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Auto resizing items/controls in winforms c# showing error

I've been trying to make my windows form application auto resizing i.e. when the user resizes the application its controls also resize accordingly and after searching online I've come across the below code in the form of a .cs file :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
public class clsResize
{
List<System.Drawing.Rectangle> _arr_control_storage = new List<System.Drawing.Rectangle>();
private bool showRowHeader = false;
public clsResize(Form _form_)
{
form = _form_; //the calling form
_formSize = _form_.ClientSize; //Save initial form size
_fontsize = _form_.Font.Size; //Font size
}
private float _fontsize { get; set; }
private System.Drawing.SizeF _formSize {get;set; }
private Form form { get; set; }
public void _get_initial_size() //get initial size//
{
var _controls = _get_all_controls(form);//call the enumerator
foreach (Control control in _controls) //Loop through the controls
{
_arr_control_storage.Add(control.Bounds); //saves control bounds/dimension
//If you have datagridview
if (control.GetType() == typeof(DataGridView))
_dgv_Column_Adjust(((DataGridView)control), showRowHeader);
}
}
public void _resize() //Set the resize
{
double _form_ratio_width = (double)form.ClientSize.Width /(double)_formSize.Width; //ratio could be greater or less than 1
double _form_ratio_height = (double)form.ClientSize.Height / (double)_formSize.Height; // this one too
var _controls = _get_all_controls(form); //reenumerate the control collection
int _pos = -1;//do not change this value unless you know what you are doing
foreach (Control control in _controls)
{
// do some math calc
_pos += 1;//increment by 1;
System.Drawing.Size _controlSize = new System.Drawing.Size((int)(_arr_control_storage[_pos].Width * _form_ratio_width),
(int)(_arr_control_storage[_pos].Height * _form_ratio_height)); //use for sizing
System.Drawing.Point _controlposition = new System.Drawing.Point((int)
(_arr_control_storage[_pos].X * _form_ratio_width),(int) (_arr_control_storage[_pos].Y * _form_ratio_height));//use for location
//set bounds
control.Bounds = new System.Drawing.Rectangle(_controlposition, _controlSize); //Put together
//Assuming you have a datagridview inside a form()
//if you want to show the row header, replace the false statement of
//showRowHeader on top/public declaration to true;
if (control.GetType() == typeof(DataGridView))
_dgv_Column_Adjust(((DataGridView)control), showRowHeader);
//Font AutoSize
control.Font = new System.Drawing.Font(form.Font.FontFamily,
(float)(((Convert.ToDouble(_fontsize) * _form_ratio_width) / 2) +
((Convert.ToDouble(_fontsize) * _form_ratio_height) / 2)));
}
}
private void _dgv_Column_Adjust(DataGridView dgv, bool _showRowHeader) //if you have Datagridview
//and want to resize the column base on its dimension.
{
int intRowHeader = 0;
const int Hscrollbarwidth = 5;
if (_showRowHeader)
intRowHeader = dgv.RowHeadersWidth;
else
dgv.RowHeadersVisible = false;
for (int i = 0; i < dgv.ColumnCount; i++)
{
if (dgv.Dock == DockStyle.Fill) //in case the datagridview is docked
dgv.Columns[i].Width = ((dgv.Width - intRowHeader) / dgv.ColumnCount);
else
dgv.Columns[i].Width = ((dgv.Width - intRowHeader - Hscrollbarwidth) / dgv.ColumnCount);
}
}
private static IEnumerable<Control> _get_all_controls(Control c)
{
return c.Controls.Cast<Control>().SelectMany(item =>
_get_all_controls(item)).Concat(c.Controls.Cast<Control>()).Where(control =>
control.Name != string.Empty);
}
}
I added this to my project used in code as below :
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
namespace KryptonTest
{
/// <summary>
/// Description of MainForm.
/// </summary>
public partial class MainForm : KryptonForm
{
clsResize _form_resize;
public MainForm()
{
//
// The InitializeComponent() call is required for Windows Forms designer support.
//
InitializeComponent();
_form_resize = new clsResize(this);
this.Load += MainFormLoad;
this.Resize += MainFormResize;
}
void MainFormLoad(object sender, EventArgs e)
{
_form_resize._get_initial_size();
}
void MainFormResize(object sender, EventArgs e)
{
_form_resize._resize();
}
}
}
But when I run it I get the below error twice
How do I fix this?

When we resize a form we normally pick some controls to get bigger and others not - it doesn't really make much sense to double the width and height of a name TextBox, or a Checkbox because you don't type/see significantly more text in them. Other items like a logging list box, email body designer TextBox etc, it makes sense to have those things resize.
Arranging a layout that resizes is quite simple: every control has an Anchor property and when the anchor for a particular side is set then the control will move or resize so there is the same distance between the control and the given edge of the container. Obviously then if a control is anchored on opposing sides, then it will stretch when the container it is in gets bigger
Some examples:
TextBox is 100 wide and 20 high, anchored on Top Left. The form is made 200 pixels wider and 200 higher. The TextBox appears not to move or grow; it remains the same distance from the top left corner
TextBox is 100 wide and 20 high, anchored on Top Right. The form is made 200 pixels wider and 200 higher. The TextBox moves 200 pixels to the Right because it is Right anchored and keeps the same distance between the form right edge. It does not grow wider; it remains the same distance from the top left corner. It does not grow taller because it is Top anchored but not Bottom anchored
TextBox is 100 wide and 20 high, anchored on Top Left Bottom Right. It is a multi line TextBox. The form is made 200 pixels wider and 200 higher. The TextBox grows 200 pixels wider and 200 pixels higher because the form has grown by 200x200 - the anchors on all sides means the textbox edges stay the same distance from the form edges
You want 3 textboxes in a row, the middle one should get wider when the form gets wider; the other two textboxes should not grow
You anchor the left TextBox on the Top Left
You anchor the middle TextBox on Top Left Right
You anchor the right TextBox on the Top Right
When the form gets wider the left TextBox stays put, the right TextBox moves to the right by as much as the form got wider, the middle TextBox expands sideways by as much as the form got wider
When neither opposing side is anchored the control moves by half the distance of the resize in that direction
Don't forget you can put panels in that are anchored one way and then controls inside them that are anchored another way. For other kinds of layouts you might need a table or flow layout panel but for most UIs the anchoring system works quite well

Are you sure the enum is working properly? The error message is telling you the list has less items than you're trying to call.
Index was out of range. Must be non-negative and less than the size
of the collection. Parameter name: index
Edit:
I just copied and pasted your code into a new WinForms project in VS 2022 and it worked with no issues though I did have to drop the inheritance reference to KryptonForm since I didn't have it. If it helps, I ran it using .Net 6.0 (LTS)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WinFormsApp1
{
/// <summary>
/// Description of MainForm.
/// </summary>
public partial class MainForm : Form
{
clsResize _form_resize;
public MainForm()
{
InitializeComponent();
_form_resize = new clsResize(this);
this.Load += MainFormLoad;
this.Resize += MainFormResize;
}
void MainFormLoad(object sender, EventArgs e)
{
_form_resize._get_initial_size();
}
void MainFormResize(object sender, EventArgs e)
{
_form_resize._resize();
}
}
public class clsResize
{
List<System.Drawing.Rectangle> _arr_control_storage = new List<System.Drawing.Rectangle>();
private bool showRowHeader = false;
public clsResize(Form _form_)
{
form = _form_; //the calling form
_formSize = _form_.ClientSize; //Save initial form size
_fontsize = _form_.Font.Size; //Font size
}
private float _fontsize { get; set; }
private System.Drawing.SizeF _formSize { get; set; }
private Form form { get; set; }
public void _get_initial_size() //get initial size//
{
var _controls = _get_all_controls(form);//call the enumerator
foreach (Control control in _controls) //Loop through the controls
{
_arr_control_storage.Add(control.Bounds); //saves control bounds/dimension
//If you have datagridview
if (control.GetType() == typeof(DataGridView))
_dgv_Column_Adjust(((DataGridView)control), showRowHeader);
}
}
public void _resize() //Set the resize
{
double _form_ratio_width = (double)form.ClientSize.Width / (double)_formSize.Width; //ratio could be greater or less than 1
double _form_ratio_height = (double)form.ClientSize.Height / (double)_formSize.Height; // this one too
var _controls = _get_all_controls(form); //reenumerate the control collection
int _pos = -1;//do not change this value unless you know what you are doing
foreach (Control control in _controls)
{
// do some math calc
_pos += 1;//increment by 1;
System.Drawing.Size _controlSize = new System.Drawing.Size((int)(_arr_control_storage[_pos].Width * _form_ratio_width),
(int)(_arr_control_storage[_pos].Height * _form_ratio_height)); //use for sizing
System.Drawing.Point _controlposition = new System.Drawing.Point((int)
(_arr_control_storage[_pos].X * _form_ratio_width), (int)(_arr_control_storage[_pos].Y * _form_ratio_height));//use for location
//set bounds
control.Bounds = new System.Drawing.Rectangle(_controlposition, _controlSize); //Put together
//Assuming you have a datagridview inside a form()
//if you want to show the row header, replace the false statement of
//showRowHeader on top/public declaration to true;
if (control.GetType() == typeof(DataGridView))
_dgv_Column_Adjust(((DataGridView)control), showRowHeader);
//Font AutoSize
control.Font = new System.Drawing.Font(form.Font.FontFamily,
(float)(((Convert.ToDouble(_fontsize) * _form_ratio_width) / 2) +
((Convert.ToDouble(_fontsize) * _form_ratio_height) / 2)));
}
}
private void _dgv_Column_Adjust(DataGridView dgv, bool _showRowHeader) //if you have Datagridview
//and want to resize the column base on its dimension.
{
int intRowHeader = 0;
const int Hscrollbarwidth = 5;
if (_showRowHeader)
intRowHeader = dgv.RowHeadersWidth;
else
dgv.RowHeadersVisible = false;
for (int i = 0; i < dgv.ColumnCount; i++)
{
if (dgv.Dock == DockStyle.Fill) //in case the datagridview is docked
dgv.Columns[i].Width = ((dgv.Width - intRowHeader) / dgv.ColumnCount);
else
dgv.Columns[i].Width = ((dgv.Width - intRowHeader - Hscrollbarwidth) / dgv.ColumnCount);
}
}
private static IEnumerable<Control> _get_all_controls(Control c)
{
return c.Controls.Cast<Control>().SelectMany(item =>
_get_all_controls(item)).Concat(c.Controls.Cast<Control>()).Where(control =>
control.Name != string.Empty);
}
}
}

Size adjustments for Panel control in windows forms

I have a Panel control on my winform which will display multiple panels inside that. For each inner panel I am setting its height. But some has less content to display some has more.
Panel hrvPanel = new Panel();
ArrayList hrvColl = pnlColl ; //Panel collection list gets from a Method
if(hrvColl.Count == 0)
return;
int splits = 0;
for(int p= hrvColl.Count-1;p>=0;p--)
{
Panel hrv = hrvColl[p] as Panel;
hrv.Height = 150;
hrvPanel.Controls.Add(hrv);
//Adding splliter
if(splits < hrvColl.Count - 1)
{
Splitter splitGrid = new Splitter();
splitGrid.Dock = DockStyle.Top;
hrvPanel.Controls.Add(splitGrid);
splits++;
}
}
hrvPanel.Dock = DockStyle.Top;
How to adjust the height of each inner panel based on its content size? I tried setting hrv.AutoSize to true,then I can see only the last panel And hrv.Dock = Top but the result is same.

If the outer Panel has Autosize = true you will be able to see all inner Panels. Promise.
If you don't, you have got some settings wrong. Make sure no unwanted settings of Dock and Anchor are used in the inner Panels.
It is also very simple to write code to find out the maximum of Top + Height over all inner Panels:
int max = 0;
foreach (Control ctl in panelOuter.Controls)
if (ctl.Top + ctl.Height > max) max = ctl.Top + ctl.Height;
panelOuter.Height = max + 3; // add the default margin!
This may be useful if you only want to set the Height and leave the Width as it is..other than that: The AutoSize property will do its job!

This is where WPF overcomes Winform, you probably can't do this automatically in Winforms. But you may have a work around like this-
Create an extended panel class that should know its preferred height
class ExPanel : Panel
{
public int PreferredHeight
{
get;
private set;
}
public ExPanel(int preferredHeight)
: base()
{
PreferredHeight = preferredHeight;
}
}
and then you can use this class as-
ExPanel hrvPanel = new ExPanel(150);
System.Collections.ArrayList hrvColl = pnlColl; //Panel collection list gets from a Method
if (hrvColl.Count == 0)
return;
int splits = 0;
for (int p = hrvColl.Count - 1; p >= 0; p--)
{
ExPanel hrv = hrvColl[p] as ExPanel;
hrv.Height = hrv.PreferredHeight;
hrvPanel.Controls.Add(hrv);
//Adding splliter
if (splits < hrvColl.Count - 1)
{
Splitter splitGrid = new Splitter();
splitGrid.Dock = DockStyle.Top;
hrvPanel.Controls.Add(splitGrid);
splits++;
}
}
hrvPanel.Dock = DockStyle.Top;
it's just an workaround to achieve your target, if you don't want to manage the height for your every panel.

How can a scrollable area retrieve the size of what is being displayed?

In my application I've got the following situation:
I've got a Windows Form with a Tab Control with several tabs. Each tab contains arbitrary content which is added by other classes upon startup or during runtime.
I want to set up the tabs in a way that scrollbars appear automatically as soon as the Form is too small for the tab's panel to display everything.
What I've tried so far is setting the tab page's AutoScroll = true and setting the AutoScrollMinSize property to the size of the panel.
This did not work as expected as the panel's Size always seems to be (200, 100) independent of its contents.
I've created a small example application (code below) which demonstrates the issue. If you resize the form, you'll see that scroll bars only appear if the Form gets smaller than the panel (default size of (200, 100)) rather than the text box in the panel (size of 300, 150). If you set AutoScrollMinSize manually (uncomment line 34), it behaves as expected.
The question is: How can the tab page retrieve the actual size of what is displayed in it?
I could probably recurse through all controls and try calculating the size myself - but this feels really bad.
PS: Please do not suggest setting the size of the panel to the size of the label, as the actual panels are much more complex than that. ;-)
Code:
Simply create an Application in Visual Studio and override Program.cs with the following code:
using System;
using System.Windows.Forms;
namespace ScrollbarTest
{
static class Program
{
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
var sampleForm = CreateSampleForm();
Application.Run(sampleForm);
}
private static Form CreateSampleForm()
{
var sampleForm = new Form() { };
var tabControl = new TabControl() { Dock = DockStyle.Fill };
var tabPage = new TabPage("Test") { AutoScroll = true };
sampleForm.Controls.Add(tabControl);
tabControl.TabPages.Add(tabPage);
var samplePanel = CreateSamplePanel();
tabPage.Controls.Add(samplePanel);
// this does not provide the right size
tabPage.AutoScrollMinSize = samplePanel.Size;
// uncomment this to make it work
//tabPage.AutoScrollMinSize = new System.Drawing.Size(300, 150);
return sampleForm;
}
private static Control CreateSamplePanel()
{
// As an example, create a panel with a text box with a fixed size.
var samplePanel = new Panel() { Dock = DockStyle.Fill };
var sampleSize = new System.Drawing.Size(300, 150);
var textBox = new TextBox()
{
Dock = DockStyle.Fill,
MinimumSize = sampleSize,
MaximumSize = sampleSize,
Size = sampleSize
};
samplePanel.Controls.Add(textBox);
return samplePanel;
}
}
}

The samplePanel.Size returns (200,100). In your CreateSamplePanel method, if you set samplePanel.MinimumSize = sampleSize; then your code will work.
Panels don't calculate their size properties (e.g. Size, MinimumSize, PreferredSize) based on their child controls. You will have to subclass Panel and provide that behavior. Even TableLayoutPanel and FlowLayoutPanel don't correctly calculate the PreferredSize property, which is surprising. At the very least, normally you override the GetPreferredSize(Size proposedSize) method, and optionally have the MinimumSize property return the PreferredSize property.
It's worth noting that DockStyle.Fill and MinimumSize are at odds with each other. TabPage controls are inherently DockStyle.Fill mode, which is why you have to set the AutoScrollMinSize property.
Edit: Isn't there any existing function which retrieves the total required size of a list of controls (recursively), e.g. through their X/Y and Size?
It's up to the host container itself (e.g. TableLayoutPanel) to calculate its PreferredSize correctly because only it knows the exact details of how its layout is performed.
You can set the AutoSize property to true and then hope that GetPreferredSize(...)/PreferredSize calculates the right size. For TableLayoutPanel, I recall there was a case where it wasn't calculating correctly and I had to subclass it and override the GetPreferredSize(...) method. GetPreferredSize(...) won't be called unless AutoSize is true.
If you're talking about a plain Panel or UserControl, by default these use the WYSIWYG LayoutEngine, and do not calculate the PreferredSize. You could subclass and then calculate maximum control.X + control.Width and same thing for height, and use that as the preferred size.
First try setting AutoSize to true and see if that works for you. If not, you might have to override the GetPreferredSize(...) method. Here is a crude example:
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
var sampleForm = new Form() { AutoScroll = true };
var panel = new MyPanel() { AutoSize = true, AutoSizeMode = AutoSizeMode.GrowAndShrink, BackColor = Color.LightYellow };
for (int i = 0; i < 6; i++) {
for (int j = 0; j < 3; j++) {
Button b = new Button { Text = "Button" + panel.Controls.Count, AutoSize = true };
b.Click += delegate {
MessageBox.Show("Preferred Size: " + panel.PreferredSize);
};
panel.Controls.Add(b, j, i);
}
}
sampleForm.Controls.Add(panel);
Application.Run(sampleForm);
}
private class MyPanel : TableLayoutPanel {
public override Size MinimumSize {
get {
return PreferredSize;
}
set {
}
}
public override Size GetPreferredSize(Size proposedSize) {
Size s = new Size();
int[] harr = new int[100];//this.RowCount];
int[] warr = new int[100];//this.ColumnCount];
foreach (Control c in this.Controls) {
var cell = this.GetPositionFromControl(c);
var ps = c.PreferredSize;
Padding m = c.Margin;
int w = ps.Width + m.Horizontal;
int h = ps.Height + m.Vertical;
if (w > warr[cell.Column])
warr[cell.Column] = w;
if (h > harr[cell.Row])
harr[cell.Row] = h;
}
foreach (int w in warr)
s.Width += w;
foreach (int h in harr)
s.Height += h;
return s;
}
}

How can I instantiate large number of buttons in Windows Forms?

I'm developing a theatre reservation software. I'm using Windows Forms, the seats is represented by a 2-dimensioned array. And I draw the buttons as following:
public void DrawSeats()
{
// pnl_seats is a Panel
pnl_seats.Controls.Clear();
// Here I store all Buttons instance, to later add all buttons in one call (AddRange) to the Panel
var btns = new List<Control>();
// Suspend layout to avoid undesired Redraw/Refresh
this.SuspendLayout();
for (int y = 0; y < _seatZone.VerticalSize; y++)
{
for (int x = 0; x < _seatZone.HorizontalSize; x++)
{
// Check if this seat exists
if (IsException(x, y))
continue;
// Construct the button with desired properties. SeatSize is a common value for every button
var btn = new Button
{
Width = SeatSize,
Height = SeatSize,
Left = (x * SeatSize),
Top = (y * SeatSize),
Text = y + "" + x,
Tag = y + ";" + x, // When the button clicks, the purpose of this is to remember which seat this button is.
Font = new Font(new FontFamily("Microsoft Sans Serif"), 6.5f)
};
// Check if it is already reserved
if (ExistsReservation(x, y))
btn.Enabled = false;
else
btn.Click += btn_seat_Click; // Add click event
btns.Add(btn);
}
}
// As said before, add all buttons in one call
pnl_seats.Controls.AddRange(btns.ToArray());
// Resume the layout
this.ResumeLayout();
}
But already with a seat zone of 20 by 20 (400 buttons), it spent almost 1 minute to draw it, and in debug I checked that the lack of performance, is the instantiation of the buttons.
There is a way to make it faster? Perhaps disable all events during the instatiation or another lightweight Control that has the Click event too?
UPDATE:
lbl was a test, the correct is btn, sorry.
UPDATE 2:
Here is the IsException and ExistsReservations methods:
private bool IsException(int x, int y)
{
for (var k = 0; k < _seatsExceptions.GetLength(0); k++)
if (_seatsExceptions[k, 0] == x && _seatsExceptions[k, 1] == y)
return true;
return false;
}
private bool ExistsReservation(int x, int y)
{
for (var k = 0; k < _seatsReservations.GetLength(0); k++)
if (_seatsReservations[k, 0] == x && _seatsReservations[k, 1] == y)
return true;
return false;
}

Suppose that you change your arrays for reservations and exclusions to
public List<string> _seatsExceptions = new List<string>();
public List<string> _seatsReservations = new List<string>();
you add your exclusions and reservations in the list with something like
_seatsExceptions.Add("1;10");
_seatsExceptions.Add("4;19");
_seatsReservations.Add("2;5");
_seatsReservations.Add("5;5");
your checks for exclusions and reservations could be changed to
bool IsException(int x, int y)
{
string key = x.ToString() + ";" + y.ToString();
return _seatsExceptions.Contains(key);
}
bool ExistsReservation(int x, int y)
{
string key = x.ToString() + ";" + y.ToString();
return _seatsReservations.Contains(key);
}
of course I don't know if you are able to make this change or not in your program. However consider to change the search on your array sooner or later.
EDIT I have made some tests, and while a virtual grid of 20x20 buttons works acceptably well (31 millisecs 0.775ms on average), a bigger one slows down noticeably. At 200x50 the timing jumps to 10 seconds (1,0675 on average). So perhaps a different approach is needed. A bound DataGridView could be a simpler solution and will be relatively easy to handle.

I also won't use such a myriad of controls to implement such a thing. Instead you should maybe create your own UserControl, which will paint all the seats as images and reacts on a click event.
To make it a little easier for you i created such a simple UserControl, that will draw all the seats and reacts on a mouse click for changing of the state. Here it is:
public enum SeatState
{
Empty,
Selected,
Full
}
public partial class Seats : UserControl
{
private int _Columns;
private int _Rows;
private List<List<SeatState>> _SeatStates;
public Seats()
{
InitializeComponent();
this.DoubleBuffered = true;
_SeatStates = new List<List<SeatState>>();
_Rows = 40;
_Columns = 40;
ReDimSeatStates();
MouseUp += OnMouseUp;
Paint += OnPaint;
Resize += OnResize;
}
public int Columns
{
get { return _Columns; }
set
{
_Columns = Math.Min(1, value);
ReDimSeatStates();
}
}
public int Rows
{
get { return _Rows; }
set
{
_Rows = Math.Min(1, value);
ReDimSeatStates();
}
}
private Image GetPictureForSeat(int row, int column)
{
var seatState = _SeatStates[row][column];
switch (seatState)
{
case SeatState.Empty:
return Properties.Resources.emptySeat;
case SeatState.Selected:
return Properties.Resources.choosenSeat;
default:
case SeatState.Full:
return Properties.Resources.fullSeat;
}
}
private void OnMouseUp(object sender, MouseEventArgs e)
{
var heightPerSeat = Height / (float)Rows;
var widthPerSeat = Width / (float)Columns;
var row = (int)(e.X / widthPerSeat);
var column = (int)(e.Y / heightPerSeat);
var seatState = _SeatStates[row][column];
switch (seatState)
{
case SeatState.Empty:
_SeatStates[row][column] = SeatState.Selected;
break;
case SeatState.Selected:
_SeatStates[row][column] = SeatState.Empty;
break;
}
Invalidate();
}
private void OnPaint(object sender, PaintEventArgs e)
{
var heightPerSeat = Height / (float)Rows;
var widthPerSeat = Width / (float)Columns;
e.Graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
e.Graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
e.Graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
for (int row = 0; row < Rows; row++)
{
for (int column = 0; column < Columns; column++)
{
var seatImage = GetPictureForSeat(row, column);
e.Graphics.DrawImage(seatImage, row * widthPerSeat, column * heightPerSeat, widthPerSeat, heightPerSeat);
}
}
}
private void OnResize(object sender, System.EventArgs e)
{
Invalidate();
}
private void ReDimSeatStates()
{
while (_SeatStates.Count < Rows)
_SeatStates.Add(new List<SeatState>());
if (_SeatStates.First().Count < Columns)
foreach (var columnList in _SeatStates)
while (columnList.Count < Columns)
columnList.Add(SeatState.Empty);
while (_SeatStates.Count > Rows)
_SeatStates.RemoveAt(_SeatStates.Count - 1);
if (_SeatStates.First().Count > Columns)
foreach (var columnList in _SeatStates)
while (columnList.Count > Columns)
columnList.RemoveAt(columnList.Count - 1);
}
}
This will currently draw forty rows and columns (so there are 800 seats) and you can click on each seat to change its state.
Here are the images i used:
EmtpySeat:
ChoosenSeat:
FullSeat:
If you anchor this control and resize it or you click on a seat to change its state there can be some minor lacking for the repainting if you further increase the number of rows or columns, but that is still somewhere far below one second. If this still hurts you, you have to improve the paint method and maybe check the ClipRectangle property of the paint event and only paint the really needed parts, but that's another story.

Rather than using actual button controls, just draw the image of the seats then when the user clicks on a seat translate the mouse X,Y coordinates to determine which seat was clicked. This will be more efficient. Of course, the drawback is that you have to write the method to translate x,y coordinates to a seat, but that really isn't that difficult.

EDIT; it has been pointed out to me this will not work in Windows Forms!
Well, you are Sequentially working through it.
if one iteration costs 1 sec, the full process will take 400*1 in time.
Perhaps you should try and make a collection of your objects, and process it 'parallel'.
try the .Net framework (4 and above) 'parallel foreach' method:
http://msdn.microsoft.com/en-s/library/system.threading.tasks.parallel.foreach(v=vs.110).aspx
edit: so, if you have a list buttonnames, you can say
buttonNames.ForEach(x=>CreateButton(x));
while your CreateButton() method is as following:
private Button CreateButton(string nameOfButton) { Button b = new
Button(); b.Text = nameOfButton; //do whatever you want...
return b; }

Handle scrolling of a WinForms control manually

I have a control (System.Windows.Forms.ScrollableControl) which can potentially be very large. It has custom OnPaint logic. For that reason, I am using the workaround described here.
public class CustomControl : ScrollableControl
{
public CustomControl()
{
this.AutoScrollMinSize = new Size(100000, 500);
this.DoubleBuffered = true;
}
protected override void OnScroll(ScrollEventArgs se)
{
base.OnScroll(se);
this.Invalidate();
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
var graphics = e.Graphics;
graphics.Clear(this.BackColor);
...
}
}
The painting code mainly draws "normal" things that move when you scroll. The origin of each shape that is drawn is offsetted by this.AutoScrollPosition.
graphics.DrawRectangle(pen, 100 + this.AutoScrollPosition.X, ...);
However, the control also contains "static" elements, which are always drawn at the same position relative to the parent control. For that, I just don't use AutoScrollPosition and draw the shapes directly:
graphics.DrawRectangle(pen, 100, ...);
When the user scrolls, Windows translates the entire visible area in the direction opposite to the scrolling. Usually this makes sense, because then the scrolling seems smooth and responsive (and only the new part has to be redrawn), however the static parts are also affected by this translation (hence the this.Invalidate() in OnScroll). Until the next OnPaint call has successfully redrawn the surface, the static parts are slightly off. This causes a very noticable "shaking" effect when scrolling.
Is there a way I can create a scrollable custom control that does not have this problem with static parts?

You could do this by taking full control of scrolling. At the moment, you're just hooking in to the event to do your logic. I've faced issues with scrolling before, and the only way I've ever managed to get everything to work smoothly is by actually handling the Windows messages by overriding WndProc. For instance, I have this code to synchronize scrolling between several ListBoxes:
protected override void WndProc(ref Message m) {
base.WndProc(ref m);
// 0x115 and 0x20a both tell the control to scroll. If either one comes
// through, you can handle the scrolling before any repaints take place
if (m.Msg == 0x115 || m.Msg == 0x20a)
{
//Do you scroll processing
}
}
Using WndProc will get you the scroll messages before anything gets repainted at all, so you can appropriately handle the static objects. I'd use this to suspend scrolling until an OnPaint occurs. It won't look as smooth, but you won't have issues with the static objects moving.

Since I really needed this, I ended up writing a Control specifically for the case when you have static graphics on a scrollable surface (whose size can be greater than 65535).
It is a regular Control with two ScrollBar controls on it, and a user-assignable Control as its Content. When the user scrolls, the container sets its Content's AutoScrollOffset accordingly. Therefore, it is possible to use controls which use the AutoScrollOffset method for drawing without changing anything. The Content's actual size is exactly the visible part of it at all times. It allows horizontal scrolling by holding down the shift key.
Usage:
var container = new ManuallyScrollableContainer();
var content = new ExampleContent();
container.Content = content;
container.TotalContentWidth = 150000;
container.TotalContentHeight = 5000;
container.Dock = DockStyle.Fill;
this.Controls.Add(container); // e.g. add to Form
Code:
It became a bit lengthy, but I could avoid ugly hacks. Should work with mono. I think it turned out pretty sane.
public class ManuallyScrollableContainer : Control
{
public ManuallyScrollableContainer()
{
InitializeControls();
}
private class UpdatingHScrollBar : HScrollBar
{
protected override void OnValueChanged(EventArgs e)
{
base.OnValueChanged(e);
// setting the scroll position programmatically shall raise Scroll
this.OnScroll(new ScrollEventArgs(ScrollEventType.EndScroll, this.Value));
}
}
private class UpdatingVScrollBar : VScrollBar
{
protected override void OnValueChanged(EventArgs e)
{
base.OnValueChanged(e);
// setting the scroll position programmatically shall raise Scroll
this.OnScroll(new ScrollEventArgs(ScrollEventType.EndScroll, this.Value));
}
}
private ScrollBar shScrollBar;
private ScrollBar svScrollBar;
public ScrollBar HScrollBar
{
get { return this.shScrollBar; }
}
public ScrollBar VScrollBar
{
get { return this.svScrollBar; }
}
private void InitializeControls()
{
this.Width = 300;
this.Height = 300;
this.shScrollBar = new UpdatingHScrollBar();
this.shScrollBar.Top = this.Height - this.shScrollBar.Height;
this.shScrollBar.Left = 0;
this.shScrollBar.Anchor = AnchorStyles.Bottom | AnchorStyles.Left | AnchorStyles.Right;
this.svScrollBar = new UpdatingVScrollBar();
this.svScrollBar.Top = 0;
this.svScrollBar.Left = this.Width - this.svScrollBar.Width;
this.svScrollBar.Anchor = AnchorStyles.Right | AnchorStyles.Top | AnchorStyles.Bottom;
this.shScrollBar.Width = this.Width - this.svScrollBar.Width;
this.svScrollBar.Height = this.Height - this.shScrollBar.Height;
this.Controls.Add(this.shScrollBar);
this.Controls.Add(this.svScrollBar);
this.shScrollBar.Scroll += this.HandleScrollBarScroll;
this.svScrollBar.Scroll += this.HandleScrollBarScroll;
}
private Control _content;
/// <summary>
/// Specifies the control that should be displayed in this container.
/// </summary>
public Control Content
{
get { return this._content; }
set
{
if (_content != value)
{
RemoveContent();
this._content = value;
AddContent();
}
}
}
private void AddContent()
{
if (this.Content != null)
{
this.Content.Left = 0;
this.Content.Top = 0;
this.Content.Width = this.Width - this.svScrollBar.Width;
this.Content.Height = this.Height - this.shScrollBar.Height;
this.Content.Anchor = AnchorStyles.Bottom | AnchorStyles.Left | AnchorStyles.Top | AnchorStyles.Right;
this.Controls.Add(this.Content);
CalculateMinMax();
}
}
private void RemoveContent()
{
if (this.Content != null)
{
this.Controls.Remove(this.Content);
}
}
protected override void OnParentChanged(EventArgs e)
{
// mouse wheel events only arrive at the parent control
if (this.Parent != null)
{
this.Parent.MouseWheel -= this.HandleMouseWheel;
}
base.OnParentChanged(e);
if (this.Parent != null)
{
this.Parent.MouseWheel += this.HandleMouseWheel;
}
}
private void HandleMouseWheel(object sender, MouseEventArgs e)
{
this.HandleMouseWheel(e);
}
/// <summary>
/// Specifies how the control reacts to mouse wheel events.
/// Can be overridden to adjust the scroll speed with the mouse wheel.
/// </summary>
protected virtual void HandleMouseWheel(MouseEventArgs e)
{
// The scroll difference is calculated so that with the default system setting
// of 3 lines per scroll incremenet,
// one scroll will offset the scroll bar value by LargeChange / 4
// i.e. a quarter of the thumb size
ScrollBar scrollBar;
if ((Control.ModifierKeys & Keys.Shift) != 0)
{
scrollBar = this.HScrollBar;
}
else
{
scrollBar = this.VScrollBar;
}
var minimum = 0;
var maximum = scrollBar.Maximum - scrollBar.LargeChange;
if (maximum <= 0)
{
// happens when the entire area is visible
return;
}
var value = scrollBar.Value - (int)(e.Delta * scrollBar.LargeChange / (120.0 * 12.0 / SystemInformation.MouseWheelScrollLines));
scrollBar.Value = Math.Min(Math.Max(value, minimum), maximum);
}
public event ScrollEventHandler Scroll;
protected virtual void OnScroll(ScrollEventArgs e)
{
var handler = this.Scroll;
if (handler != null)
{
handler(this, e);
}
}
/// <summary>
/// Event handler for the Scroll event of either scroll bar.
/// </summary>
private void HandleScrollBarScroll(object sender, ScrollEventArgs e)
{
OnScroll(e);
if (this.Content != null)
{
this.Content.AutoScrollOffset = new System.Drawing.Point(-this.HScrollBar.Value, -this.VScrollBar.Value);
this.Content.Invalidate();
}
}
private int _totalContentWidth;
public int TotalContentWidth
{
get { return _totalContentWidth; }
set
{
if (_totalContentWidth != value)
{
_totalContentWidth = value;
CalculateMinMax();
}
}
}
private int _totalContentHeight;
public int TotalContentHeight
{
get { return _totalContentHeight; }
set
{
if (_totalContentHeight != value)
{
_totalContentHeight = value;
CalculateMinMax();
}
}
}
protected override void OnResize(EventArgs e)
{
base.OnResize(e);
CalculateMinMax();
}
private void CalculateMinMax()
{
if (this.Content != null)
{
// Reduced formula according to
// http://msdn.microsoft.com/en-us/library/system.windows.forms.scrollbar.maximum.aspx
// Note: The original formula is bogus.
// According to the article, LargeChange has to be known in order to calculate Maximum,
// however, that is not always possible because LargeChange cannot exceed Maximum.
// If (LargeChange) == (1 * visible part of control), the formula can be reduced to:
if (this.TotalContentWidth > this.Content.Width)
{
this.shScrollBar.Enabled = true;
this.shScrollBar.Maximum = this.TotalContentWidth;
}
else
{
this.shScrollBar.Enabled = false;
}
if (this.TotalContentHeight > this.Content.Height)
{
this.svScrollBar.Enabled = true;
this.svScrollBar.Maximum = this.TotalContentHeight;
}
else
{
this.svScrollBar.Enabled = false;
}
// this must be set after the maximum is determined
this.shScrollBar.LargeChange = this.shScrollBar.Width;
this.shScrollBar.SmallChange = this.shScrollBar.LargeChange / 10;
this.svScrollBar.LargeChange = this.svScrollBar.Height;
this.svScrollBar.SmallChange = this.svScrollBar.LargeChange / 10;
}
}
}
Example content:
public class ExampleContent : Control
{
public ExampleContent()
{
this.DoubleBuffered = true;
}
static Random random = new Random();
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
var graphics = e.Graphics;
// random color to make the clip rectangle visible in an unobtrusive way
var color = Color.FromArgb(random.Next(160, 180), random.Next(160, 180), random.Next(160, 180));
graphics.Clear(color);
Debug.WriteLine(this.AutoScrollOffset.X.ToString() + ", " + this.AutoScrollOffset.Y.ToString());
CheckerboardRenderer.DrawCheckerboard(
graphics,
this.AutoScrollOffset,
e.ClipRectangle,
new Size(50, 50)
);
StaticBoxRenderer.DrawBoxes(graphics, new Point(0, this.AutoScrollOffset.Y), 100, 30);
}
}
public static class CheckerboardRenderer
{
public static void DrawCheckerboard(Graphics g, Point origin, Rectangle bounds, Size squareSize)
{
var numSquaresH = (bounds.Width + squareSize.Width - 1) / squareSize.Width + 1;
var numSquaresV = (bounds.Height + squareSize.Height - 1) / squareSize.Height + 1;
var startBoxH = (bounds.X - origin.X) / squareSize.Width;
var startBoxV = (bounds.Y - origin.Y) / squareSize.Height;
for (int i = startBoxH; i < startBoxH + numSquaresH; i++)
{
for (int j = startBoxV; j < startBoxV + numSquaresV; j++)
{
if ((i + j) % 2 == 0)
{
Random random = new Random(i * j);
var color = Color.FromArgb(random.Next(70, 95), random.Next(70, 95), random.Next(70, 95));
var brush = new SolidBrush(color);
g.FillRectangle(brush, i * squareSize.Width + origin.X, j * squareSize.Height + origin.Y, squareSize.Width, squareSize.Height);
brush.Dispose();
}
}
}
}
}
public static class StaticBoxRenderer
{
public static void DrawBoxes(Graphics g, Point origin, int boxWidth, int boxHeight)
{
int height = origin.Y;
int left = origin.X;
for (int i = 0; i < 25; i++)
{
Rectangle r = new Rectangle(left, height, boxWidth, boxHeight);
g.FillRectangle(Brushes.White, r);
g.DrawRectangle(Pens.Black, r);
height += boxHeight;
}
}
}