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Form.Width incorrect on Form.FormClosing()

I am trying to get an accurate Form.Width on FormClosing().
I have a zoom() method I use to scale a picture in the Form. The form's width is then manually re-sized by me to fit. I then, set the MaximumSize's Width limit to the new width of the form. For our purpose, let's say the width and maxwidth are now 1386.
If I re-size the form in the Windows interface by dragging its edge to the left, the width is being reduced just fine. FormClosing reports the re-sized width accurately. Let's say 1107.
However, if go through the zoom() method I wrote, even though I drag to the left to the same position, FormClosing is reporting the ORIGINAL 1386 width. The only things I do to form size in the zoom() method are set width and maxwidth.
I am at a loss to handle this behavior. I need FormClosing to report the correct size. I think FormClosing is setting the Width to MaximumWidth when it fires. I think I read something about how the Form is set to Hidden by the time the FormClosing event is fired. Maybe being Hidden reverts its size to MaxWidth.
Any help would be much appreciated. I have been struggling with this for a few hours and can't find anything.
Thanks.
Here is the relevant code:
private void zoom()
{
// Re-size form width to slightly more than page width.
// This is percentage-based, meaning 100 = default size.
Size picSize = new Size
{
Width = (int)(originalRenderingSize.Width * integerUpDownZoom.Value / 100),
Height = (int)(originalRenderingSize.Height * integerUpDownZoom.Value / 100),
};
// some code here which I commented-out, and still, the problem exists.
// Set maximum to prevent ugly sizing.
this.MaximumSize = new Size(picSize.Width + 40, Screen.FromControl(this).WorkingArea.Height);
// The problem is this: When this method processes, as shown, a page is rendered and sized according to
// a user-provided zoom level represented by an integerUpDown control. Once rendered, the form should
// re-size its width to match the newly-scaled page's width. This works, too. So far, so good.
//
// But!!! If the user grabs the right side of the form and drags it to the left to reduce the width
// of the form (mind you, this is Windows OS doing this), upon Form.Form_Closing(), you can see a
// quick flash of the form fully-open and unscrolled. Then, in the FIRST line of Form_Closing(),
// the debugger reports the form's width as the fully-open and UNSCROLLED width.
//
// The goal is to set the width upon the conclusion of this zoom, but then, on closing
// get the width of the Form in order to persist it for use the next time the app is run.
//
// 2 options have been tried. Both cause Form_Closing to erroneously report the fully-open width.
// But if BOTH are commented-out, the re-sizing occurs and Form_Closing() reports properly the
// form's scrolled width.
// Bear in mind that Form_Closing is one of those things that can happen anytime or never. This means
// the bug is triggered by EITHER and ONLY the two options below.
// Option 1: Tried first. It sets the width fine.
//
// this.Width = picSize.Width + 40;
// Option 2: It also sets the width fine.
// I think this option causes width to change (it invokes width change, and somewhere in the
// OS's width change, the error occurs.
//this.MinimumSize = new Size(MaximumSize.Width - 1, this.Height);
//this.MinimumSize = new Size(0, 0);
}
Edit: I have new information which should help. The culprit is FormClosing(). Here's what I did: I re-sized the form in Windows until it occupied maybe 500 pixels in width. The horizontal scrollbar on my panel was showing. Then, in the FormClosing event, I added the line: Form.Show(). After that, I put a MessageBox.Show("Hi."). Sure enough, the Show() caused the form to repaint in its full, unscrolled width. It did not maintain its scroll state.
I think I have the solution and will post back after trying. Namely, I need to check Scroll values and operate on those values as well.
Edit 2: FormClosing() also re-sets HorizontalScroll.Value and VerticalScroll.Value to 0. This is a bummer! I wonder how to work around this. I also looked at e.Cancel, but there seems to be no way to take advantage of it, either. It seems e.Cancel just re-shows() the form in its unhidden state.
Sorry I cannot post the code. It would be pointless anyway. Think about it. The Windows OS handles the resizing. Not me. When the user re-sizes the form, it's all on Windows. If user re-sizes the form to 500 pixels wide, but FormClosing() reports it is 1386 pixels wide, no amount of my coding will show us anything new. This is a behavior issue. There is no code to show you how the Windows OS handles form re-sizing.

On FormClosing Event Use:
MessageBox.Show(this.Width.ToString());
You're using another Instance of your form's class, Form.Show() should not work in this event cause Dispose function is called and if you have referenced the same instance it will be disposed as well.

Resizing User Control - anchor controls to center of form

I have a user control which consists of two controls and four buttons, arranged on a Form: the two controls are on the sides and the buttons in the middle in a vertical row.
When using the control in an app, I place it on a form.
Now, when re-sizing the form horizontally, the two controls just move left or right w/o changing their size.
What I need is that the controls stay anchored to the middle of the form and grow to the sides (sorry about the lack of clarity, I prepared screenshots but the site wouldn't let me attach them).
Is there a way to accomplish this without overriding the Resize event?

Use a TableLayoutPanel as base for your user control.
You need 3 columns and one row. The middle column needs to have a fixed size, and the other 2 you set to 50%. Not to worry, .Net is smart enough to calculate the percent they actually take.
Inside the right and left columns you put your controls and set the Dock property of both to fill. In the middle column you put a panel and set it's Dock property to fill as wall, and In that panel you put the buttons in the middle.
Set your table layout panel Dock to fill as well, and when adding the user control to the form use Dock top, bottom or fill as well.

Erratum:
The above code works most of the time, but it fails for certain Move-Resize sequences. The solution is to respond to the Move and Resize events of the parent form (the consumer of the control), not of the control itself.
One more thing: due to the event firing order (Move first followed by Resize, had to move the working code from Resize() to Move(), which seems counterintuitive but it seems the right way nevertheless.

It seems indeed that it cannot be done in the Designer, but here is the solution using overrides.
It works ok, except for some control flickering which I haven't been able to overcome.
public partial class SB : UserControl
{
//variables to remember sizes and locations
Size parentSize = new Size(0,0);
Point parentLocation = new Point (0,0);
......
// we care only for horizontal changes by dragging the left border;
// all others take care of themselves by Designer code
public void SB_Resize(object sender, EventArgs e)
{
if (this.Parent == null)
return;//we are still in the load process
// get former values
int fcsw = this.parentSize.Width;//former width
int fclx = this.parentLocation.X;//former location
Control control = (Control)sender;//this is our custom control
// get present values
int csw = control.Parent.Size.Width;//present width
int clx = control.Parent.Location.X;//present location
// both parent width and parent location have changed: it means we
// dragged the left border or one of the left corners
if (csw != fcsw && clx != fclx)
{
int delta = clx - fclx;
int lw = (int)this.tableLayoutPanel1.ColumnStyles[0].Width;
int nlw = lw - delta;
if (nlw > 0)
{
this.tableLayoutPanel1.ColumnStyles[0].Width -= delta;
}
}
this.parentSize = control.Parent.Size;//always update it
this.parentLocation = control.Parent.Location;
}
//contrary to documentation, the Resize event is not raised by moving
//the form, so we have to override the Move event too, to update the
//saved location
private void SB_Move(object sender, EventArgs e)
{
if (this.Parent == null)
return;//we are still in the load process
this.parentSize = this.Parent.Size;//always update it
this.parentLocation = this.Parent.Location;
}
}
The above code works most of the time, but it fails for certain Move-Resize sequences. The solution is to respond to the Move and Resize events of the parent form (the consumer of the control), not of the control itself.
One more thing: due to the event firing order (Move first followed by Resize, had to move the working code from Resize() to Move(), which seems counterintuitive but it seems the right way nevertheless.

Locate a label on a form using relative position in Winforms C#

I have a winforms with a label on the main form and I am looking for a way to set the label in % of the form size. So, even if the form is re-sized and the label is set to y = 10% and x = 10%, not matter how the form will be re-size the label remains to the same location. I have tried to use the x and y location, but does not work. Thank you for any help and advice.
EDIT:
Let's say I have an image on my form and the label is set to just above IP Network. So, when the form is re-sized the label should also adjust and still be more or less above the IP Network.

The simplest way to do this, is to handle the ResizeEnd event of the form.
Inside this event, you can then calculate the relative position as follow
private void SampleForm_ResizeEnd(object sender, EventArgs e)
{
lblSample.Location = new Point(Convert.ToInt32(((double)this.Size.Width * 0.1)), Convert.ToInt32(((double)this.Size.Height * 0.1)));
}
Naturally this setting can be added to a refactored method that takes a Size and % value in and outputs a Point object for easier reuse across the solution.

Is there a way to get the bounds of a TabPage in a Winforms TabControl?

I have a Form with only a single TabControl, with many tabs, where each tab has only square buttons side by side. I am trying to make it so that when the user clicks on a tab, the form resizes itself to a size where you can see all the buttons in a particular tab or a size where you can see all the tabs, whichever is greater.
I am just curious if there is a way to query where the last control in a tab page is? So I can just do something like:
tabForm.Width = currentTabPage.UsedContentBorder + 10;
Or do I have to do this by adding all the controls and the sizes between them, etc?

You want to find out the maximum coordinates of all controls in a specific tab? Easy with LINQ:
int right = tab.Controls.Cast<Control>().Max(c => c.Right);
int bottom = tab.Controls.Cast<Control>().Max(c => c.Bottom);
Now, to properly choose the size of the form, I imagine you just have to figure out how much larger the Form is than its TabPages... I would guess something like this:
int extraWidth = form.Width - tabControl.SelectedTab.Width;
int extraHeight = form.Height - tabControl.SelectedTab.Height;
Then you just do
form.Size = new Size(right + extraWidth, bottom + extraHeight);
(the TabControl will resize automatically if its Anchor property is set to all four sides.) It occurs to me that this may malfunction if the user resizes the form very small... you may be able to compensate by calculating extraWidth and extraHeight in the Form.Load event and then saving those values for when you need them later.

Centering controls within a form in .NET (Winforms)?

I'm trying to center a fixed size control within a form.
Out of interest, is there a non-idiotic way of doing this? What I really want is something analogous to the text-align css property.
At the moment, I'm setting the padding property of the surrounding form to a suitable size and setting the Dock property of the control to fill.

You could achieve this with the use of anchors. Or more precisely the non use of them.
Controls are anchored by default to the top left of the form which means when the form size will be changed, their distance from the top left side of the form will remain constant. If you change the control anchor to bottom left, then the control will keep the same distance from the bottom and left sides of the form when the form if resized.
Turning off the anchor in a direction will keep a control centered when resizing, if it is already centered. In general, a control not anchored maintains its proportional position to the dialog. E.g. If you put a control at X=75% of the dialog width and turn off left/right anchors, the control will maintain its center at X=75% of the dialog width.
NOTE: Turning off anchoring via the properties window in VS2015 may require entering None (instead of default Top,Left)

myControl.Left = (this.ClientSize.Width - myControl.Width) / 2 ;
myControl.Top = (this.ClientSize.Height - myControl.Height) / 2;

Since you don't state if the form can resize or not there is an easy way if you don't care about resizing (if you do care, go with Mitch Wheats solution):
Select the control -> Format (menu option) -> Center in Window -> Horizontally or Vertically

I found a great way to do this and it will work with multiple controls. Add a TableLayout with 3 columns. Make the center column an absolute size (however much room you need). Set the two outside columns to 100%. Add a Panel to the center column and add any controls you need and place them where you want. That center panel will now remain centered in your form.

To center Button in panel o in other container follow this step:
At design time set the position
Go to properties Anchor of the button and set this value as the follow image

In addition, if you want to align it to the center of another control:
//The "ctrlParent" is the one on which you want to align "ctrlToCenter".
//"ctrlParent" can be your "form name" or any other control such as "grid name" and etc.
ctrlToCenter.Parent = ctrlParent;
ctrlToCenter.Left = (ctrlToCenter.Parent.Width - ctrlToCenter.Width) / 2;
ctrlToCenter.Top = (ctrlToCenter.Parent.Height - ctrlToCenter.Height) / 2;

You can put the control you want to center inside a Panel and set the left and right padding values to something larger than the default. As long as they are equal and your control is anchored to the sides of the Panel, then it will appear centered in that Panel. Then you can anchor the container Panel to its parent as needed.

It involves eyeballing it (well I suppose you could get out a calculator and calculate) but just insert said control on the form and then remove any anchoring (anchor = None).

you can put all your controls to panel and then write a code to move your panel to center of your form.
panelMain.Location =
new Point(ClientSize.Width / 2 - panelMain.Size.Width / 2,
ClientSize.Height / 2 - panelMain.Size.Height / 2);
panelMain.Anchor = AnchorStyles.None;

To keep the control centered even the form or parent control were resize.
Set the following properties of the parent element (you can set it through the property window):
parentControl.AutoSize = true;
parentControl.AutoSizeMode = System.Windows.Forms.AutoSizeMode.GrowAndShrink;
Put this code in the Resize event of the form or the parent control (if the control is inside of another control).
controlToCenter.Left = (parentControl.Width- controlToCenter.Width) / 2;
controlToCenter.Top = (parentControl.Height - controlToCenter.Height) / 2;
If the parent control is docked to the form, add this line of code.
//adjust this based on the layout of your form
parentControl.Height = this.ClientSize.Height;

So, I am currently working on a pagination control and I came up with the following to achieve the below result.
Add a PanelLayout to your container (e.g. form or usercontrol)
Set the PanelLayout properties:
Dock: Bottom (or Top)
AutoSize: False
This will center the PanelLayout horizontally.
Now, in your codebehind, do something like this:
public MyConstructor()
{
InitializeComponent();
for (var i = 0; i<10; i++)
{
AddButton(i);
}
}
void AddButton(int i)
{
var btn = new Button();
btn.Width = 30;
btn.Height = 26;
btn.Text = i.ToString();
this.flowLayoutPanel1.Controls.Add(btn);
btn.Anchor = AnchorStyles.None;
}
There is a ceveat, however. If I make my form too small (horizontally) buttons will "disappear" outside of the viewport. In my case, that's not a problem, but you could take care of this by writing code that listens to the Resize event, and remove elements (buttons) based on the viewport Width.