c# - WPF SelectionChanged 事件在选项卡更改之前执行操作

Question

我的 WPF 应用程序中有 SelectionChanged 事件。 i want that when the tab is change to do some action but first i want the tab to visualy change before the action starts.我正在使用后台工作人员来完成这项工作。我的代码是:

    private void Tab_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if (tab1.IsSelected)
        {
            //this line is not working
            tabcontrol.SelectedIndex = 1;
            wNetTest = new BackgroundWorker();
            wNetTest.DoWork += new DoWorkEventHandler(worker_DoWork);
            wNetTest.RunWorkerCompleted += worker_RunWorkerCompleted;
            wNetTest.WorkerReportsProgress = true;
            wNetTest.WorkerSupportsCancellation = true;
            wNetTest.RunWorkerAsync();

        }
    }

    void worker_DoWork(object sender, DoWorkEventArgs e)
    {
        //do the job
    }

Answer 1

您的问题是您的代码正在同步运行。因此，Tab_SelectionChanged 事件处理程序的每一行都将运行之前您将看到TabItem 更改。要解决此问题，您只需要异步运行长时间运行的进程。最简单的方法之一是:

private void Tab_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    if (tab1.IsSelected)
    {
        //this line is not working
        tabcontrol.SelectedIndex = 1;
        Task.Factory.StartNew(() => LongRunningMethod(parameter));

    }
}

private void LongRunningMethod(object parameter)
{
    // perform long running process here
}

parameter 输入参数是可选的...如果不需要，请将其删除。