- paths
- The paths to browse. This can be a directories and files.
- searchPattern
- The search string to match against the names of files in path. The parameter cannot end in two periods ("..") or contain two periods ("..") followed by System.IO.Path.DirectorySeparatorChar or System.IO.Path.AltDirectorySeparatorChar, nor can it contain any of the characters in System.IO.Path.InvalidPathChars.
- flags
- An RasterThumbnailBrowserLoadFlags enumeration that can be a combination of the following:
Value Description RasterThumbnailBrowserLoadFlags.None Default mode, the method will return immediatly and the thumbnails are loaded in a background thread. RasterThumbnailBrowserLoadFlags.Block The method will not return until all thumbnails are loaded. RasterThumbnailBrowserLoadFlags.OnlyValidImageFiles Only valid image files are loaded. Any file that contains data not recognized by the RasterThumbnailBrowser.Codecs object as a valid image file will not be loaded.
Visual Basic (Declaration) | |
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Overloads Public Sub LoadThumbnails( _ ByVal paths As IEnumerable(Of String), _ ByVal searchPattern As String, _ ByVal flags As RasterThumbnailBrowserLoadFlags _ ) |
Visual Basic (Usage) | ![]() |
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Dim instance As RasterThumbnailBrowser Dim paths As IEnumerable(Of String) Dim searchPattern As String Dim flags As RasterThumbnailBrowserLoadFlags instance.LoadThumbnails(paths, searchPattern, flags) |
C# | |
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public void LoadThumbnails( IEnumerable<string> paths, string searchPattern, RasterThumbnailBrowserLoadFlags flags ) |
C++/CLI | |
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public: void LoadThumbnails( IEnumerable<String^>^ paths, String^ searchPattern, RasterThumbnailBrowserLoadFlags flags ) |
Parameters
- paths
- The paths to browse. This can be a directories and files.
- searchPattern
- The search string to match against the names of files in path. The parameter cannot end in two periods ("..") or contain two periods ("..") followed by System.IO.Path.DirectorySeparatorChar or System.IO.Path.AltDirectorySeparatorChar, nor can it contain any of the characters in System.IO.Path.InvalidPathChars.
- flags
- An RasterThumbnailBrowserLoadFlags enumeration that can be a combination of the following:
Value Description RasterThumbnailBrowserLoadFlags.None Default mode, the method will return immediatly and the thumbnails are loaded in a background thread. RasterThumbnailBrowserLoadFlags.Block The method will not return until all thumbnails are loaded. RasterThumbnailBrowserLoadFlags.OnlyValidImageFiles Only valid image files are loaded. Any file that contains data not recognized by the RasterThumbnailBrowser.Codecs object as a valid image file will not be loaded.
This example will load two files and expands the multipage one.
Visual Basic | ![]() |
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Private Class MyForm2 : 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 Dim files As String() = New String(1) {Path.Combine(folderPath, "\image1.jpx"), folderPath} theBrowser.LoadThumbnails(files, "*.jpg", RasterThumbnailBrowserLoadFlags.Block Or RasterThumbnailBrowserLoadFlags.ExpandMultiPageFile) 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} Total Pages: {2} Page:{3}", e.FileName, e.Add, e.TotalPages, e.Page) 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_RasterThumbnailBrowser() 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 |
C# | ![]() |
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class MyForm2 : 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; string[] files = new string[2] { Path.Combine(folderPath , "\\image1.jpx"), folderPath }; theBrowser.LoadThumbnails(files, "*.jpg", RasterThumbnailBrowserLoadFlags.Block | RasterThumbnailBrowserLoadFlags.ExpandMultiPageFile); } 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} Total Pages : {2} Page : {3}", e.FileName, e.Add, e.TotalPages, e.Page); } 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 MyForm2() { 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_LoadThumbnails2() { MyForm form = new MyForm(); form.ShowDialog(); form.Cleanup(); } static class LEAD_VARS { public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images"; } |
Use the RasterThumbnailBrowser.LoadThumbnails method to populate the RasterThumbnailBrowser control with the thumbnails of image files found in the directory specified by path. The control will load the images in the following manner:
- All items already in control are cleared.
- The control will create an item for each file that matches searchPattern.
- If RasterThumbnailBrowserLoadFlags.OnlyValidImageFiles is specified in flags, the control will use the Leadtools.Codecs.RasterCodecs.GetInformation(System.Uri,System.Boolean,System.Int32) method of the RasterThumbnailBrowser.Codecs object to check if the given file contains a valid image or not. If it does not, no item will be created for this file.
- The control fills the FileName property of the item with the name of the file found, Page will be set to 1, Text with file name and extension of the specified file and Image with LoadingThumbnail. If RasterThumbnailBrowserLoadFlags.Block is specified in flags, the control will then continue to load the thumbnails for all items before returning. If RasterThumbnailBrowserLoadFlags.Block is not specified, the control will create a background thread to load the thumbnails for all the items and return control to the caller at this stage.
- The control will raise the LoadThumbnail event for each item before it creates the thumbnail for it. You can use this event to update a progress bar, cancel the operation or load the thumbnail yourself.
- If the non-blocking loading operation is specified, you can check the IsLoadingThumbnails at any time to determine whether the control has more items to load.
- The FinishedLoadingThumbnails event is raised by the control when the thumbnails of all items have been created.
- The CancelLoadingThumbnails method can be called at any time to abort creating the thumbnails of all items.
Target Platforms: Microsoft .NET Framework 2.0, Windows 2000, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7