Gets or sets the Leadtools.Codecs.RasterCodecs object used to load the thumbnail images.
public RasterCodecs Codecs { get; set; }
A Leadtools.Codecs.RasterCodecs object used to load the thumbnail images. Default value is a null reference (Nothing in VB).
The RasterThumbnailBrowser control automatically loads and creates thumbnails for the images found on the disk folder when the LoadThumbnails(String,String,RasterThumbnailBrowserLoadFlags) method is called. You need to set the Codecs property with an instance of the Leadtools.Codecs.RasterCodecs class to be used to load these images. You can re-use the Leadtools.Codecs.RasterCodecs object that you are using in your main application.
using Leadtools.WinForms;
using Leadtools;
using Leadtools.Codecs;
using Leadtools.Drawing;
class MyForm : Form
{
public RasterThumbnailBrowser theBrowser;
public bool cancelOperation; // Informs us if the user canceled the operation
public Button buttonCancel; // Cancel browse loading
public Button buttonBrowse; // Diplays the browse control
public ProgressBar progressBar; // shows progress of loading browse images
void buttonBrowse_Click(object sender, EventArgs e)
{
// If we are already loading thumbails, cancel
// this operation
if (theBrowser.IsLoadingThumbnails)
theBrowser.CancelLoadingThumbnails();
// Clean all the items
theBrowser.Items.Clear();
// Update the application state
buttonCancel.Enabled = true;
progressBar.Value = 0;
// And load the new thumbnails
cancelOperation = false;
string folderPath = LEAD_VARS.ImagesDir;
theBrowser.LoadStamp = true;
theBrowser.LoadThumbnails(folderPath, "*.*", RasterThumbnailBrowserLoadFlags.Block);
theBrowser.Refresh();
theBrowser.EnableBrowserWatcher = true;
}
private void thumbnailBrowser_LoadThumbnail(object sender, RasterThumbnailBrowserLoadThumbnailEventArgs e)
{
// If this is the first iteration, update the progress bar minimum and maximum values
if (e.Index == 0)
{
progressBar.Minimum = 0;
progressBar.Maximum = e.Total - 1;
}
// Update where we are in the loading operation
progressBar.Value = e.Index;
// Check if we need to cancel (due to the user clicking the Cancel button)
if (cancelOperation)
e.Cancel = true;
}
private void thumbnailBrowser_AddFile(object sender, RasterThumbnailBrowserAddFileEventArgs e)
{
Console.WriteLine("AddFile: {0} Add: {1}", e.FileName, e.Add);
}
private void thumbnailBrowser_FinishedLoadingThumbnails(object sender, EventArgs e)
{
buttonCancel.Enabled = false;
}
private void buttonCancel_Click(object sender, EventArgs e)
{
// The user has clicked the cancel button
this.cancelOperation = true;
}
// Create custom images to use as the "error" and "loading" thumbnails.
void CreateErrorThumbnail()
{
// Get the image size
Size imageSize = theBrowser.ItemImageSize;
// No "loading" thumbnail
theBrowser.LoadingThumbnail = null;
// For the "error" thumbnail, create a red X image
RasterColor[] palette = new RasterColor[0];
RasterImage image = new RasterImage(
RasterMemoryFlags.Conventional,
imageSize.Width,
imageSize.Height,
24,
RasterByteOrder.Bgr,
RasterViewPerspective.TopLeft,
palette,
IntPtr.Zero,
0
);
IntPtr hdc = RasterImagePainter.CreateLeadDC(image);
Graphics g = Graphics.FromHdc(hdc);
g.FillRectangle(Brushes.Magenta, 0, 0, imageSize.Width, imageSize.Height);
g.DrawLine(Pens.Red, 0, 0, imageSize.Width, imageSize.Height);
g.DrawLine(Pens.Red, imageSize.Width, 0, 0, imageSize.Height);
g.Dispose();
RasterImagePainter.DeleteLeadDC(hdc);
// Make this image transparent
image.Transparent = true;
image.TransparentColor = RasterColor.FromKnownColor(RasterKnownColor.Magenta);
theBrowser.ErrorThumbnail = image;
}
public void Cleanup()
{
buttonBrowse.Click -= new EventHandler(buttonBrowse_Click);
buttonCancel.Click -= new EventHandler(buttonCancel_Click);
theBrowser.LoadThumbnail -= new EventHandler<RasterThumbnailBrowserLoadThumbnailEventArgs>(thumbnailBrowser_LoadThumbnail);
theBrowser.FinishedLoadingThumbnails -= new EventHandler(thumbnailBrowser_FinishedLoadingThumbnails);
}
public MyForm()
{
Size = new Size(300, 200);
// create the browser
theBrowser = new RasterThumbnailBrowser();
theBrowser.Codecs = new RasterCodecs();
theBrowser.Dock = DockStyle.Fill;
theBrowser.ItemSpacingSize = new Size(10, 10);
theBrowser.ThumbnailSizeFlags = RasterSizeFlags.Bicubic;
theBrowser.LoadThumbnail += new EventHandler<RasterThumbnailBrowserLoadThumbnailEventArgs>(thumbnailBrowser_LoadThumbnail);
theBrowser.FinishedLoadingThumbnails += new EventHandler(thumbnailBrowser_FinishedLoadingThumbnails);
theBrowser.AddFile += new EventHandler<RasterThumbnailBrowserAddFileEventArgs>(thumbnailBrowser_AddFile);
// Create a thumbnail image to be displayed on error
CreateErrorThumbnail();
// add a panel
Panel panel = new Panel();
panel.Dock = DockStyle.Left;
panel.Width = 100;
Controls.Add(panel);
panel.BringToFront();
// add a "browse" button
buttonBrowse = new Button();
buttonBrowse.Text = "Browse";
buttonBrowse.Dock = DockStyle.Top;
panel.Controls.Add(buttonBrowse);
buttonBrowse.Click += new EventHandler(buttonBrowse_Click);
// add a "cancel" button
buttonCancel = new Button();
buttonCancel.Text = "Cancel";
buttonBrowse.Dock = DockStyle.Bottom;
panel.Controls.Add(buttonCancel);
buttonCancel.Click += new EventHandler(buttonCancel_Click);
// add a progress bar
progressBar = new ProgressBar();
progressBar.Dock = DockStyle.Bottom;
Controls.Add(progressBar);
Controls.Add(theBrowser);
theBrowser.BringToFront();
}
private void InitializeComponent()
{
this.SuspendLayout();
//
// MyForm
//
this.ClientSize = new System.Drawing.Size(315, 273);
this.Name = "MyForm";
this.ResumeLayout(false);
}
}
public void RasterThumbnailBrowser_RasterThumbnailBrowser()
{
MyForm form = new MyForm();
form.ShowDialog();
form.Cleanup();
}
static class LEAD_VARS
{
public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images";
}