c#-跨執行緒控制元件訪問問題

新手最近遇到這樣的問題: a執行緒去訪問b執行緒的控制元件,編譯器報錯。在網上找了一下解決方案，和大家分享下。

解決方法有3種:
1, 不安全的方法: 將 Control.CheckForIllegalCrossThreadCalls 設定為false (.net1.0中沒有)
2,安全的方法:　非同步委託
3, 安全的方法: 就是使用BackgroundWorker來替代你自己建立的執行緒(.net1.0中沒有)

主要說下第二種方法，例項程式碼：

<!--

Code highlighting produced by Actipro CodeHighlighter (freeware)
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--&gt 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.";
         }

          Windows Form Designer generated code


         [STAThread]
         static void Main()
          {
             Application.EnableVisualStyles();
             Application.Run(new Form1());
         }

     }
}

來自 “ ITPUB部落格 ” ，連結：http://blog.itpub.net/12639172/viewspace-539841/，如需轉載，請註明出處，否則將追究法律責任。

c#-跨執行緒控制元件訪問問題

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