How can i make pictureboxe on the form more fastly on runtime in .net winforms?

Question

I want to select the pictures (They are select during program is running) and show them on the form. for that i take a panel on the form and populate the panel with pictureboxes.i write the following code for that but it is very time consuming:

if(openDialoge1.ShowDialog() == DialogResult.OK)
                {
                   string[] fileName = open.FileNames;
                   foreach (string s in fileName)
                   {
                        pBox = new PictureBox();
                        pBox.Size = new System.Drawing.Size(w, h);
                        pBox.Location = new System.Drawing.Point(x, y);
                        pBox.Image = Image.FromFile(s);
                        pBox.SizeMode = PictureBoxSizeMode.StretchImage;
                        .
                        .//here i add some eventHandler of picture boxes.

                        this.panel1.Controls.Add(pBox);
                        x += pBox.Width + 4;
                     }
                 } //here w,h,x,y are integers.

This code work well, but it is very time consuming and take much time to populate the panel with picture boxes. for example when i slect the 20,30 pictures, it take much time. Is there any way that reduce the time to populate the panel with pictureboxes.

Thanks in advance.

Answer 1

You might consider profiling your method. If you don't have a profiler like ANTS available, you can roll your own:

Stopwatch watch = new Stopwatch();
watch.Start();

//code to profile goes here

watch.Stop();
Console.Writeln("Elapsed time: " + watch.Elapsed.TotalMilliseconds + "ms");

This will help you pinpoint which part of your code is slow.

I can tell you right now that Image.FromFile() is probably the slowest part. What you might consider is loading the images into a List<> first, using a separate thread or background worker. This will let you show a progress bar or hourglass, to let the user know that images are being read from disk.

Once the images are in memory, creating the picture boxes will go a lot faster.

Edit:

You've requested an example showing how to load images into memory first. It's really simple:

// this code should run in its own thread - BackgroundWorker is perfect for this

List<Image> images = new List<Image>();
foreach (string imagePath in paths)
{
   images.Add(Image.FromFile(imagePath));

   // update progress bar here?
}

Now, you have a list of your images which you can use to fill your picture boxes.