Question

我想制作一个基于线程的素数计算器。

问题是UI冻结而且没有数字发生。

代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Threading;

namespace PrimeNumbers
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        //private delegate void AddListItem(int item);
        Thread t;
        bool interrupt;
        public MainWindow()
        {
            InitializeComponent();
        }

        private void btss_Click(object sender, RoutedEventArgs e)
        {
            if (t == null)
            {
                t = new Thread(this.calculate);
                t.Start();
                btss.Content = "Stop";
            }
            else
            {
                t.Interrupt();
            }

        }

        private void calculate()
        {
            int currval = 2;
            while (!interrupt)
            {
                for (int i = 2; i < currval/2; i++)
                {
                    if (2 % i != 0)
                    {
                        AddListBoxItem(currval);

                    }
                }
                currval++;
            }
        }
        private void AddListBoxItem(int item)
        {
            if (this.lbPrimes.Dispatcher.Thread == Thread.CurrentThread)
            {
                lbPrimes.Items.Add(item.ToString());
            }
            else
            {
                lbPrimes.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal,
                new Action(
                            delegate()
                            {
                                lbPrimes.Items.Add(item.ToString());
                            }
                           ));
            }
        }

    }
}

Answer 1

删除开始你需要调用它我的意思是 “lbPrimes.Dispatcher.Invoke（..”instaed of“lbPrimes.Dispatcher.BeginInvoke（...”
这显示了数字，但是如果你想要一个正确的解决方案，你需要类似下面的代码。

/// <summary>   
/// /// Interaction logic for MainWindow.xaml   
/// /// </summary>    
public partial class MainWindow : Window
{
    //private delegate void AddListItem(int item);     
    Thread t;

    private long num = 3;
    private bool interrupt = true;
    private bool NotAPrime = false;

    public MainWindow()
    {
        InitializeComponent();
    }

    private void AddListBoxItem(int item)
    {
        lbPrimes.Dispatcher.BeginInvoke
            (DispatcherPriority.Send,
            new Action(delegate()
            {
                lbPrimes.Items.Add(item.ToString());
            }));
    }

    private void btss_Click(object sender, RoutedEventArgs e)
    {
        if (!interrupt)
        {
            interrupt = true;
            btss.Content = "Resume";
        }
        else
        {
            interrupt = false;
            btss.Content = "Stop";
            btss.Dispatcher.BeginInvoke(
                DispatcherPriority.Normal,
                new Action(calculate));
        }

    }

    public void calculate()
    {
        NotAPrime = false;

        for (long i = 3; i <= Math.Sqrt(num); i++)
        {
            if (num % i == 0)
            {
                NotAPrime = true;
                break;
            }
        }


        if (!NotAPrime)
        {
            lbPrimes.Items.Add(num.ToString());
        }

        num += 2;
        if (!interrupt)
        {
            btss.Dispatcher.BeginInvoke(
                 System.Windows.Threading.DispatcherPriority.SystemIdle,
                 new Action(this.calculate));
        }
    }
}

列表框中没有数字

1 个答案: