Question

没有do循环，我的代码运行正常。只要我将它放在do或while循环中，代码就无法更新颜色状态。任何的想法？根据我从互联网上收集的内容，我的循环写得正确。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Net.NetworkInformation;
using System.Threading;



namespace SystemsUpDown
{
    public partial class MainForm : Form
    {

        public MainForm()
        {
            InitializeComponent();
        }

        bool ContinuePing = false;


        private void QuitButton_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void StartButton_Click_1(object sender, EventArgs e)
        {
            Ping ping = new Ping();
            ContinuePing = true;
            do
            {
                try ///ping google
                {
                    PingReply reply = ping.Send("8.8.8.8");

                    if (reply.Status == IPStatus.Success)
                    {
                        GoogleStatusLabel.BackColor = Color.Green;
                    }

                }
                catch
                {
                    GoogleStatusLabel.BackColor = Color.Red;
                }

                try ///ping Yahoo!
                {
                    PingReply reply = ping.Send("www.yahoo.com");

                    if (reply.Status == IPStatus.Success)
                    {
                        YahooStatusLabel.BackColor = Color.Green;
                    }

                }
                catch
                {
                    YahooStatusLabel.BackColor = Color.Red;
                }

                try ///ping Reddit.com
                {
                    PingReply reply = ping.Send("www.reddit.com");

                    if (reply.Status == IPStatus.Success)
                    {
                        RedditStatusLabel.BackColor = Color.Green;
                    }

                }
                catch
                {
                    RedditStatusLabel.BackColor = Color.Red;
                }

                try ///ping Chive
                {
                    PingReply reply = ping.Send("www.chive.com");

                    if (reply.Status == IPStatus.Success)
                    {
                        ChiveStatusLabel.BackColor = Color.Green;
                    }

                }
                catch
                {
                    ChiveStatusLabel.BackColor = Color.Red;
                }

                try ///ping CNN
                {
                    PingReply reply = ping.Send("www.cnn.com");

                    if (reply.Status == IPStatus.Success)
                    {
                        CNNStatusLabel.BackColor = Color.Green;
                    }

                }
                catch
                {
                    CNNStatusLabel.BackColor = Color.Red;
                }

            } while (ContinuePing);

        }

        private void StopButton_Click(object sender, EventArgs e)
        {
            GoogleStatusLabel.BackColor = Color.Yellow;
            ChiveStatusLabel.BackColor = Color.Yellow;
            CNNStatusLabel.BackColor = Color.Yellow;
            RedditStatusLabel.BackColor = Color.Yellow;
            YahooStatusLabel.BackColor = Color.Yellow;
            ContinuePing = false;

        }
    }
}

Answer 1

更改颜色后尝试强制刷新标签：

GoogleStatusLabel.Refresh();

Answer 2

这可能是因为循环运行得足够快，因此更新无法理解。

尝试在循环中添加一些睡眠，如

//Sleep for two seconds. You can add this at end of loop.
//Or, sleep for 2 secs after pinging one site. 
// 2000 miliseconds = 2 seconds.
System.Threading.Thread.Sleep(2000);

然后检查。

我建议您使用 BackgroundWorker 。因为主线程中的while循环将挂起主窗口窗体。

BackgroundWorker 适用于对窗体控件进行此类定期更新，以便主窗口不会挂起。请参考以下链接 - https://msdn.microsoft.com/en-us/library/cc221403(v=vs.95).aspx

Answer 3

您的进程在与UI线程不同的线程上持续运行，没有时间更新UI项目。

使用Update / Refresh强制UI更新一些时间，或使用sleep让UI线程有一些时间

Answer 4

使用[ ["a",1,4,1], ["b",2], ["c",3,3,2], ["d",2], ["x",5,1], ["f",3], ["o",7] ]标记Click（）处理程序，然后将循环放入带有匿名委托的Dim Consulta As New OleDb.OleDbDataAdapter("Select m.idMedicos, m.Nombre, m.Apellido, h.idHistorial, h.CedulaP, r.*, rm.*, me.Nombre, me.Tipo, me.Administracion FROM (((Medicos m INNER JOIN Historial h ON m.idMedicos = h.idMedicos ) INNER JOIN Recetas r ON r.idHistorial = h.idHistorial ) INNER JOIN RecetaMedica rm ON rm.idReceta = r.idReceta ) INNER JOIN Medicamentos me ON me.idMedicamento = rm.idMedicamento WHERE h.CedulaP ='" + dato + "'", conexion)。使用async更新用户界面，我在下面使用辅助方法完成了该操作：

await Task.Run()

为什么我的循环不允许我的标签颜色改变？

4 个答案: