Help me to optimize code in C#

Question

0.00/5 (No votes)

See more:

Hi everyone!

I have a list to save .jpg files path

private List<string> images = new List<string>();

I want to fill it with pictures. For example, user selected a folder
with FolderBrowserDialog

  if (this.folderBrowserDialog1.ShowDialog() == DialogResult.OK)
  {
          // --- clear previous results ---
         this.images.Clear();
      
      { // I intentionally put brackets here to create a scope ---
         FileInfo[] files = 
(new DirectoryInfo(folderBrowserDialog1.SelectedPath)).GetFiles("*.jpg");
         
         foreach(FileInfo pic in files)
             this.images.Add(pic.FullName);

       } 
     
   using(FileStream fs = new FileStream(images[0], FileMode.Open))
   {
       this.pictureBox.Image = Image.FromStream(fs);
    }

  }

I have two questions
First, if I created that "scope" and i put FileInfo references there
so after the closing bracket they would be out of scope and thus
they will be popped out of stack....Right? Will it save memory that
my application uses? Or will it simply destroy references and will
not free up heap memory where FileInfo references point???

Second, is it effective to open images in Stream like I did??
I used to create a Bitmap object and then I loaded it onto PictureBox
and it was slower (even without deep examing)...

Is there any another way to optimize image loading like "stream cache" or something??
Please help

Posted 30-Apr-10 4:58am

Nick Reshetinsky

Updated 30-Apr-10 7:24am

#realJSOP

v2

Add a Solution

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Luc Pattyn · Answer 1 · 2010-04-30T10:22:00

Hi Nick,

1.
you don't need the FileInfo[] array at all, as all you use is the names anyway. Have a look at Directory.GetFiles(); that one returns an array of strings, much cheaper, much faster.

2.
assuming images is a List<string> or something similar, you don't need the foreach loop, just try images.AddRange()

3.
I don't think the way to load the image into memory and into the PictureBox will matter much. The simplest probably is pictureBox.ImageLocation=images[0];

4.
What will affect performance is you disposing of images you no longer need, so if you plan on cycling them towards your PictureBox, you may want to do it like this:

foreach(string s in images) {
    Bitmap bm=new Bitmap(s);
    pictureBox.Image=bm;
    // insert something that takes a while so you can see the image...
    pictureBox.Image=null;
    bm.Dispose();
}

:)

OriginalGriff · Answer 2 · 2010-04-30T05:42:00

Nick Reshetinsky wrote:
f I created that "scope" and i put FileInfo references there
so after the closing bracket they would be out of scope and thus
they will be popped out of stack....Right? Will it save memory that
my application uses? Or will it simply destroy references and will
not free up heap memory where FileInfo references point?

Yes and no. When the "files" array goes out of scope at the end of the block, all the elements of the array (all the FileInfo variables) are available for garbage collection, because nothing else refers to them. They won't however be deleted until the GC actually gets round to it - which may be immediately, or may be next year. It really doesn't matter!

Without actually measuring it (and I don't have time at the moment) I would be suprised if

this.pictureBox.Image = Image.FromStream(fs);

was significantly slower than

this.pictureBox.Image = new Bitmap(pathNameString);

as I would expect the Bitmap constructor to use a stream anyway...
Did you try

this.pictureBox.Image = Image.FromFile(pathNameString);

and if so did that make any difference?

Help me to optimize code in C#

2 solutions

Solution 2

Solution 1

Add your solution here

Preview 0