为什么新类中的计时器tick事件会从form1调用一次方法，并且在下一次它什么都不做的时候？

2 回答

• 0

  问题很可能是在Elapsed事件中某处发生了异常，并且Timer永远不会再次启动 . 您可以设置一个断点，并在第一次进入时查看断点，以查看它是否失败 . 或者，您可以将其编码为开始备份，无论如何：

  static void _timer_Elapsed(object sender, ElapsedEventArgs e)
  {
      _timer.Stop();
  
      try
      {
          LoadOldHtmlFiles();
          frm1.CombindedStringFix();
      }
      catch (Exception ex)
      {
          // do something (or nothing) with the exception
      }
      finally 
      {
          _timer.Start();
      }
  }
  

  ---

  由于您确认发生了跨线程异常，我建议您阅读：

  How to: Make Thread-Safe Calls to Windows Forms Controls

  这是他们的演示，以防链接被破坏：

  using System;
  using System.ComponentModel;
  using System.Threading;
  using System.Windows.Forms;
  
  namespace CrossThreadDemo
  {
      public class Form1 : Form
      {
          // This delegate enables asynchronous calls for setting 
          // the text property on a TextBox control. 
          delegate void SetTextCallback(string text);
  
          // This thread is used to demonstrate both thread-safe and 
          // unsafe ways to call a Windows Forms control. 
          private Thread demoThread = null;
  
          // This BackgroundWorker is used to demonstrate the  
          // preferred way of performing asynchronous operations. 
          private BackgroundWorker backgroundWorker1;
  
          private TextBox textBox1;
          private Button setTextUnsafeBtn;
          private Button setTextSafeBtn;
          private Button setTextBackgroundWorkerBtn;
  
          private System.ComponentModel.IContainer components = null;
  
          public Form1()
          {
              InitializeComponent();
          }
  
          protected override void Dispose(bool disposing)
          {
              if (disposing && (components != null))
              {
                  components.Dispose();
              }
              base.Dispose(disposing);
          }
  
          // This event handler creates a thread that calls a  
          // Windows Forms control in an unsafe way. 
          private void setTextUnsafeBtn_Click(
              object sender, 
              EventArgs e)
          {
              this.demoThread = 
                  new Thread(new ThreadStart(this.ThreadProcUnsafe));
  
              this.demoThread.Start();
          }
  
          // This method is executed on the worker thread and makes 
          // an unsafe call on the TextBox control. 
          private void ThreadProcUnsafe()
          {
              this.textBox1.Text = "This text was set unsafely.";
          }
  
          // This event handler creates a thread that calls a  
          // Windows Forms control in a thread-safe way. 
          private void setTextSafeBtn_Click(
              object sender, 
              EventArgs e)
          {
              this.demoThread = 
                  new Thread(new ThreadStart(this.ThreadProcSafe));
  
              this.demoThread.Start();
          }
  
          // This method is executed on the worker thread and makes 
          // a thread-safe call on the TextBox control. 
          private void ThreadProcSafe()
          {
              this.SetText("This text was set safely.");
          }
  
          // This method demonstrates a pattern for making thread-safe 
          // calls on a Windows Forms control.  
          // 
          // If the calling thread is different from the thread that 
          // created the TextBox control, this method creates a 
          // SetTextCallback and calls itself asynchronously using the 
          // Invoke method. 
          // 
          // If the calling thread is the same as the thread that created 
          // the TextBox control, the Text property is set directly.  
  
          private void SetText(string text)
          {
              // InvokeRequired required compares the thread ID of the 
              // calling thread to the thread ID of the creating thread. 
              // If these threads are different, it returns true. 
              if (this.textBox1.InvokeRequired)
              {   
                  SetTextCallback d = new SetTextCallback(SetText);
                  this.Invoke(d, new object[] { text });
              }
              else
              {
                  this.textBox1.Text = text;
              }
          }
  
          // This event handler starts the form's  
          // BackgroundWorker by calling RunWorkerAsync. 
          // 
          // The Text property of the TextBox control is set 
          // when the BackgroundWorker raises the RunWorkerCompleted 
          // event. 
          private void setTextBackgroundWorkerBtn_Click(
              object sender, 
              EventArgs e)
          {
              this.backgroundWorker1.RunWorkerAsync();
          }
  
          // This event handler sets the Text property of the TextBox 
          // control. It is called on the thread that created the  
          // TextBox control, so the call is thread-safe. 
          // 
          // BackgroundWorker is the preferred way to perform asynchronous 
          // operations. 
  
          private void backgroundWorker1_RunWorkerCompleted(
              object sender, 
              RunWorkerCompletedEventArgs e)
          {
              this.textBox1.Text = 
                  "This text was set safely by BackgroundWorker.";
          }
  
          #region Windows Form Designer generated code
  
          private void InitializeComponent()
          {
              this.textBox1 = new System.Windows.Forms.TextBox();
              this.setTextUnsafeBtn = new System.Windows.Forms.Button();
              this.setTextSafeBtn = new System.Windows.Forms.Button();
              this.setTextBackgroundWorkerBtn = new System.Windows.Forms.Button();
              this.backgroundWorker1 = new System.ComponentModel.BackgroundWorker();
              this.SuspendLayout();
              //  
              // textBox1 
              //  
              this.textBox1.Location = new System.Drawing.Point(12, 12);
              this.textBox1.Name = "textBox1";
              this.textBox1.Size = new System.Drawing.Size(240, 20);
              this.textBox1.TabIndex = 0;
              //  
              // setTextUnsafeBtn 
              //  
              this.setTextUnsafeBtn.Location = new System.Drawing.Point(15, 55);
              this.setTextUnsafeBtn.Name = "setTextUnsafeBtn";
              this.setTextUnsafeBtn.TabIndex = 1;
              this.setTextUnsafeBtn.Text = "Unsafe Call";
              this.setTextUnsafeBtn.Click += new System.EventHandler(this.setTextUnsafeBtn_Click);
              //  
              // setTextSafeBtn 
              //  
              this.setTextSafeBtn.Location = new System.Drawing.Point(96, 55);
              this.setTextSafeBtn.Name = "setTextSafeBtn";
              this.setTextSafeBtn.TabIndex = 2;
              this.setTextSafeBtn.Text = "Safe Call";
              this.setTextSafeBtn.Click += new System.EventHandler(this.setTextSafeBtn_Click);
              //  
              // setTextBackgroundWorkerBtn 
              //  
              this.setTextBackgroundWorkerBtn.Location = new System.Drawing.Point(177, 55);
              this.setTextBackgroundWorkerBtn.Name = "setTextBackgroundWorkerBtn";
              this.setTextBackgroundWorkerBtn.TabIndex = 3;
              this.setTextBackgroundWorkerBtn.Text = "Safe BW Call";
              this.setTextBackgroundWorkerBtn.Click += new System.EventHandler(this.setTextBackgroundWorkerBtn_Click);
              //  
              // backgroundWorker1 
              //  
              this.backgroundWorker1.RunWorkerCompleted += new System.ComponentModel.RunWorkerCompletedEventHandler(this.backgroundWorker1_RunWorkerCompleted);
              //  
              // Form1 
              //  
              this.ClientSize = new System.Drawing.Size(268, 96);
              this.Controls.Add(this.setTextBackgroundWorkerBtn);
              this.Controls.Add(this.setTextSafeBtn);
              this.Controls.Add(this.setTextUnsafeBtn);
              this.Controls.Add(this.textBox1);
              this.Name = "Form1";
              this.Text = "Form1";
              this.ResumeLayout(false);
              this.PerformLayout();
  
          }
  
          #endregion
  
  
          [STAThread]
          static void Main()
          {
              Application.EnableVisualStyles();
              Application.Run(new Form1());
          }
  
      }
  }
  

  回复于 2024-05-04T08:56:49+08:00
• 0

  我将尝试回答这个问题，但如果没有完整的背景，那就有点粗糙了 .

  • 我注意到在 CombindedStringFix() 方法中你看起来像是一个名为 timer3 的计时器对象 . 此计时器的名称似乎与 SaveOldHtml 类中的计时器名称不匹配，我想知道您是否有两个可能会混淆的计时器 .

  我知道不回答这个问题是不好的形式，但是如果没有更多细节/更多来源，这是我能够集合的最好的 . 任何更多的背景，我可以提供更多的帮助！

  回复于 2024-05-04T08:56:49+08:00