Image Property (RasterImageListItem)

The image associated with this RasterImageListItem object.

Syntax

C#
Visual Basic
Objective-C
Java
C++

public RasterImage Image {get; set;}

'Declaration
 
Public Property Image As RasterImage

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

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

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

C#
Visual Basic
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Imports Leadtools.WinForms
Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Drawing

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

using Leadtools.WinForms;
using Leadtools;
using Leadtools.Codecs;
using Leadtools.Drawing;

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

Reference

RasterImageListItem Class
RasterImageListItem Members