我如何將信息從孩子班級傳遞到我的班級

Question

我有兩個類，來自WPF的主類和位於“ PersistDataToTable.Persist”內的子類“ PersistDataToTable”，我有一個循環，我想將該循環增量傳遞回主WPF類以顯示在進度欄中。 我有一個運行后台程序的方法的后台工作線程，我只是不知道如何從后台工作線程將數據返回到ReportProgress方法。

private void PersistDataToDb(object sender, RoutedEventArgs e)
    {
        worker = new BackgroundWorker();
        worker.WorkerReportsProgress = true;

        worker.DoWork += delegate(object o, DoWorkEventArgs args)
            {
                PersistDataToTable persistData = new PersistDataToTable();
                persistData.Persist(seriesId);

                worker.ReportProgress(loop incrament from persist()??);

            };

        worker.ProgressChanged += delegate(object o, ProgressChangedEventArgs args)
            { 
                int percentage = args.ProgressPercentage;
                progressBar.Value = percentage;
            };

        worker.RunWorkerAsync();
    }

Answer 1

您可以將worker.ReportProgress作為Action<Int>傳遞到您的Persist方法中，以便它更新回到您的UI

例：

private void PersistDataToDb(object sender, RoutedEventArgs e)
{
    worker = new BackgroundWorker();
    worker.WorkerReportsProgress = true;

    worker.DoWork += delegate(object o, DoWorkEventArgs args)
        {
            PersistDataToTable persistData = new PersistDataToTable();
            persistData.Persist(seriesId, worker.ReportProgress);
        };

    worker.ProgressChanged += delegate(object o, ProgressChangedEventArgs args)
        {
            int percentage = args.ProgressPercentage;
            progressBar.Value = percentage;
        };

    worker.RunWorkerAsync();
}

public class PersistDataToTable
{
    public void Persist(int seriesId, Action<int> progresscallback)
    {

        // set the progress and call the Action(worker.ReportProgress)
        for (int i = 0; i < 100; i++)
        {
            progresscallback.Invoke(i);
        }
    }
}

Answer 2

使用事件DoWork和RunWorkerComplete。 這是一個計數為10並將結果傳遞給標簽的示例：

void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    label1.Text = e.Result.ToString(); // getting the result set in DoWork
}

void worker_DoWork(object sender, DoWorkEventArgs e)
{
    int value = 0;

    for (int i = 0; i < 10; i++)
        value++;

    e.Result = value; // setting result for RunWorkerCompleted
}

有關此問題的msdn文章： http : //msdn.microsoft.com/zh-cn/library/system.componentmodel.backgroundworker.dowork.aspx