anyway, everyone. I ended up finding out some neat things that could be applicable to other scenarios (such as the MeasureString function in the Graphics class).

Bring Winforms control to front

Are there any other methods of bringing a control to the front other than control.BringToFront()?
I have series of labels on a user control and when I try to bring one of them to front it is not working. I have even looped through all the controls and sent them all the back except for the one I am interested in and it doesn't change a thing.
Here is the method where a label is added to the user control
private void AddUserLabel()
{
var field = new UserLabel();
userContainer.Controls.Add(field);
SendLabelsToBack(); // Send All labels to back
userContainer.Controls[field.FieldName].BringToFront();
}
Here is the method that sends all of them to the back.
private void SendLabelsToBack()
{
foreach (var label in userContainer.Controls);
label.SendToBack();
}

Yeah, there's another way. The Controls.SetChildIndex() also changes Z-order. The one with index 0 is the one on top. Doesn't buy you anything though, BringToFront() uses this method.
Your SendLabelsToBack() method as given cannot work, it will also send the label to added to the back. But your next statement fixes that again.
Okay, that doesn't work, which means the BringToFront() method doesn't get executed. Look in the Output window for a "first chance exception" notification. As written, your SendLabelsToBack() will cause an exception if the user control contains any control other than a UserLabel. Also, set a breakpoint after the BringToFront() call and check the value of userContainer.Controls[0].Name when it breaks.

Controls' z-index is per-container.
If you call BringToFront on a control that is inside a container (such as a Panel), it will not bring the container to the front.
Therefore, the control will only go in front of other controls in that container.
To see what containers your controls are in, you can use the Document Outline pane in the View menu.
EDIT: Your userContainer control is probably behind a different control.

Have you tried Invalidate() after BringToFront()? BringToFront does not raise the Paint event
try this:
private void SendLabelsToBack()
{
foreach (var label in userContainer.Controls)
{
label.SendToBack();
label.Invalidate();
}
}

I think you just need to change your last line:
userContainer.Controls[field.FieldName].BringToFront();
to this:
userContainer.Controls[field.Name].BringToFront();
When you use a string as the indexer for the Controls collection, it goes by the Name property of the control (not the FieldName property).
Since you're just trying to bring the most recently-added control to the top, this would also work:
userContainer.Controls[userContainer.Controls.Count - 1].BringToFront();

From my experience looks like windows puts all controls belonging to one graphic container(pane, group box...etc) in a software collection. The collection is ordered by child index which is a property of every control in that container.
The trick is that children with the same index can and do exists. In this case windows will paint those children ordered relative to others but between them it will paint them in the reverse order they had been added to the container.
Long story short: for one container-you need to make sure controls have different indexes by changing ALL NOT just SOME of the indexes when you want to change the z-order. For example:
foreach (Control newControl in TopControl.Controls)
{
TopControl.Controls.SetChildIndex(newControl,indexlogic(newControl));
}
where indexLogic(newControl ) is your method of calculation of the index of particular control.

Override OnPaint

If I override OnPaint and draw a square on the control, how do I get that e.graphics.draw... to show up when I'm previewing it in the designer?

http://msdn.microsoft.com/en-us/magazine/cc164048.aspx
http://msdn.microsoft.com/en-us/magazine/cc164145.aspx
While you could manually register with
Control.OnPaint to add your design
time UI, you'll find that overriding
OnPaintAdornments is a better option
because it is only called after the
control's design-time/run-time UI is
painted, letting you put the icing on
the cake (see Figure 20). Simply
adding DesignerAttribute to the
ClockControl class completes the
association: Copy Code
[
Designer(typeof(ClockControlDesigner))
] class ClockControl : Control { ... }

If you're trying to draw a focus rectangle for you control, and have it be visible when manipulating your control after it has been added to a form, then Gaijin42's approach should work.
If you're trying to see what your custom drawn control looks like...
If you've overriden the OnPaint method in the control, you should see the results of that OnPaint when you look at your control after it has been added to a form (or another control).
If you're trying to see the results of the Paint when looking at the designer for the control itself, I don't think that is possible (at least it wasn't with VS2005):
Unfortunately this is not possible.
While you're writing the behaviours
of the user control the code isn't
compiled and the designer actually
uses an ordinary user control to host
the child controls. The OnPaint
override etc will not run.
To debug the overrides in your control
you need to run it in some sort of
host. VS2005 provides a new control
host for this purpose but I find that
even this is not sufficient sometimes.