Thread交叉访问的问题.....

本来在做下载的进度条,自己的线程访问 ProgressBar时候出现错误:

错误代码
     private void down_Click(object sender, EventArgs e)
        {
            Thread th = new Thread(new ThreadStart(downfile));
            th.Start();

         
        }
       
        private void downfile()
        {
                   //--..这里错误ThreadStateExceptionwasunhandled- -我靠怎么这样啊
                   
                    ProgressDownBar.Value= ProgressDownBar.Maximum;
  }
}

- -上网搜索下,原来我自己创建的线程和ui的线程不在一起.....看的我头大.

具体资料请看http://www.yoda.arachsys.com/csharp/threads/winforms.shtml

一直接调用委托不行的必须是,MethodInvoker updateCounterDelegate = new MethodInvoker(UpdateCount);

这个委托才可以,但是好象不能传递参数,可以通过,下面的方式传递参数,而且这样写就可以访问ui线程

 

        int  currentCount;

         void  UpdateCount()
         {
            int tmpCount;
            lock (stateLock)
            {
                tmpCount = currentCount;
            }
            counter.Text = tmpCount.ToString();
        }

 

二.- -另外自定义委托的调用

delegate void StringParameterDelegate(string value);

 

 

// -----用线程直接访这个方法就可以  
void  UpdateStatus( string  value)
         {//--判断是否在ui线程中工作哦　
            if (InvokeRequired)
            {

                //--BeginInvoke 所调用的委托根本就是在 UI 线程中执行的。- -优点想递调用
                // We're not in the UI thread, so we need to call BeginInvoke
                BeginInvoke(new StringParameterDelegate(UpdateStatus), new object[] { value });
                return;
            }
            // Must be on the UI thread if we've got this far，如果在直接设置
            statusIndicator.Text = value;
        }

 

 

例子

 

 

 

 

 

 

 

test_2.Designer.cs
namespace DowonFile
{
    partial class test_2
    {
        /**//// 

        /// Required designer variable.
        /// 

        private System.ComponentModel.IContainer components = null;

        /**//// 

        /// Clean up any resources being used.
        /// 

        /// true if managed resources should be disposed; otherwise, false.
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        Windows Form Designer generated code#region Windows Form Designer generated code

        /**//// 

        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// 

        private void InitializeComponent()
        {
            this.button1 = new System.Windows.Forms.Button();
            this.progressBar1 = new System.Windows.Forms.ProgressBar();
            this.progressBar2 = new System.Windows.Forms.ProgressBar();
            this.SuspendLayout();
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(205, 46);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(75, 23);
            this.button1.TabIndex = 0;
            this.button1.Text = "button1";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // progressBar1
            // 
            this.progressBar1.Location = new System.Drawing.Point(-3, 107);
            this.progressBar1.Name = "progressBar1";
            this.progressBar1.Size = new System.Drawing.Size(202, 23);
            this.progressBar1.TabIndex = 1;
            // 
            // progressBar2
            // 
            this.progressBar2.Location = new System.Drawing.Point(-3, 46);
            this.progressBar2.Name = "progressBar2";
            this.progressBar2.Size = new System.Drawing.Size(202, 23);
            this.progressBar2.TabIndex = 2;
            // 
            // test_2
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(292, 273);
            this.Controls.Add(this.progressBar2);
            this.Controls.Add(this.progressBar1);
            this.Controls.Add(this.button1);
            this.Name = "test_2";
            this.Text = "test_2";
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.ProgressBar progressBar1;
        private System.Windows.Forms.ProgressBar progressBar2;
    }
}

 

test_2.cs
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Net;
using System.IO;
using System.Threading;



namespace DowonFile
{
    public partial class test_2 : Form
    {
        /**//// 

        /// 线程用到的委托
        /// 

        /// 
        delegate void StringParameterDelegate(int v);

        public test_2()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {

          Thread t1 = new Thread(new ThreadStart(ThreadJob));
            //--设置为后台主线程
            t1.IsBackground = true;
            t1.Start();



            Thread t2 = new Thread(new ThreadStart(T2));
            //--设置为后台主线程
            t2.IsBackground = true;
            t2.Start();
        }

        void ThreadJob()
        {

            for (int i = 0; i < 100; i++)
            {
                UpdateStatus(i);

                Thread.Sleep(100);
            }

        }


        void UpdateStatus(int v)
        {//--判断是否在ui线程中工作哦　
            if (InvokeRequired)
            {

                //--BeginInvoke 所调用的委托根本就是在 UI 线程中执行的。
                // We're not in the UI thread, so we need to call BeginInvoke
                BeginInvoke(new StringParameterDelegate(UpdateStatus), new object[] { v });
                return;
            }
            // Must be on the UI thread if we've got this far，如果在直接设置
            progressBar1.Value = v;
        }



        void T2()
        {
            for (int i = 0; i < 100; i++)
            {
                U2(i);

                Thread.Sleep(600);
            }
        
        }
        void U2(int v)
        {
            //--判断是否在ui线程中工作哦　
            if (InvokeRequired)
            {

                //--BeginInvoke 所调用的委托根本就是在 UI 线程中执行的。
                // We're not in the UI thread, so we need to call BeginInvoke
                BeginInvoke(new StringParameterDelegate(U2), new object[] { v });
                return;
            }
            // Must be on the UI thread if we've got this far，如果在直接设置
            progressBar2.Value = v;
        }

    }
}

 

 

转载于:https://www.cnblogs.com/ajaxren/archive/2008/07/24/1250629.html