Object Model
Syntax
| Visual Basic (Declaration) | |
|---|---|
Public Class CodecsGetInformationAsyncCompletedEventArgs Inherits CodecsAsyncCompletedEventArgs | |
| Visual Basic (Usage) |  Copy Code |
|---|---|
Dim instance As CodecsGetInformationAsyncCompletedEventArgs | |
| C# | |
|---|---|
public class CodecsGetInformationAsyncCompletedEventArgs : CodecsAsyncCompletedEventArgs | |
| C++/CLI | |
|---|---|
public ref class CodecsGetInformationAsyncCompletedEventArgs : public CodecsAsyncCompletedEventArgs | |
Example
Remarks
The RasterCodecs class supports getting information on image files asynchronously using the RasterCodecs.GetInformationAsync methods. When calling any of these methods, the caller thread will not be blocked and the method will return instantly with an instance CodecsImageInfo that is in a loading status (CodecsImageInfo.IsLoading set to true). You should not use the other properties of this object while the object is in loading status.
When the RasterCodecs object finishes getting the information on the file, the various properties of the CodecsImageInfo will be populated with the image file information and the CodecsImageInfo.IsLoading property will be set to false.
It is recommended that you do not poll for the CodecsImageInfo.IsLoading property to check when the image information has been collected, instead, subscribe to the RasterCodecs.GetInformationAsyncCompleted event to get notification on when the RasterCodecs.GetInformationAsync operation is completed and if any errors occurred.
The RasterCodecs.GetInformationAsyncCompleted event data will also contain the same object returned from RasterCodecs.GetInformationAsync so you do not have to keep the original object in your application.
The RasterCodecs.GetInformationAsyncCompleted event use data argument object of type CodecsGetInformationAsyncCompletedEventArgs. This class contains the following properties:
| Property | Description |
|---|---|
| Uri, Stream and FileName |
Contains the URI, stream or file name passed to the method that initialized this asynchronous operation. Only one of these properties can be a valid value (not a null reference) at any time The property that contains a valid reference depends on what version of RasterCodecs.GetInformationAsync method has been called. For example, if RasterCodecs.GetInformationAsync(Uri uri, bool totalPages, int pageNumberobject, object userState) is being called, the CodecsAsyncCompletedEventArgs.Uri will contain the same URI passed to the method while CodecsAsyncCompletedEventArgs.Stream and CodecsAsyncCompletedEventArgs.FileName will both be null. If RasterCodecs.GetInformationAsync(string fileName, bool totalPages, int pageNumberobject, object userState) is being called, the CodecsAsyncCompletedEventArgs.FileName will contain the same file name string value passed to the method while CodecsAsyncCompletedEventArgs.Uri and CodecsAsyncCompletedEventArgs.Stream will both be null and so on. |
| Info |
Contains the CodecsImageInfo class instance that contains the information about the image file. This instance is the same object returned from the RasterCodecs.GetInformationAsync method. While the asynchronous operation is running, the value of the CodecsImageInfo.IsLoading will be true indicating that the object is being populated with the information and should not be used. Whe the asynchronous operation compelets, the RasterCodecs.GetInformationAsyncCompleted event will fire and Info will contain the final and ready to use object. If an error occurs, this property will be set to null and the object is disposed internally by the toolkit. |
| Error |
Contains any errors that might have occured during the asynchronous operation. You musg check this value when the RasterCodecs.GetInformationAsyncCompleted event fires and make sure it does not contain a valid System.Exception object. |
| Cancelled |
Contains a value indicating whether an asynchronous operation has been canceled. For example, by calling RasterCodecs.CancelAsync when using RasterCodecs.GetInformationAsync with a URL |
Inheritance Hierarchy
System.Object
System.EventArgs
System.ComponentModel.AsyncCompletedEventArgs
Leadtools.Codecs.CodecsAsyncCompletedEventArgs
Leadtools.Codecs.CodecsGetInformationAsyncCompletedEventArgs
Requirements
Target Platforms: Silverlight, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7, MAC OS/X (Intel Only)