如何将信息从子类传递给我的主类答案

【问题标题】：how do I pass info to my main class from a child class如何将信息从子类传递给我的主类
【发布时间】：2013-08-06 07:47:58
【问题描述】：

我有两个类，来自 WPF 的主类和在“PersistDataToTable.Persist”内称为“PersistDataToTable”的子类我有一个循环，我想将该循环增量传递回主 WPF 类以显示在进度条中. 我有一个后台工作线程运行命中循环的方法，我只是不知道如何将数据从后台工作线程返回给 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();
    }

【问题讨论】：

标签： c# wpf delegates

【解决方案1】：

您可以将 worker.ReportProgress 作为 Action<Int> 传递到您的 Persist 方法中，以便它更新回您的 UI

例子：

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);
        }
    }
}

【讨论】：

【解决方案2】：

使用事件 DoWork 和 RunWorkerComplete。这是一个计数到 10 并将结果传递给标签的示例：

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
}

关于这个的msdn文章：http://msdn.microsoft.com/en-us/library/system.componentmodel.backgroundworker.dowork.aspx

【讨论】：