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Represents an asynchronous action. This is the return type for many Windows Runtime asynchronous methods that don't have a result object, and don't report ongoing progress.
public interface class IAsyncAction : IAsyncInfo
/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.FoundationContract, 65536)] /// [Windows.Foundation.Metadata.Guid(1516535814, 33850, 19881, 134, 91, 157, 38, 229, 223, 173, 123)] struct IAsyncAction : IAsyncInfo
[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.FoundationContract), 65536)] [Windows.Foundation.Metadata.Guid(1516535814, 33850, 19881, 134, 91, 157, 38, 229, 223, 173, 123)] public interface IAsyncAction : IAsyncInfo
Public Interface IAsyncAction Implements IAsyncInfo
Windows 10 (introduced in 10.0.10240.0)
Windows.Foundation.FoundationContract (introduced in v1.0)
IAsyncAction is the return type for all Windows Runtime asynchronous methods that don't communicate a result object, or ongoing progress. This constitutes over 300 different Windows Runtime APIs. APIs that do report progress (but don't have a result) use another interface, IAsyncActionWithProgress<TProgress>.
Instead of using IAsyncAction, some Windows Runtime asynchronous methods use custom action types (which might have "Operation" rather than "Action" in their name). For example, SignOutUserOperation is a Windows Runtime type that implements IAsyncAction. The SignOutUserOperation type is then used as the custom action return type for the SignOutUserAsync method.
C++/WinRT extension functions
Extension functions exist on the C++/WinRT projection types for certain Windows Runtime APIs. For example, winrt::Windows::Foundation::IAsyncAction is the C++/WinRT projection type for IAsyncAction. The extension functions aren't part of the application binary interface (ABI) surface of the actual Windows Runtime types, so they're not listed as members of the Windows Runtime APIs. But you can call them from within any C++/WinRT project. See C++/WinRT functions that extend Windows Runtime APIs.
void get() const;
Waits synchronously for the action to complete. Throws a corresponding exception if the action is canceled, or enters an error state. You mustn't call it from a single-threaded apartment. For more info, and code examples showing how to call get, see Write a coroutine.
AsyncStatus wait_for(TimeSpan const& timeout) const;
Waits synchronously for the action to complete, or for the specified timeout. Returns the state of the IAsyncAction, or AsyncStatus::Started if the timeout elapsed. If the action didn't time out, then call GetResults to obtain the results of the action. For more info, and code examples showing how to call wait_for, see Asynchronous timeouts made easy.
Notes to implementers
As with calling the existing methods, there are language-specific ways to define asynchronous methods that don't use IAsyncInfo directly. If writing code using .NET, your method can return a Task. For C++/CX, you can use the Concurrency runtime. However, if you're defining a component, you can use Task/task internally but you must return one of the Windows Runtime interfaces for your public methods. The language-specific asynchronous support types (and many other language-specific types you might conventionally use in code) can't be used for the public surface area of a Windows Runtime component.
Gets or sets the method that handles the action completed notification.
Gets a string that describes an error condition of the asynchronous operation.(Inherited from IAsyncInfo)
Gets the handle of the asynchronous operation.(Inherited from IAsyncInfo)
Gets a value that indicates the status of the asynchronous operation.(Inherited from IAsyncInfo)
Cancels the asynchronous operation.(Inherited from IAsyncInfo)
Closes the asynchronous operation.(Inherited from IAsyncInfo)
Returns the results of the action.
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