IAsyncInfo
IAsyncInfo
IAsyncInfo
IAsyncInfo
Interface
Definition
Supports asynchronous actions and operations. IAsyncInfo is a base interface for IAsyncAction, IAsyncActionWithProgress;, IAsyncOperation; and IAsyncOperationWithProgress;, each of which support combinations of return type and progress for an asynchronous method.
public : interface IAsyncInfopublic interface IAsyncInfoPublic Interface IAsyncInfo// You can use this interface in JavaScript.
- Attributes
| Device family |
Windows 10 (introduced v10.0.10240.0)
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| API contract |
Windows.Foundation.FoundationContract (introduced v1)
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Remarks
IAsyncInfo is an inherited interface for each of the 4 Windows Runtime interfaces that are used for asynchronous method support. These are:
When you use asynchronous methods in your app code, you usually don't see any of these interfaces as the return value. That's because you almost always use the language-specific awaitable syntax, which handles the interfaces internally. For more info, see Asynchronous programming, or one of the language-specific guides to Windows Runtime asynchronous programming (Call asynchronous APIs in C# or Visual Basic, C++, JavaScript).
For most app code, it's uncommon to use IAsyncInfo as an API even if you don't use an awaitable syntax. Each of the languages has extension points that are generally easier to use than is the Windows Runtime@Windows.Foundation.IAsyncInfo?text=IAsyncInfo interface. JavaScript has the then/done syntax. .NET has the AsTask extension method, and once the IAsyncAction is converted to a Task, it's easier to cancel, get notification on completion, and so on. For C++/CX, you can wrap the calls using the Concurrency runtime. In other words, IAsyncInfo is runtime-level infrastructure, which each of the languages use as a framework to support awaitable syntax in their own way.
If you're implementing a custom action or custom operation (an advanced scenario) don't implement IAsyncAction directly. Implement one of the 4 interfaces previously listed instead.
Properties
ErrorCode ErrorCode ErrorCode ErrorCode
Gets a string that describes an error condition of the asynchronous operation.
public : HResult ErrorCode { get; }public Exception ErrorCode { get; }Public ReadOnly Property ErrorCode As Exception// You can use this property in JavaScript.
- Value
- HResult Exception Exception Exception
The error string.
Remarks
Error codes are exposed as different types depending on the programming language you are using. Similarly, each language has different techniques for wrapping asynchronous method calls so that error conditions or cancellation can be handled. For more info see one of these topics:
- See Also
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Id Id Id Id
Gets the handle of the asynchronous operation.
public : unsigned int Id { get; }public uint Id { get; }Public ReadOnly Property Id As uint// You can use this property in JavaScript.
- Value
- unsigned int uint uint uint
The handle of the asynchronous operation.
Status Status Status Status
Gets a value that indicates the status of the asynchronous operation.
public : AsyncStatus Status { get; }public AsyncStatus Status { get; }Public ReadOnly Property Status As AsyncStatus// You can use this property in JavaScript.
The status of the operation, as a value of the enumeration. A value of Completed indicates that the method has returned. The Started value represents a transition state before any of the other 3 final results (Completed, Error, Canceled) can be determined by the method's invocation.
- See Also
Methods
Cancel() Cancel() Cancel() Cancel()
Cancels the asynchronous operation.
public : void Cancel()public void Cancel()Public Function Cancel() As void// You can use this method in JavaScript.
Close() Close() Close() Close()
Closes the asynchronous operation.
public : void Close()public void Close()Public Function Close() As void// You can use this method in JavaScript.
Remarks
Calling this method indicates that you have finished with the results of the operation. After calling Close, do not call the GetResults method again (each of the 4 IAsyncInfo derived interfaces have their own implementation of GetResults.)
- See Also