selectedItemsChanged Event

Summary

Occurs when any of the items inside this viewer selection state changes.

Syntax
TypeScript
JavaScript
Object.defineProperty(ImageViewer.prototype,'selectedItemsChanged', 
	get: function(), 
	set: function(value) 
) 
selectedItemsChanged: LeadEvent; 
Event Data
ParameterTypeDescription
sendervarThe source of the event.
Remarks

This event will occur when the value of ImageViewerItem.IsSelected if any of the items inside this image viewer changes. To get the selected items of the viewer:

The item selection state changes in many ways:

When any of these occur, the viewer will automatically re-renders the affected items and uses the "Selected" border, background, and text color properties for any selected items. Besides this rendering behavior, the viewer does not treat selected items any differently, and the selection state does not behave differently programmatically than any other item. Also, there is no restriction on the number of items selected: you can select none, one, or many items. For more information, refer to Image Viewer Items.

Example

This example will use the viewer as a multi-selection-enabled list of images and show how to track the current selected items.

SelectedItemsChanged.ts
ImageViewer.ts
SelectedItemsChanged.js
ImageViewer.js
SelectedItemsChanged.html
import { ImageViewer_Example } from "../ImageViewer"; 
 
export class ImageViewer_SelectedItemsChangedExample { 
   private viewerExample; 
   constructor() { 
      this.viewerExample = new ImageViewer_Example(this.run); 
   } 
 
   private run = (viewer: lt.Controls.ImageViewer) => { 
      // Clear all the images already the viewer 
      viewer.items.clear(); 
      // Use vertical view layout 
      viewer.viewLayout = new lt.Controls.ImageViewerVerticalViewLayout(); 
      // Make sure the item size is larger than the image size (thumbnails mode) 
      viewer.imageBorderThickness = 1; 
      // Change the selected item background color 
      viewer.selectedItemBackgroundColor = "lightblue"; 
 
      // Add 4 items to the viewer 
      for (let page = 1; page <= 4; page++) { 
         const item: lt.Controls.ImageViewerItem = new lt.Controls.ImageViewerItem(); 
         const imageUrl: string = "https://demo.leadtools.com/images/png/ocr" + page.toString() + ".png"; 
         item.url = imageUrl; 
         viewer.items.add(item); 
      } 
 
      // Add the interface mode to select items (multiple) 
      const selectItemsMode: lt.Controls.ImageViewerSelectItemsInteractiveMode = new lt.Controls.ImageViewerSelectItemsInteractiveMode(); 
      selectItemsMode.selectionMode = lt.Controls.ImageViewerSelectionMode.multi; 
      viewer.interactiveModes.clear(); 
      viewer.interactiveModes.add(selectItemsMode); 
 
      const output = document.getElementById("output"); 
 
      // Hook to the SelectItemsChanged event and update the text 
      viewer.selectedItemsChanged.add((sender, e) => { 
         // Get the selected items 
         let items: lt.Controls.ImageViewerItem[] = viewer.items.getSelected(); 
         let indices: number[] = []; 
         for (let i = 0; i < items.length; i++) { 
            const item: lt.Controls.ImageViewerItem = items[i]; 
            indices.push(viewer.items.indexOf(item)); 
         } 
         output.innerHTML = "Selected indices: " + indices.join(", "); 
      }); 
   } 
} 
export class ImageViewer_Example { 
   // LEADTOOLS ImageViewer to be used with this example 
   protected imageViewer: lt.Controls.ImageViewer = null; 
   // Generic state value used by the examples 
   public timesClicked: number = 0; 
 
   constructor(callback?: (viewer: lt.Controls.ImageViewer) => void) { 
      // Set the LEADTOOLS license. Replace this with your actual license file 
      lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/js/LEADTOOLSEVAL.txt", "EVAL", null); 
 
      // Create an image viewer inside the imageViewerDiv element 
      const imageViewerDiv = document.getElementById("imageViewerDiv"); 
      const createOptions: lt.Controls.ImageViewerCreateOptions = new lt.Controls.ImageViewerCreateOptions(imageViewerDiv); 
      this.imageViewer = new lt.Controls.ImageViewer(createOptions); 
      this.imageViewer.viewVerticalAlignment = lt.Controls.ControlAlignment.center; 
      this.imageViewer.viewHorizontalAlignment = lt.Controls.ControlAlignment.center; 
      this.imageViewer.autoCreateCanvas = true; 
 
      // Add Pan/Zoom interactive mode 
      // Click and drag to pan, CTRL-Click and drag to zoom in and out 
      this.imageViewer.interactiveModes.add(new lt.Controls.ImageViewerPanZoomInteractiveMode()); 
 
      // Load an image 
      this.imageViewer.imageUrl = "https://demo.leadtools.com/images/jpeg/cannon.jpg"; 
 
      this.imageViewer.zoom(lt.Controls.ControlSizeMode.fit, .9, this.imageViewer.defaultZoomOrigin); 
 
      const exampleButton = document.getElementById("exampleButton"); 
      exampleButton.addEventListener("click", () => { 
         this.timesClicked++; 
         // Run the example 
         if (callback) 
            callback(this.imageViewer); 
      }); 
   } 
} 
import { ImageViewer_Example } from "../ImageViewer"; 
 
export class ImageViewer_SelectedItemsChangedExample { 
   viewerExample; 
   constructor() { 
      this.viewerExample = new ImageViewer_Example(this.run); 
   } 
 
   run = (viewer) => { 
      // Clear all the images already the viewer 
      viewer.items.clear(); 
      // Use vertical view layout 
      viewer.viewLayout = new lt.Controls.ImageViewerVerticalViewLayout(); 
      // Make sure the item size is larger than the image size (thumbnails mode) 
      viewer.imageBorderThickness = 1; 
      // Change the selected item background color 
      viewer.selectedItemBackgroundColor = "lightblue"; 
 
      // Add 4 items to the viewer 
      for (let page = 1; page <= 4; page++) { 
         const item = new lt.Controls.ImageViewerItem(); 
         const imageUrl = "https://demo.leadtools.com/images/png/ocr" + page.toString() + ".png"; 
         item.url = imageUrl; 
         viewer.items.add(item); 
      } 
 
      // Add the interface mode to select items (multiple) 
      const selectItemsMode = new lt.Controls.ImageViewerSelectItemsInteractiveMode(); 
      selectItemsMode.selectionMode = lt.Controls.ImageViewerSelectionMode.multi; 
      viewer.interactiveModes.clear(); 
      viewer.interactiveModes.add(selectItemsMode); 
 
      const output = document.getElementById("output"); 
 
      // Hook to the SelectItemsChanged event and update the text 
      viewer.selectedItemsChanged.add((sender, e) => { 
         // Get the selected items 
         let items = viewer.items.getSelected(); 
         let indices = []; 
         for (let i = 0; i < items.length; i++) { 
            const item = items[i]; 
            indices.push(viewer.items.indexOf(item)); 
         } 
         output.innerHTML = "Selected indices: " + indices.join(", "); 
      }); 
   } 
} 
export class ImageViewer_Example { 
   // LEADTOOLS ImageViewer to be used with this example 
   imageViewer = null; 
   // Generic state value used by the examples 
   timesClicked = 0; 
 
   constructor(callback) { 
      // Set the LEADTOOLS license. Replace this with your actual license file 
      lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/js/LEADTOOLSEVAL.txt", "EVAL", null); 
 
      // Create an image viewer inside the imageViewerDiv element 
      const imageViewerDiv = document.getElementById("imageViewerDiv"); 
      const createOptions = new lt.Controls.ImageViewerCreateOptions(imageViewerDiv); 
      this.imageViewer = new lt.Controls.ImageViewer(createOptions); 
      this.imageViewer.viewVerticalAlignment = lt.Controls.ControlAlignment.center; 
      this.imageViewer.viewHorizontalAlignment = lt.Controls.ControlAlignment.center; 
      this.imageViewer.autoCreateCanvas = true; 
 
      // Add Pan/Zoom interactive mode 
      // Click and drag to pan, CTRL-Click and drag to zoom in and out 
      this.imageViewer.interactiveModes.add(new lt.Controls.ImageViewerPanZoomInteractiveMode()); 
 
      // Load an image 
      this.imageViewer.imageUrl = "https://demo.leadtools.com/images/jpeg/cannon.jpg"; 
 
      this.imageViewer.zoom(lt.Controls.ControlSizeMode.fit, .9, this.imageViewer.defaultZoomOrigin); 
 
      const exampleButton = document.getElementById("exampleButton"); 
      exampleButton.addEventListener("click", () => { 
         this.timesClicked++; 
         // Run the example 
         if (callback) 
            callback(this.imageViewer); 
      }); 
   } 
} 
<!doctype html> 
<html lang="en"> 
<title>Controls Example | SelectedItemsChanged</title> 
 
<head> 
   <script src="https://code.jquery.com/jquery-2.2.4.min.js" 
      integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44=" crossorigin="anonymous"></script> 
 
   <script src="../../LT/Leadtools.js"></script> 
   <script src="../../LT/Leadtools.Controls.js"></script> 
   <script src="../../LT/Leadtools.Annotations.Engine.js"></script> 
   <script src="../../LT/Leadtools.Annotations.Designers.js"></script> 
   <script src="../../LT/Leadtools.Annotations.Rendering.Javascript.js"></script> 
   <script src="../../LT/Leadtools.Annotations.Automation.js"></script> 
   <script src="../../LT/Leadtools.ImageProcessing.Main.js"></script> 
   <script src="../../LT/Leadtools.ImageProcessing.Color.js"></script> 
   <script src="../../LT/Leadtools.ImageProcessing.Core.js"></script> 
   <script src="../../LT/Leadtools.ImageProcessing.Effects.js"></script> 
   <script src="../../LT/Leadtools.Document.js"></script> 
   <script src="../../LT/Leadtools.Document.Viewer.js"></script> 
   <style> 
      body { 
         font-family: 'Segoe UI', sans-serif; 
      } 
 
      #imageViewerDiv { 
         border: 1px solid #888; 
         width: 500px; 
         height: 500px; 
         background-color: #eee; 
      } 
   </style> 
 
   <!-- All demo files are bundled and appended to the window --> 
   <script src="../../bundle.js" type="text/javascript"></script> 
</head> 
 
<body> 
   <p>Press and drag on the image to pan.</p> 
   <p>Hold down the control key and press and drag on the image or pinch with two fingers to zoom in and out.</p> 
   <div> 
      <button type="button" id="exampleButton">Run Example</button> 
   </div> 
   <div id="imageViewerDiv"></div> 
   <div id="output"></div> 
</body> 
 
<script> 
   window.onload = () => { 
      const example = new window.examples.ImageViewer.SelectedItemsChanged(); 
 
   }; 
</script> 
</html> 
Requirements

Target Platforms

Help Version 22.0.2021.9.24
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© 1991-2022 LEAD Technologies, Inc. All Rights Reserved.

Leadtools.Controls Assembly
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2022 LEAD Technologies, Inc. All Rights Reserved.