Image Property (RasterImageListItem)

The image associated with this RasterImageListItem object.

Syntax

public RasterImage Image {get; set;}

public RasterImage Image {get; set;}

 get_Image();
 set_Image(value);

public:
property RasterImage^ Image {
   RasterImage^ get();
   void set (    RasterImage^ value);
}

'Declaration
 
Public Property Image As RasterImage

'Usage
 
Dim instance As RasterImageListItem
Dim value As RasterImage
 
instance.Image = value
 
value = instance.Image

Property Value

An Leadtools.RasterImage object associated with this RasterImageListItem object. The default value is null (Nothing in Visual Basic).

Remarks

The Page property specifies the 1-based page number to view from this image.

The value of RasterImage.Page is not used to control the page number of the item to be viewed in this item. Instead, use the Page property. This allows the same Leadtools.RasterImage object to be used multiple items while setting the Page property to different values.

The RasterImageList control will paint this image onto the item surface. If the item does not have an image, the value of this property is null (Nothing in Visual Basic) and, nothing is painted.

The RasterImageList control paints the image in the following manner:

If the image size is less than or equal to the ItemImageSize value, the image is painted with its original size only centered onto the item surface.
If the image size is grater than the ItemImageSize value, the image is stretched to this smaller size and the aspect ratio is kept the same.
It is recommended that you populate the items with "thumbnail" images. This will increase the performance of the item painting operation. In such cases, use the Tag or FileName properties to store the information needed to load the image in its original size when requested.

The value of RasterImage.Page is not used to control the page number of the item to be viewed in this item. Instead, use the Page property. This allows the same Leadtools.RasterImage object to be used in multiple items while setting the Page property to different values.

Example

Visual Basic
C#

Private Class MyForm2 : Inherits Form
      Private viewer As RasterImageViewer
      Private imageList As RasterImageList
      Private codecs As RasterCodecs
      Public Sub New()
         ' Set the size of the form
         Size = New Size(400, 200)

         ' Create a new RasterImageList control
         imageList = New RasterImageList()
         imageList.Dock = DockStyle.Left
         imageList.SelectionMode = RasterImageListSelectionMode.Single
         Controls.Add(imageList)
         imageList.BringToFront()

         ' Add a handler to the SelectedIndexChanged event
         AddHandler imageList.SelectedIndexChanged, AddressOf rasterImageList_SelectedIndexChanged

         Dim splitter As Splitter = New Splitter()
         splitter.Dock = DockStyle.Left
         Controls.Add(splitter)
         splitter.BringToFront()

         viewer = New RasterImageViewer()
         viewer.Dock = DockStyle.Fill
         Controls.Add(viewer)
         viewer.BringToFront()

         ' Now load all our images
         codecs = New RasterCodecs()

         Dim folderName As String = LEAD_VARS.ImagesDir
         Dim files As String() = Directory.GetFiles(folderName, "*.*")

         ' This is going to be a lengthy operation
         ' Suspend painting the RasterImageList
         imageList.BeginUpdate()

         For Each fileName As String In files
            ' Load the image as a thumbnail
            Dim image As RasterImage = LoadThumbnail(fileName)

            ' Only add an item if we loaded the image successfuly
            If Not image Is Nothing Then
               ' Create an item
               Dim item As RasterImageListItem = New RasterImageListItem()


               ' Setup the item information
               item.Image = image
               item.Text = Path.GetFileName(fileName)
               item.Page = 1

               ' To load this image in original size later
               item.FileName = fileName

               ' Add the item into RasterImageList
               imageList.Items.Add(item)
            End If
         Next fileName

         imageList.EndUpdate()

      End Sub

      Private Sub rasterImageList_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
         ' User has selected an item from the RasterImageList control.
         ' Re-load the item image and show it in original size in the viewer

         ' Get the selected item(s)
         Dim selectedItems As RasterImageListItemCollection = imageList.SelectedItems
         If Not selectedItems Is Nothing AndAlso selectedItems.Count = 1 Then
            Dim item As RasterImageListItem = selectedItems(0)

            ' Load the image in its original size and set it in the viewer
            viewer.Image = codecs.Load(item.FileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1)
         End If
      End Sub

      Private Function LoadThumbnail(ByVal fileName As String) As RasterImage
         Dim image As RasterImage = Nothing

         Try
            ' See if we can load this image
            Dim info As CodecsImageInfo = codecs.GetInformation(fileName, False, 1)

            If info.Format <> RasterImageFormat.Unknown Then
               ' Yes, calculate the thumbnail size to fit into RasterImageList.ItemImageSize
               Dim rc As Rectangle = New Rectangle(0, 0, imageList.ItemImageSize.Width, imageList.ItemImageSize.Height)

               rc = RasterImageList.GetFixedAspectRatioImageRectangle(info.Width, info.Height, rc)

               ' Load the thumbnail
               image = codecs.Load(fileName, rc.Width, rc.Height, 24, RasterSizeFlags.Resample, CodecsLoadByteOrder.BgrOrGray, 1, 1)
            Else
               image = Nothing
            End If
         Catch
            image = Nothing
         End Try
         Return image
      End Function
   End Class

   Public Sub RasterImageList_Image()
      Dim form As MyForm2 = New MyForm2()
      form.ShowDialog()
   End Sub

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

class MyForm2 : Form
   {
      RasterImageViewer viewer;
      RasterImageList imageList;
      RasterCodecs codecs;
      public MyForm2()
      {
         // Set the size of the form
         Size = new Size(400, 200);

         // Create a new RasterImageList control
         imageList = new RasterImageList();
         imageList.Dock = DockStyle.Left;
         imageList.SelectionMode = RasterImageListSelectionMode.Single;
         Controls.Add(imageList);
         imageList.BringToFront();

         // Add a handler to the SelectedIndexChanged event
         imageList.SelectedIndexChanged += new EventHandler(rasterImageList_SelectedIndexChanged);

         Splitter splitter = new Splitter();
         splitter.Dock = DockStyle.Left;
         Controls.Add(splitter);
         splitter.BringToFront();

         viewer = new RasterImageViewer();
         viewer.Dock = DockStyle.Fill;
         Controls.Add(viewer);
         viewer.BringToFront();

         // Now load all our images
         codecs = new RasterCodecs();

         string folderName = LEAD_VARS.ImagesDir;
         string[] files = Directory.GetFiles(folderName, "*.*");

         // This is going to be a lengthy operation
         // Suspend painting the RasterImageList
         imageList.BeginUpdate();

         foreach(string fileName in files)
         {
            // Load the image as a thumbnail
            RasterImage image = LoadThumbnail(fileName);

            // Only add an item if we loaded the image successfuly
            if(image != null)
            {
               // Create an item
               RasterImageListItem item = new RasterImageListItem();


               // Setup the item information
               item.Image = image;
               item.Text = Path.GetFileName(fileName);
               item.Page = 1;

               // To load this image in original size later
               item.FileName = fileName;

               // Add the item into RasterImageList
               imageList.Items.Add(item);
            }
         }

         imageList.EndUpdate();

      }

      private void rasterImageList_SelectedIndexChanged(object sender, EventArgs e)
      {
         // User has selected an item from the RasterImageList control.
         // Re-load the item image and show it in original size in the viewer

         // Get the selected item(s)
         RasterImageListItemCollection selectedItems = imageList.SelectedItems;
         if(selectedItems != null && selectedItems.Count == 1)
         {
            RasterImageListItem item = selectedItems[0];

            // Load the image in its original size and set it in the viewer
            viewer.Image = codecs.Load(
               item.FileName,
               0,
               CodecsLoadByteOrder.BgrOrGray,
               1,
               1);
         }
      }

      private RasterImage LoadThumbnail(string fileName)
      {
         RasterImage image = null;

         try
         {
            // See if we can load this image
            CodecsImageInfo info = codecs.GetInformation(fileName, false, 1);

            if(info.Format != RasterImageFormat.Unknown)
            {
               // Yes, calculate the thumbnail size to fit into RasterImageList.ItemImageSize
               Rectangle rc = new Rectangle(
                  0,
                  0,
                  imageList.ItemImageSize.Width,
                  imageList.ItemImageSize.Height);

               rc = RasterImageList.GetFixedAspectRatioImageRectangle(info.Width, info.Height, rc);

               // Load the thumbnail
               image = codecs.Load(
                  fileName,
                  rc.Width,
                  rc.Height,
                  24,
                  RasterSizeFlags.Resample,
                  CodecsLoadByteOrder.BgrOrGray,
                  1,
                  1);
            }
            else
               image = null;
         }
         catch
         {
            image = null;
         }
         return image;
      }
   }

   public void RasterImageList_Image()
   {
      MyForm2 form = new MyForm2();
      form.ShowDialog();
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

RasterImageListItem Class
RasterImageListItem Members