Develop Reference

How to place a label or a button exactly in the middle of the Form?

I can't find tools or properties to place a label or a button exactly in the middle of the Form. For example, on the X axis. VS 2015.

Design time :
In my VisualStudio2010 I have these 2 buttons to center horizontally and vertically:
Its located in the toolbar "Layout". If it isn't, you can add them by clicking the small button to the right. It is also in the Format menu.
To keep centered at Runtime: Turn off all anchoring.
Note:This will keep the control at its relative position as long as it doesn't change it Size. If it does, like autosize Labels are prone to, you will have to code the Resize event. Examples are here

For controls that may change in size, you need to catch the Resize event.
In my case I have a Panel, representing a page, inside another Panel which is the workspace. The workspace is set to autoscroll. In this scenario, it's important that the control is only centered when smaller than the container.
Whenever the form changes size or when I change the content, I call this function:
private void resetPagePos()
{
int wWS = pnlWorkspace.Width;
int hWS = pnlWorkspace.Height;
int wPage = pnlPage.Width;
int hPage = pnlPage.Height;
pnlPage.Location = new Point(Math.Max(0, (wWS - wPage) / 2), pnlPage.Top = Math.Max(0, (hWS - hPage) / 2));
}
The use of Math.Max(0, ...) makes sure that if the item doesn't fit, and the scrollbars are activates, then our page scrolls correctly. If the Left or Top are set to a negative number, you would get unwanted side-effects.

How to determine if control is outside of Form?

I am trying to determine if a dynamically added control is outside of the form.
At first, I thought it might be possible to calculate it by getting the height of the form, and location of the dynamically added control.
But I noticed that the Control.Location and Form.Height have "nothing" in common.
I don't think I really understand what the correlation is between Height and Location.
For example:
I thought that if your form has a height of 500, and I put the control at the bottom of the form, it should give the Location: X, 500 (X is width, not relevant here). But this is not correct, it shows me for example: X, 465. Am I missing something?
So I need to be able to recognize if the control is outside of the form, even if it's just one pixel.
I've found several similar questions here on SO, yet this does not really give me the answer that I need, unfortunately.
So, is there any way to do this? Is it possible to calculate it?

The Height of the form also includes the height of the title bar and borders.
You can use the ClientSize of the form:
From the documentation on MSDN:
The size of the client area of the form is the size of the form excluding the borders and the title bar. The client area of a form is the area within a form where controls can be placed. You can use this property to get the proper dimensions when performing graphics operations or when sizing and positioning controls on the form. To get the size of the entire form, use the Size property or use the individual properties Height and Width.
The position of the control is relative to its container, so (0,0) is the left upper corner inside the form.

I know this is an older thread, but you can try using this method:
public static bool IsOutofBounds(Form form, Control control)
{
int controlEnd_X = control.Location.X + control.ClientSize.Width;
int controlEnd_Y = control.Location.Y + control.ClientSize.Height;
if (form.ClientSize.Width < controlEnd_X || form.ClientSize.Height < controlEnd_Y)
{
return true;
}
else
{
return false;
}
}
It works for checking whether a control is out of bounds of its parent form.

You could use this code to check if controls is inside form:
var Inside = frm.ClientRectange.Intersect(ctrl.Bounds) == ctrl.Bounds;

the top left corner of a form is (0,0) lower right corner is (formHeight, fromWidth).
to check this place two text boxes on a form and write this code in the mouse move event to see how x and y change.
private void Form1_MouseMove(object sender, MouseEventArgs e)
{
textBox1.Text = e.X.ToString();
textBox2.Text = e.Y.ToString();
}
Note that there is an difference between the number returned from the edge of the form and the size chosen by you. In my 500*500 form it is actually 460*483. the difference is always the same for any border style and any resolution.
To place a control on your form use the location structure in the form or use the top and left properties for the control; top = x, left = y.
Remember your offset from the actual height and width you measured and the dimension of the control.
To add a button with the following dimensions 80*30 in the bottom right corner I would right something like this:
button1.Location = new System.Drawing.Point(402, 430);
bottom left corner:
button1.Location = new System.Drawing.Point(0, 430);

GroupBox autosize

Take a GroupBox, put let say Label inside and then set AutoSizeMode = GrowAndShrink and AutoSize = true.
Two problems will arise:
There is a huge gap between Label and bottom of GroupBox (almost enough to fit another Label lol);
AutoSize doesn't respect the GroupBox.Text property.
Question is how to make GroupBox.AutoSize working properly? Properly means: minimum Width should be enough to fit GroupBox.Text, there should be no gaps below for unknown reason (it's not Margin, nor Padding and it looks pretty ugly).
I've tried to measure string length in OnPaint and setting MinimumSize right there. It works, but I have doubts about this, as if I would want to actually set MinimumSize later - it will be lost after repaint.
Update, here is screenshot:

You can get rid of the unwanted yellow space at the bottom by deriving a new class from GroupBox that adjusts the bottom edge a bit. In VB something like ...
Public Class BetterGroupBox
Inherits GroupBox
Public Overrides Function GetPreferredSize(ByVal proposedSize As Size) As Size
Dim ns = MyBase.GetPreferredSize(proposedSize)
Return New Size(ns.Width, ns.Height - 15)
End Function
End Class

It's simple that the location of your Label is fixed at some point other than (0,0), try this:
label1.Location = Point.Empty;
You may also want to try setting the Padding of your GroupBox to 0 for all (default is 3):
groupBox1.Padding = new Padding(0);

It seems as though the GroupBox control has a predefined padding of sorts when growing the control if AutoSize = true. That is, once a control (inside the GroupBox) gets within 20 pixels or so of the bottom of the GroupBox, the GroupBox starts growing. This causes a 20 pixel or so padding from the bottom of the bottom-most control to the bottom of the GroupBox (as highlighted in yellow by #Sinatr's attached image).
Based on my observations, the padding seems to be less when growing the Width of the GroupBox.
At any rate, you can do something like the following "get around" the issue:
public void MyFunction()
{
groupBox1.AutoSize = true;
// Do stuff (e.g., add controls to GroupBox)...
// Once all controls have been added to the GroupBox...
groupBox1.AutoSize = false;
// Add optional padding here if desired.
groupBox1.Height = myBottomMostControl.Bottom;
}

Resize Controls with Form Resize

I have read several stack overflow questions without finding a good working solution to my problem. How can I resize my controls whenever the form is resized? I would like them to get larger or smaller when the form becomes larger or smaller.
In visual basic this was quite easy to do with the form.Zoom property (which did't really require resizing controls of course, but solved what I needed). Unfortunately this is not available in C# winforms.
Here is some other things I have tried without luck:
private void formMain_Resize(object sender, EventArgs e)
{/*
double scale;
this.scaleWidth = (float)this.Width / (float)this.origWidth;
this.scaleHeight = (float)this.Height / (float)this.origHeight;
if (this.scaleHeight > this.scaleWidth)
{
scale = this.scaleHeight;
}
else
{
scale = this.scaleWidth;
}
foreach (Control control in this.Controls)
{
control.Height = (int)(control.Height * this.scaleHeight);
control.Width = (int)(control.Width * this.scaleWidth);
this.Refresh();
// control.Font = new Font("Verdana", control.Font.SizeInPoints * heightRatio * widthRatio);
}
///////This scaling didnt work for me either
//this.Scale(new SizeF(this.scaleWidth, this.scaleHeight));
//this.Refresh();
*/
}
If I overlooked an actualy working sample of code on another stack overflow question I would love to see it, but the ones I found were similar to those above which are not working.
Perhaps I was misusing it and someone could post sample code to show for those of us who keep asking this question how to go about solving the problem.
Also, I have tried using some of the anchor/docking tools thinking they would automatically allow it but it didn't.

The best option is to use a TableLayoutPanel. Put TableLayoutPanel on the form, set the Dock property to Fill, create required rows and columns and put the controls inside the cells. Of course you need to set Dock/Anchor on the controls inside the cells, so they respond to changes to the cell size. In some situations you may need to put a Panel into a cell and drop the controls inside it, because every cell can only contain a single control. You may also need to set RowSpan/ColumnSpan on the controls.
By using a TableLayoutPanel, you have complete control over how your cotrols should be arranged. You can set absolute or percentage size for rows and columns.

Use Anchor of the control. There's an option on anchoring the top, bottom, left and right. And you're good to go.

I found an alternative solution that is working well for me, appreciate any negative or positive comments on the solution.
Using several Split Containers and Split Containers inside of Split Containers in different regions I am able to section off the primary pieces of the layout, and within there utilizing Docking and Anchoring I am able to accomplish exactly what I wanted to do - it works beautifully.
I would point out I am aware that some folks online mention split containers use lots of resources.

If your controls are in a group box, be sure to set the group boxes properties to resize. Controls inside the box are controlled by the box. The box size (unless it is inside another box) is controlled by the form.

What you are trying to do in your code is to change the sizes of the controls which isn't so good approach. Generally, the size of the Buttons and TextBoxes shouldn't be changed when you re-size your form, but they often need to move (change location). Some controls do need to change size according to the re-sized form and but in most cases only one dimension. The central controls that are used for working area (if you are developing the tool for drawing for instance) should change sizes of both dimensions. All this you can accomplish by properly setting Dock and/or Anchor properties of the controls.
textBox1.Dock = DockStyle.Bottom;
textBox1.Anchor = AnchorStyles.Bottom & AnchorStyles.Left;
All these are also easily set in the Properties panel when using designer.
But if that isn't enough for you, in rare cases, you will most definitely want to only change the location of the control:
textBox1.Location = new Point(newX, newY);

Windows mobile autoresize with panels

I've got an app which will run on two different devices - one with a screen size of 240x320, the other 480x640.
For all forms bar one the VS generated code is fine:
this.AutoScaleDimensions = new System.Drawing.SizeF(96F, 96F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Dpi;
this.AutoScroll = true;
For one form i'm capturing a signature. I'm doing this by a panel with a graphics handler; capturing mouse down and move events; this generates a list of vector points which I can draw lines with.
On the smaller res screen this is fine. On the higher res, I can't display my lines.. and I think this is because the panel is beyond the windows form size.
The form is created with a size of 240 x 268; a standard size I think - i've not manually set it, VS does this for me.
In order to get the panel in the right spot on the high res device, the co-ordinates are 3, 290; ie, 290 is past 268. Also the width of the panel is 448 which is somewhat larger than 240.
I'm using .net 2.0 (can't use later). I think I need to resize the form to make it larger but I do want to keep the existing re-sizing for the other controls on the form.
I'm not sure how to do this.

Make the form dock to fill, then use the Anchor properties to ensure controls inside the form resize as expected.
If you want the option of customizing how an individual control resizes, then DONT set the anchor properties on it, and instead handle the Resize event and perform custom resizing/repositioning within code there.
eg
private void form_Resize(object sender, EventArgs e)
{
// Center the control without changing width. Other controls are anchored.
this.control.Left = (this.Width - this.control.Width) / 2;
}

I'm writing this answer for the benefit of those who may have a similar problem in the future. PaulG pointed me in the right direction but I found the root cause to be something else.
The PDA project i've got uses "FormFactor WindowsMobile 6 Classic" which has a default size of 240 x 268.
Changing this to "Windows Mobile 6 Professional VGA" created a much larger form size.
This allowed me to get things positioned correctly for the larger size; then AutoScaleMode to DPI; and manually resizing the panel smaller made it all work.
IE, going from larger to smaller was easy; I didn't get smaller to larger working.