<ToolboxBitmapAttribute()>
<DefaultPropertyAttribute("ViewStyle")>
<DefaultEventAttribute("SelectedIndexChanged")>
Public Class RasterThumbnailBrowser 
   Inherits RasterImageList
   Implements IComponent, ISynchronizeInvoke, IDisposable, IBindableComponent, IDropTarget, IWin32Window 

Dim instance As RasterThumbnailBrowser

[ToolboxBitmapAttribute()]
[DefaultPropertyAttribute("ViewStyle")]
[DefaultEventAttribute("SelectedIndexChanged")]
public class RasterThumbnailBrowser : RasterImageList, IComponent, ISynchronizeInvoke, IDisposable, IBindableComponent, IDropTarget, IWin32Window  

[ToolboxBitmapAttribute()]
[DefaultPropertyAttribute("ViewStyle")]
[DefaultEventAttribute("SelectedIndexChanged")]
public ref class RasterThumbnailBrowser : public RasterImageList, IComponent, ISynchronizeInvoke, IDisposable, IBindableComponent, IDropTarget, IWin32Window  

Private Class MyForm : Inherits Form
      Public theBrowser As RasterThumbnailBrowser
      Public cancelOperation As Boolean ' Informs us if the user canceled the operation
      Public buttonCancel As Button ' Cancel browse loading
      Public buttonBrowse As Button ' Diplays the browse control
      Public progressBar As ProgressBar ' shows progress of loading browse images
      Private Sub buttonBrowse_Click(ByVal sender As Object, ByVal e As EventArgs)
         ' If we are already loading thumbails, cancel
         ' this operation
         If theBrowser.IsLoadingThumbnails Then
            theBrowser.CancelLoadingThumbnails()
         End If

         ' Clean all the items
         theBrowser.Items.Clear()

         ' Update the application state
         buttonCancel.Enabled = True
         progressBar.Value = 0

         ' And load the new thumbnails
         cancelOperation = False

         Dim folderPath As String = LEAD_VARS.ImagesDir
         theBrowser.LoadThumbnails(folderPath, "*.*", RasterThumbnailBrowserLoadFlags.Block)

         theBrowser.Refresh()

         theBrowser.EnableBroswerWatcher = True
      End Sub

      Private Sub thumbnailBrowser_LoadThumbnail(ByVal sender As Object, ByVal e As RasterThumbnailBrowserLoadThumbnailEventArgs)
         ' If this is the first iteration, update the progress bar minimum and maximum values
         If e.Index = 0 Then
            progressBar.Minimum = 0
            progressBar.Maximum = e.Total - 1
         End If

         ' 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 Then
            e.Cancel = True
         End If
      End Sub

      Private Sub thumbnailBrowser_AddFile(ByVal sender As Object, ByVal e As RasterThumbnailBrowserAddFileEventArgs)
         Console.WriteLine("AddFile: {0}    Add: {1}", e.FileName, e.Add)
      End Sub

      Private Sub thumbnailBrowser_FinishedLoadingThumbnails(ByVal sender As Object, ByVal e As EventArgs)
         buttonCancel.Enabled = False
      End Sub

      Private Sub buttonCancel_Click(ByVal sender As Object, ByVal e As EventArgs)
         ' The user has clicked the cancel button
         Me.cancelOperation = True
      End Sub

      ' Create  custom images to use as the "error" and "loading" thumbnails.
      Private Sub CreateErrorThumbnail()
         ' Get the image size
         Dim imageSize As Size = theBrowser.ItemImageSize

         ' No "loading" thumbnail
         theBrowser.LoadingThumbnail = Nothing

         ' For the "error" thumbnail, create a red X image
         Dim palette As RasterColor() = New RasterColor() {}
         Dim image As RasterImage = New RasterImage(RasterMemoryFlags.Conventional, imageSize.Width, imageSize.Height, 24, RasterByteOrder.Bgr, RasterViewPerspective.TopLeft, palette, IntPtr.Zero, 0)

         Dim hdc As IntPtr = RasterImagePainter.CreateLeadDC(image)
         Dim g As Graphics = 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
      End Sub

      Public Sub Cleanup()
         RemoveHandler buttonBrowse.Click, AddressOf buttonBrowse_Click
         RemoveHandler buttonCancel.Click, AddressOf buttonCancel_Click
         RemoveHandler theBrowser.LoadThumbnail, AddressOf thumbnailBrowser_LoadThumbnail
         RemoveHandler theBrowser.FinishedLoadingThumbnails, AddressOf thumbnailBrowser_FinishedLoadingThumbnails
      End Sub

      Public Sub New()
         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
         AddHandler theBrowser.LoadThumbnail, AddressOf thumbnailBrowser_LoadThumbnail
         AddHandler theBrowser.FinishedLoadingThumbnails, AddressOf thumbnailBrowser_FinishedLoadingThumbnails
         AddHandler theBrowser.AddFile, AddressOf thumbnailBrowser_AddFile

         ' Create a thumbnail image to be displayed on error
         CreateErrorThumbnail()

         ' add a panel
         Dim panel As 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)
         AddHandler buttonBrowse.Click, AddressOf buttonBrowse_Click

         ' add a "cancel" button
         buttonCancel = New Button()
         buttonCancel.Text = "Cancel"
         buttonBrowse.Dock = DockStyle.Bottom
         panel.Controls.Add(buttonCancel)
         AddHandler buttonCancel.Click, AddressOf buttonCancel_Click

         ' add a progress bar
         progressBar = New ProgressBar()
         progressBar.Dock = DockStyle.Bottom
         Controls.Add(progressBar)

         Controls.Add(theBrowser)
         theBrowser.BringToFront()
      End Sub

      Private Sub InitializeComponent()
         Me.SuspendLayout()
         ' 
         ' MyForm
         ' 
         Me.ClientSize = New System.Drawing.Size(315, 273)
         Me.Name = "MyForm"
         Me.ResumeLayout(False)

      End Sub
   End Class
   Public Sub RasterThumbnailBrowser_LoadThumbnails2()
      Dim form As MyForm = New MyForm()
      form.ShowDialog()
      form.Cleanup()
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class

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.LoadThumbnails(folderPath, "*.*", RasterThumbnailBrowserLoadFlags.Block);

         theBrowser.Refresh();

         theBrowser.EnableBroswerWatcher = 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:\Users\Public\Documents\LEADTOOLS Images";
}