PropertyChanged Event

Summary

Occurs when a property value in this ImageViewer changes.

Syntax

C++/CLI

public event PropertyChangedEventHandler PropertyChanged

public:  
   event System::ComponentModel::PropertyChangedEventHandler^ PropertyChanged

Remarks

Most of the properties of this ImageViewer will fire the PropertyChanged event when the value changes. When this happens, the value of System.ComponentModel.PropertyChangedEventArgs.PropertyName of the event data will be set to the name of the property that was changed. For example, the System.ComponentModel.PropertyChangedEventArgs.PropertyName will be set to "UseDpi" when UseDpi changes and "ScrollOffset" when ScrollOffset changes.

Example

Run the demo and now as you click the Example button, the label is updated.

Start with the ImageViewer example, remove all the code inside the example function (search for the "// TODO: add example code here" comment) and insert the following code:

using Leadtools; 
using Leadtools.Controls; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
 
public ImageViewerForm _form = new ImageViewerForm(); 
public ImageViewer _imageViewer; 
 
public void ImageViewerPropertyChangedExample() 
{ 
   // Get the Form's ImageViewer control 
   _imageViewer = _form.ImageViewer; 
 
   // Load an image 
   using (var codecs = new RasterCodecs()) 
      _imageViewer.Image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "cannon.jpg")); 
 
   // Set Zoom 
   _imageViewer.Zoom(ControlSizeMode.Fit, 1, _imageViewer.DefaultZoomOrigin); 
 
   // Subscribe to PropertyChanged event 
   _imageViewer.PropertyChanged += (sender, e) => 
   { 
      if (e.PropertyName == "Flip") 
      { 
         if (_imageViewer.Flip) 
            _form.Text = "Image is flipped"; 
         else 
            _form.Text = "Image is not flipped"; 
      } 
   }; 
 
   // Change the flip state of the image 
   _imageViewer.Flip = !_imageViewer.Flip; 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
}

Event Data

Parameter	Type	Description
sender	object	The source of the event.
e	System.ComponentModel.PropertyChangedEventArgs	The event data.

Requirements

Target Platforms

Reference

ImageViewer Class

ImageViewer Members

Leadtools.Controls Namespace

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Help Version 23.0.2024.2.29

Leadtools.Controls Assembly

Introduction

Getting Started

Namespaces

Leadtools.Controls Namespace

Assemblies