語言

AsyncCodeActivity.BeginExecute 方法

定義

命名空間:
System.Activities
組件:
System.Activities.dll

當在衍生類別中實作，並使用指定的執行上下文、回調方法及使用者狀態時，會將非同步活動置於執行時工作流程中。

protected:
 abstract IAsyncResult ^ BeginExecute(System::Activities::AsyncCodeActivityContext ^ context, AsyncCallback ^ callback, System::Object ^ state);
protected abstract IAsyncResult BeginExecute(System.Activities.AsyncCodeActivityContext context, AsyncCallback callback, object state);
abstract member BeginExecute : System.Activities.AsyncCodeActivityContext * AsyncCallback * obj -> IAsyncResult
Protected MustOverride Function BeginExecute (context As AsyncCodeActivityContext, callback As AsyncCallback, state As Object) As IAsyncResult

參數

context
AsyncCodeActivityContext

定義執行環境的 AsyncCodeActivity資訊。

callback
AsyncCallback

非同步活動與完成通知發生後，該方法將被呼叫。

state
Object

一個為非同步活動實例儲存變數資訊的物件。

傳回

IAsyncResult

為非同步活動的實例儲存變數資訊的物件。

範例

以下範例展示了如何在自訂活動中覆寫該 BeginExecute 方法。

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);
}

適用於