Leadtools.Controls Namespace > ImageViewer Object : PropertyChanged Event |
add_propertyChanged(function(sender, e)) propertyChanged.add(function(sender, e)) remove_propertyChanged(function(sender, e)) propertyChanged.remove(function(sender, e))
Most of the properties of this ImageViewer will fire the PropertyChanged event when the value changes. When this happens, the value of PropertyChangedEventArgs.PropertyName of the event data will be set to the name of the property that was changed. For example, the PropertyChangedEventArgs.PropertyName will be set to "UseDpi" when UseDpi changes and "ScrollOffset" when ScrollOffset changes.
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:
var _this = this; if (this._firstCall) { this._firstCall = false; // Subscribe to PropertyChanged event this._imageViewer.propertyChanged.add(function(sender, e) { if (e.propertyName == "flip") { var infoLabel = document.getElementById("infoLabel"); if (_this._imageViewer.flip) { infoLabel.textContent = "Image is flipped"; } else { infoLabel.textContent = "Image is not flipped"; } } }); } // Change the flip state of the image this._imageViewer.flip = !this._imageViewer.flip;
Parameter | Type | Description |
---|---|---|
sender | 'var' | The source of the event. |
e | PropertyChangedEventArgs | The event data. |