Question

我想为WPF应用程序中的连续进度条分配一个新线程，以便在点击UI按钮后它会持续运行，直到我收到服务响应。

我做了类似下面的代码，但是进度条（MclarenServerCecksProgressBar）似乎根本不起作用

MclarenServerCecksProgressBar.Visibility = Visibility.Visible;
var uiThread = new Thread(() =>
{
progressBarDisptacher = MclarenServerCecksProgressBar.Dispatcher;


// allowing the main UI thread to proceed 
System.Windows.Threading.Dispatcher.Run();    
});
uiThread.SetApartmentState(ApartmentState.STA);
uiThread.IsBackground = true;
uiThread.Start();      
string[] servicesss = getServices(servername,server);
DataTable dtd = esd.getListOfServices(servername, usrid.Text.ToString(),   
userpass.Password.ToString(), servicesss);
MclarenServerCecksProgressBar.Visibility = Visibility.Hidden;

请安排建议我实现这一点，任何其他指示都会有所帮助。

Answer 1

我不知道代码进度条值集的方式。另外我不太明白为什么你用这个黑客攻击线程。如果我理解你的问题，我就举例说明了我如何使用进度条进行此操作。

<Window x:Class="WpfApplication5.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow"
    Height="350"
    Width="525">
<Grid>
    <ProgressBar Height="10"
             HorizontalAlignment="Left"
             Margin="12,12,0,0"
             Name="progressBar1"
             VerticalAlignment="Top"
             Width="100"
             Visibility="Hidden" />
    <Button Content="Button"
        Height="23"
        HorizontalAlignment="Left"
        Margin="30,54,0,0"
        Name="button1"
        VerticalAlignment="Top"
        Width="75"
        Click="button1_Click" />
</Grid>
</Window>

using System;
using System.Threading;
using System.Windows;

namespace WpfApplication5 {
    public partial class MainWindow : Window {
        public MainWindow() {
            InitializeComponent();
        }

        void button1_Click(object sender, RoutedEventArgs e) {
            progressBar1.Visibility = Visibility.Visible;
            Action method = () => {
                Action<int> method2 = (val) => {
                    progressBar1.Value = val;
                };
                for (int i = 0 ; i < 10 ; i++) {
                    Thread.Sleep(500);
                    Dispatcher.BeginInvoke(method2, i * 10);
                }
                Action method3 = () => {
                    progressBar1.Visibility = Visibility.Hidden;
                };
                Dispatcher.BeginInvoke(method3);
            };
            method.BeginInvoke(null, null);
        }
    }
}

Answer 2

最后，我通过做一些技巧实现了这一目标。我已经使用了DependencyProperty和Dispatacher的委托更新了Progressbar，经过多次尝试，这对我有用，看看我在下面做的代码

private delegate void UpdateProgressBarDelegate(
    System.Windows.DependencyProperty dp, Object value);

private void startProgessBar(string controlname)
{
    MclarenServerCecksProgressBar.Visibility = Visibility.Visible;


    //Stores the value of the ProgressBar

    //Create a new instance of our ProgressBar Delegate that points
    // to the ProgressBar's SetValue method.
    UpdateProgressBarDelegate updatePbDelegate =
        new UpdateProgressBarDelegate(MclarenServerCecksProgressBar.SetValue);
    bool _status = true;
    int flag = 0;
    double value = 0;

    do
    {

        /*Update the Value of the ProgressBar: */

        Dispatcher.Invoke(updatePbDelegate,
            System.Windows.Threading.DispatcherPriority.Background,
            new object[] { System.Windows.Controls.ProgressBar.ValueProperty, value });


                if (flag == 0)
                {
                    flag == 1
                    _status = processesServices(controlname);
                }
                if (_status == false)
                {
                    MclarenServerCecksProgressBar.Visibility = Visibility.Hidden;
                }
    }
    while (_status);
}

无论如何修复它可能都是脏的，我一直在寻找运行progessbar，直到我收到一个函数的响应，任何其他改进这种方式的建议都会很受欢迎。欢迎任何建议和帮助，以改善这一点。

Answer 3

WPF UI只有一个可用于通信的UI线程 - 调度程序线程。您可以在任何您喜欢的线程上完成所有后台任务，只要与UI对象交互的调用是通过UI调度程序完成的。通过此调度程序发送调用是一项常见任务，因此在每个WPF对象上都提供了Dispatcher属性。

我会像这样解决问题：

    private void button2_Click(object sender, RoutedEventArgs e)
    {
        // Currently running on the WPF thread so the WPF property can be set directly
        this.progressBar1.Visibility = System.Windows.Visibility.Visible;

        // Create a new thread to do the long running task
        Thread worker = new Thread(() =>
        {
            WebService.DoSomethingThatTakesAges();

            // When the above call has completed, update the UI on its dispatcher thread
            this.progressBar1.Dispatcher.BeginInvoke(new Action(() =>
                {
                    this.progressBar1.Visibility = System.Windows.Visibility.Hidden;
                }));
        });

        worker.Start();
    }

最好使用System.Threading.Tasks命名空间用TaskSchedulers创建Tasks而不是直接创建线程，但原理是相同的。

想要在UI中持续运行Progress-Bar，直到我们收到服务响应

3 个答案: