将值从BackgroundWorker DoWork传递到BackgroundWorker已完成 [英] Pass values from BackgroundWorker DoWork to BackgroundWorker Completed

问题描述

如何将值从BackgroundWorker DoWork传递给BackgroundWorker Completed?由于BackgroundWorker DoWork不会调用BackgroundWorker Completed，因此我不确定如何声明public variable以外的方法.本质上，我希望BackgroundWorker Completed通过ByVal接受BackgroundWorker DoWork中的变量.

How do I pass a value from BackgroundWorker DoWork to BackgroundWorker Completed? Since BackgroundWorker Completed is not called by BackgroundWorker DoWork I am not sure how to do this except declare a public variable. Essentially, I want BackgroundWorker Completed to accept through ByVal a variable from BackgroundWorker DoWork.

推荐答案

在声明DoWork函数时，请注意，该函数内置了一些方便的参数:

When you declare your DoWork function, note that it has some handy arguments built in :

Private Sub backgroundWorker1_DoWork(sender As Object, e As DoWorkEventArgs) _
                                                  Handles backgroundWorker1.DoWork

并注意RunWorkerCompleted处理程序的类似参数:

and also note similar arguments for the RunWorkerCompleted handler :

Private Sub backgroundWorker1_RunWorkerCompleted(ByVal sender As Object, _
                                          ByVal e As RunWorkerCompletedEventArgs) _
                                       Handles backgroundWorker1.RunWorkerCompleted

重要的是，您可以访问e.Result中的e.Result，该对象可以是任何对象，还可以访问DoWorkEventArgs中的e.Result-当方法完成时，后者将传递给前者，因此您的worker方法的末尾只需设置:

Critically, you have access to e.Result, which can be any object, in the RunWorkerCompletedEventArgs, and also e.Result in your DoWorkEventArgs - the latter is passed to the former when the method completes so at the end of your worker method just set :

e.Result = myResult

，然后在您的RunWorkerCompleted处理程序中，您也可以通过以下方式访问它:

and then in your RunWorkerCompleted handler you can access it also via :

if e.Result = (whatever) then 
    .... etc

---

参考:

RunWorkerCompletedEventArgs.结果属性:MSDN

DoWorkEventArgs.结果属性:MSDN

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