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Dynamically display an array of PictureBoxes - Performance issue

I'd like to display coverarts for each album of an MP3 library, a bit like Itunes does (at a later stage, i'd like to click one any of these coverarts to display the list of songs).
I have a form with a panel panel1 and here is the loop i'm using :
int i = 0;
int perCol = 4;
int disBetWeen = 15;
int width = 250;
int height = 250;
foreach(var alb in mp2)
{
myPicBox.Add(new PictureBox());
myPicBox[i].SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;
myPicBox[i].Location = new System.Drawing.Point(disBetWeen + (disBetWeen * (i % perCol) +(width * (i % perCol))),
disBetWeen + (disBetWeen * (i / perCol))+ (height * (i / perCol)));
myPicBox[i].Name = "pictureBox" + i;
myPicBox[i].Size = new System.Drawing.Size(width, height);
myPicBox[i].ImageLocation = #"C:/Users/Utilisateur/Music/label.jpg";
panel1.Controls.Add(myPicBox[i]);
i++;
}
I'm using the same picture per picturebox for convenience, but i'll use the coverart embedded in each mp3 file eventually.
It's working fine with an abstract of the library (around 50), but i have several thousands of albums. I tried and as expected, it takes a long time to load and i cannot really scroll afterward.
Is there any way to load only what's displayed ? and then how to assess what is displayed with the scrollbars.
Thanks

Winforms really isn't suited to this sort of thing... Using standard controls, you'd probably need to either provision all the image boxes up front and load images in as they become visible, or manage some overflow placeholder for the appropriate length so the scrollbars work.
Assuming Winforms is your only option, I'd suggest you look into creating a custom control with a scroll bar and manually driving the OnPaint event.
That would allow you to keep a cache of images in memory to draw the current view [and a few either side], while giving you total control over when they're loaded/unloaded [well, as "total" as you can get in a managed language - you may still need tune garbage collection]
To get into some details....
Create a new control
namespace SO61574511 {
// Let's inherit from Panel so we can take advantage of scrolling for free
public class ImageScroller : Panel {
// Some numbers to allow us to calculate layout
private const int BitmapWidth = 100;
private const int BitmapSpacing = 10;
// imageCache will keep the images in memory. Ideally we should unload images we're not using, but that's a problem for the reader
private Bitmap[] imageCache;
public ImageScroller() {
//How many images to put in the cache? If you don't know up-front, use a list instead of an array
imageCache = new Bitmap[100];
//Take advantage of Winforms scrolling
this.AutoScroll = true;
this.AutoScrollMinSize = new Size((BitmapWidth + BitmapSpacing) * imageCache.Length, this.Height);
}
protected override void OnPaint(PaintEventArgs e) {
// Let Winforms paint its bits (like the scroll bar)
base.OnPaint(e);
// Translate whatever _we_ paint by the position of the scrollbar
e.Graphics.TranslateTransform(this.AutoScrollPosition.X,
this.AutoScrollPosition.Y);
// Use this to decide which images are out of sight and can be unloaded
var current_scroll_position = this.HorizontalScroll.Value;
// Loop through the images you want to show (probably not all of them, just those close to the view area)
for (int i = 0; i < imageCache.Length; i++) {
e.Graphics.DrawImage(GetImage(i), new PointF(i * (BitmapSpacing + BitmapWidth), 0));
}
}
//You won't need a random, just for my demo colours below
private Random rnd = new Random();
private Bitmap GetImage(int id) {
// This method is responsible for getting an image.
// If it's already in the cache, use it, otherwise load it
if (imageCache[id] == null) {
//Do something here to load an image into the cache
imageCache[id] = new Bitmap(100, 100);
// For demo purposes, I'll flood fill a random colour
using (var gfx = Graphics.FromImage(imageCache[id])) {
gfx.Clear(Color.FromArgb(255, rnd.Next(0, 255), rnd.Next(0, 255), rnd.Next(0, 255)));
}
}
return imageCache[id];
}
}
}
And Load it into your form, docking to fill the screen....
public Form1() {
InitializeComponent();
this.Controls.Add(new ImageScroller {
Dock = DockStyle.Fill
});
}
You can see it in action here: https://www.youtube.com/watch?v=ftr3v6pLnqA (excuse the mouse trails, I captured area outside the window)

Dynamically add Chart to Windows Forms - shows up blank

I'm trying to add a Chart control dynamically to a Form (using C#, this should all be .NET 4.0), but it's always blank (only the background color shows). I tried the same code in a Form that already has a control and it works, so I imagine it's some initialization function I should call (I tried Invalidate() on the control and Refresh() on both control and the panel it's being placed in, made no difference). I went through the few similar posts I found, tried throwing in any other commands they used (BeginInit() is from one such post) but no luck so far. Any ideas?
BTW I want to display 6-9 charts (position, speed and acceleration in 3D space) so I'd rather add them dynamically than have 9 sets of assignments. Here's the code that adds the charts to the panel:
foreach (KeyValuePair<string, List<double>> p in b.storedValues)
{
Control c = getChartForData(p);
panel1.Controls.Add(c);
c.Invalidate();
c.Refresh();
break;
}
And the function that creates each chart:
private Chart getChartForData(KeyValuePair<string, List<double>> data)
{
Chart c = new Chart();
((System.ComponentModel.ISupportInitialize)c).BeginInit();
c.Series.Clear();
c.BackColor = Color.White;
c.Height = 300;
c.Width = 500;
c.Palette = ChartColorPalette.Bright;
Series s = new Series(data.Key);
s.ChartType = SeriesChartType.Spline;
double maxValue = 0;
//NOTE: Going logarithmic on this, too big numbers
for (int i = 0; i < data.Value.Count; i++)
{
maxValue = Math.Max(Math.Log10(data.Value[i]), maxValue);
}
for (int i = 0; i < data.Value.Count; i++)
{
s.Points.AddXY(i,Math.Log10(data.Value[i]) * c.Height / maxValue);
}
c.Series.Add(s);
return c;
}
Many thanks in advance.

When you create a Chart yourself, in code, it does not contain any ChartArea.
Therefore, nothing is displayed.
I'm guessing that the designer generates some code to initialize a default chart area when you drag and drop a chart control onto the form.
Also, you should really let the chart control handle the layout, instead of calculating the desired position of each point based on the height of the chart control.
I would go as simple as possible to get something that's working, and then you can tweak the range of the axis afterwards. You can also set an axis to be logarithmic.
Start with trying out this minimal version, and make sure that displays something, before you complicate things. This works for me.
private Chart getChartForData(string key, List<double> data)
{
Chart c = new Chart();
Series s = new Series(key);
s.ChartType = SeriesChartType.Spline;
for (int i = 0; i < data.Count; i++)
{
s.Points.AddXY(i, data[i]);
}
c.Series.Add(s);
var area = c.ChartAreas.Add(c.ChartAreas.NextUniqueName());
s.ChartArea = area.Name;
// Here you can tweak the axis of the chart area - min and max value,
// where they display "ticks", and so on.
return c;
}

User Control vs. Rectangle/Alternatives

I'm creating a program that is a tile based dungeon editor to develop games. The tiles that are shown on screen are user controls that are dynamically created once the user specifies the height and width of the level. These user controls are then added to a panel.
My main concern is the efficiency of what I'm doing. If a user creates a 20x20 level, will the amount of user controls "bog down" the program? Each control (or tile as it were) will hold an image and some other attributes such as collidable, interactive, etc.
Will I be okay using user controls, or is there a less expensive alternative out there for this sort of thing?
EDIT: Thanks for the initial replies! From what you guys have said, this won't be too expensive. However, what about the performance in terms of resizing these controls?
private void changeTileSizeOnScroll(object sender, EventArgs e)
{
int newSize = sliderTileResizer.Value;
for (int w = 0; w < matrixWidth; w++)
{
for (int h = 0; h < matrixHeight; h++)
{
pnlTileEditor.Controls[w * matrixHeight + h].Size = new Size(newSize, newSize);
pnlTileEditor.Controls[w * matrixHeight + h].Location = new Point(newSize * w - w, newSize * h - h);
}
}
}
I was going to use databinding for the trackbar and tiles, but I need to update the location based on the size of the tiles so that each tile is directly beside the previous one. Is this a terrible way to resize?

How to populate a window with a dictionary of images?

I have a GUI with a button that will open a new window. As soon as the window opens I need it to be filled with a sires of pictures that I have stored in a dictionary of (string,bitmap) with the string representing the path name. Obviously I need to iterate across the dictionary but I don't know what code to use to display the pictures. Is there anyway to make a loop that will automatically display the images in a set size.
For a good example of the output I'm looking for, think windows explorer thumbnails when browsing a folder of pictures.
I know very little about working with images or GUIs so any assistance would be appreciated.
As of now my this is the code I have:
MyPalletGui.Show();
PictureBox myPicBox = new PictureBox();
Dictionary<string,Bitmap> MyPallet = MyImageCollection.ToDictionary();
int xcor = 0;
int ycor = 0;
foreach (Bitmap curtImage in MyPallet.Values){
xcor += 50;
ycor += 50;
myPicBox.Location = new Point(xcor, ycor);
myPicBox.Width = 50;
myPicBox.Height = 50;
myPicBox.Visible = true;
myPicBox.Image = new Bitmap(curtImage);
this.MyPalletGui.Controls.Add(myPicBox);
I need to work with the x and y coordinates more, but the code above displays nothing.

Displaying moving pieces in my chess game lags, what can I do about it?

First time I ever ask a question here so correct me if I´m doing it wrong.
Picture of my chess set:
Every time I move a piece it lags for about 1 second. Every piece and tile has an Image and there is exactly 96 Images. Every time I move a piece it clears everything with black and then update the graphics.
In the early stages of the chess I didn't have any Images and used different colors instead and only a few pieces there was no noticeable lag and the piece moved in an instant.
public void updateGraphics(PaintEventArgs e, Graphics g, Bitmap frame)
{
g = Graphics.FromImage(frame);
g.Clear(Color.Black);
colorMap(g);
g.Dispose();
e.Graphics.DrawImageUnscaled(frame, 0, 0);
}
The function colorMap(g) looks like this:
private void colorMap(Graphics g)
{
for (int y = 0; y < SomeInts.amount; y++)
{
for (int x = 0; x < SomeInts.amount; x++)
{
//Tiles
Bundle.tile[x, y].colorBody(g, x, y);
//Pieces
player1.colorAll(g);
player2.colorAll(g);
}
}
}
The colorAll function executes every pieces colorBody(g) function which look like this:
public void colorBody(Graphics g)
{
//base.colorBody() does the following: body = new Rectangle(x * SomeInts.size + SomeInts.size / 4, y * SomeInts.size + SomeInts.size / 4, size, size);
base.colorBody();
if (team == 1)
{
//If its a white queen
image = Image.FromFile("textures/piece/white/queen.png");
}
if (team == 2)
{
//If its a black queen
image = Image.FromFile("textures/piece/black/queen.png");
}
g.DrawImage(image, body);
}
and finaly the function that moves the piece:
public void movePiece(MouseEventArgs e)
{
for (int y = 0; y < SomeInts.amount; y++)
{
for (int x = 0; x < SomeInts.amount; x++)
{
if (Bundle.tile[x, y].body.Contains(e.Location))
{
//Ignore this
for (int i = 0; i < queens.Count; i++)
{
Queen temp = queens.ElementAt<Queen>(i);
temp.move(x, y);
}
//Relevant
player1.move(x, y);
player2.move(x, y);
}
}
}
}
Thank you for reading all this! I could make a link to the whole program if my coding examples is not enough.

You're calling Image.FromFile in every refresh, for every image - effectively reloading every image file every time from disk.
Have you considered loading the images once, and storing the resulting Images somewhere useful? (say, an array, Image[2,6] would be adequate)

Why do you redraw the board each time? Can't you just leave the board where it is and display an image with transparent background over it? That way you have one image as a background (the board), plus 64 smaller images placed over the board in a grid and just change the image being displayed on each move.
That way, you can let windows handle the drawing...
Also, load the images of the pieces at the start of the application.

In addition to not calling Image.FromFile() inside updateGraphics() (which is definitely your biggest issue), you shouldn't be attempting to redraw the entire board every on every call to updateGraphics() - most of the time, only a small portion of the board will be invalidated.
The PaintEventArgs contains an parameter, ClipRectangle, which specifies which portion of the board needs redrawing. See if you can't figure out which tiles intersect with that rectangle, and only redraw those tiles :)
Hint: Write a function Point ScreenToTileCoords(Point) which takes a screen coordinate and returns which board-tile is at that coordinate. Then the only tiles you need to redraw are
Point upperLeftTileToBeDrawn = ScreenToTileCoords(e.ClipRectangle.Left, e.ClipRectangle.Top);
Point lowerRightTileToBeDrawn = ScreenToTileCoords(e.ClipRectangle.Right - 1, e.ClipRectangle.Bottom- 1);
Also, make sure your control is double-buffered, to avoid tearing. This is much simpler than #Steve B's link in the comments above states; assuming this is a UserControl, simply set
this.DoubleBuffered = true;

Well, what about this:
Do not clear the whole board but only those parts that need to be cleared.
Alternative:
Update to WPF - it moves drawing to the graphics card - and just move pieces around, in a smart way (i.e. have a control / object for every piece).