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AsyncCodeActivity Class

Manages asynchronous code activity execution from start to completion. This is an abstract class.

Namespace:  System.Activities
Assembly:  System.Activities (in System.Activities.dll)

public abstract class AsyncCodeActivity : Activity

The AsyncCodeActivity type exposes the following members.

  NameDescription
Protected methodAsyncCodeActivityCreates a new instance of the AsyncCodeActivity class.
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  NameDescription
Protected propertyCacheIdGets the identifier of the cache that is unique within the scope of the workflow definition. (Inherited from Activity.)
Protected propertyConstraintsGets a collection of Constraint activities that can be configured to provide validation for the Activity. (Inherited from Activity.)
Public propertyDisplayNameGets or sets an optional friendly name that is used for debugging, validation, exception handling, and tracking. (Inherited from Activity.)
Public propertyIdGets an identifier that is unique in the scope of the workflow definition. (Inherited from Activity.)
Protected propertyImplementationGets null or throws an error when there is an attempt to set the value of this property. (Overrides Activity.Implementation.)
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  NameDescription
Protected methodBeginExecuteWhen implemented in a derived class and using the specified execution context, callback method, and user state, enqueues an asynchronous activity in a run-time workflow.
Protected methodCacheMetadata(ActivityMetadata)Not implemented. Use CacheMetadata(CodeActivityMetadata) instead. (Overrides Activity.CacheMetadata(ActivityMetadata).)
Protected methodCacheMetadata(CodeActivityMetadata)Serves as a virtual method and converts information obtained by cache reflection into arguments for an asynchronous activity.
Protected methodCancelWhen implemented in a derived class and using the specified execution environment information, notifies the workflow runtime that the asynchronous activity operation has reached an early completion. Serves as a virtual method.
Protected methodEndExecuteWhen implemented in a derived class and using the specified execution environment information, notifies the workflow runtime that the associated asynchronous activity operation has completed.
Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodShouldSerializeDisplayNameIndicates whether the DisplayName property should be serialized. (Inherited from Activity.)
Public methodToStringReturns a String that contains the Id and DisplayName of the Activity. (Inherited from Activity.)
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The following example shows how to derive a class from AsyncCodeActivity to create a custom activity.


public sealed class FileWriter : AsyncCodeActivity
{
    public FileWriter()
        : base() 
    { 
    }
    protected override IAsyncResult BeginExecute(AsyncCodeActivityContext context, AsyncCallback callback, object state)
    {
        string tempFileName = Path.GetTempFileName();
        Console.WriteLine("Writing to file: " + tempFileName);

        FileStream file = File.Open(tempFileName, FileMode.Create);

        context.UserState = file;

        byte[] bytes = UnicodeEncoding.Unicode.GetBytes("123456789");
        return file.BeginWrite(bytes, 0, bytes.Length, callback, state);
    }
    protected override void EndExecute(AsyncCodeActivityContext context, IAsyncResult result)
    {
        FileStream file = (FileStream)context.UserState;

        try
        {
            file.EndWrite(result);
            file.Flush();
        }
        finally
        {
            file.Close();
        }
    }
}


.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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