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ItemError Event (ImageViewer)

Summary

Occurs when an error happens when the viewer tries to update the item image data.

Syntax

C++

public event EventHandler<Leadtools.Controls.ImageViewerItemErrorEventArgs> ItemError

Public Event ItemError As EventHandler(Of Leadtools.Controls.ImageViewerItemErrorEventArgs)

public:  
   event EventHandler<Leadtools::Controls::ImageViewerItemErrorEventArgs^>^ ItemError

Remarks

An error might occur if the image viewer is updating the image data of any of the items asynchronously or outside direct user programmatic interaction (such as during the drop part of a drag/drop operation). These operations do not occur from the user code (drop) or occur at a later time after they have been initiated (loading images asynchronously), therefore, the user must attach a handler to the ItemError event to be able to handle these errors.

When value of ImageViewerItem.Url is set to a new value, the image viewer will use the current RasterCodecsInstance to load the image data asynchronously using RasterCodecs.LoadAsync or RasterCodecs.LoadSvgAsync. This can be trigger by any of the following:

ImageViewerItems.AddFromImageUrl is called
ImageViewerItems.InsertFromImageUrl is called
ImageViewerItems.AddFromSvgUrl is called
ImageViewerItems.InsertFromSvgUrl is called
ImageViewerItems.UpdateUrl is called
ImageViewerItem.Url is set to a new value
ImageViewer.ImageUrl is set to a new value

If an error occurs, it fires the ItemError event will fire with the following values set in ImageViewerItemErrorEventArgs:

Member	Value
Item	The item that triggered the error
Reason	ImageViewerItemChangedReason.Url
Data	Set to the instance of CodecsLoadAsyncCompletedEventArgs used internally by the viewer during LoadAsyncCompleted or LoadSvgAsyncCompleted.
Error	The exception thrown
RemoveEmptyItem	Set to true to automatically remove this item if it did not have previous data.

When an image or file system item is dragged and dropped over the viewer and System.Windows.Forms.Control.AllowDrop was set true, the viewer will try to automatically update or add a new item and load the new image data into it. An error might occur at this point and if so, the ItemError event will fire with the following values set in ImageViewerItemErrorEventArgs:

Member	Value
Item	The item that triggered the error
Reason	ImageViewerItemChangedReason.Drop
Data	Set to the instance of ImageViewerItemDragDropEventArgs being used.
Error	The exception thrown
RemoveEmptyItem	Set to true to automatically remove this item if it did not have previous data.