performance woes
David Smith
dlgOpen.ShowDialog()
ListView1.BeginUpdate()
ListView1.AutoArrange = False
ImageList1.Images.Clear()
ListView1.Items.Clear()
Dim fileSys As System.IO.Directory
Dim intCountPaths As Integer = 0
For Each path As String In fileSys.GetFiles(dlgOpen.SelectedPath)
Dim fileProps As New System.IO.FileInfo(path)
If LCase(fileProps.Name).EndsWith(".jpg") Then
ImageList1.Images.Add(System.Drawing.Image.FromFile(dlgOpen.SelectedPath & "\" & fileProps.Name))
ListView1.Items.Add(fileProps.Name, intCountPaths)
ListView1.Items(intCountPaths).Tag = dlgOpen.SelectedPath & "\" & fileProps.Name
intCountPaths += 1
End If
Next path
ListView1.EndUpdate()
Any ideas on how to speed things up?
Thanks!
--dave
_________________
David Smith
(517) 944-1872
smit...@msu.edu
614 Theo
Lansing MI 48917
David J. Smith
I copied the code into a new project and everything is quick as a fox to me. Try it out! =)
If you want more freedom with what you do, (e.g. the max imagesize on an imagelist is 256 pixels.), you may want to try out creating your own custom thumbnail view from a PictureBox, and a label. =)
If this code doesn’t work, you may want to look at your image size.
I’m curious – How big are the images you’re dealing with? (These are itty bitty jpegs after all)
On the Form, we have:
A ListView named listView1.
An ImageList named imageList1.
A button named button1.
A FolderBrowserDialog named folderBrowserDialog1.
private void button1_Click(object sender, EventArgs e)
{
if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
{
DirectoryInfo targetDirectory = new DirectoryInfo(folderBrowserDialog1.SelectedPath);
listView1.BeginUpdate(); // don’t update the listview state as we change things
listView1.AutoArrange = false;
listView1.Items.Clear(); // reset the listview, let’s start loading images from scratch
imageList1.Images.Clear(); // reset the imagelist, let’s start loading images from scratch
imageList1.ColorDepth = ColorDepth.Depth32Bit; // 4 – 32 color depth
imageList1.ImageSize = new Size(100, 100); // this can vary from 1 – 256 inclusive
int countPaths = 0; // index into the number of images we’ve added so far
// Go through all the files in a directory
foreach (FileInfo file in targetDirectory.GetFiles()) // Not a performance hit since the JIT does performance optimizations.
{
if (file.Extension == ".jpg") // Apparently, jpegs are important to us. ((file.Extension == ".jpg") || (file.Extension == ".gif")) to add gif support
{
imageList1.Images.Add(Image.FromFile(folderBrowserDialog1.SelectedPath + @"\" + file.Name));
listView1.Items.Add(file.Name, countPaths);
listView1.Items[countPaths].Tag = folderBrowserDialog1.SelectedPath + @"\" + file.Name;
countPaths++;
}
}
listView1.View = View.LargeIcon; // Display images for each item in the listview
listView1.LargeImageList = imageList1; // Bind the ImageList to the listView. (*Important*)
listView1.EndUpdate(); // Start rendering the listview again.
}
}
Cheers!
David J. Smith
Visual C# MVP