一个关于多线程的问题

Question

我要在WinForm里实现这样一个功能：点击一个按钮，程序创建一个新后台线程，处理一个需要一定时间的任务（比如：发电子邮件或者复制文件等），此时，主窗体不能没有响应。处理完后，返回操作结果，主窗体显示处理结果。在处理时，主窗体能显示处理进度更好。
最好能提供示例代码。本人菜鸟，望赐教。

Answer 1

本帖最后由 bdmh 于 2012-08-01 16:23:00 编辑

  

Answer 2

private void button1_Click(object sender, EventArgs e)
        {
            new Thread(() =>
            {
                for(int i=0;i<10000;i++)
                {
                    Invoke((MethodInvoker)(() => { progressBar1.Value = i; }));
                }
            }).Start();
        }

Answer 3

拷贝文件的例子
类代码:
using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Threading;namespace WindowsFormsApplication1
{
    /// <summary>
    /// 继续滥用委托
    /// </summary>
    /// <param name="sourceFile"></param>
    /// <param name="targetFile"></param>
    public delegate void CopyProgressHandler(String sourceFile, String targetFile);    /// <summary>
    /// 拷贝文件夹类
    /// </summary>
    public class CopyDirectory
    {
        /// <summary>
        /// 继续滥用事件
        /// </summary>
        public event CopyProgressHandler CopyProgress;        #region Win32 API        private const int MAX_PATH = 260;
        private const int MAX_ALTERNATE = 14;        [StructLayout(LayoutKind.Sequential)]
        private struct FILETIME
        {
            public uint dwLowDateTime;
            public uint dwHighDateTime;
        };        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        private struct WIN32_FIND_DATA
        {
            public FileAttributes dwFileAttributes;
            public FILETIME ftCreationTime;
            public FILETIME ftLastAccessTime;
            public FILETIME ftLastWriteTime;
            public uint nFileSizeHigh; //changed all to uint from int, otherwise you run into unexpected overflow
            public uint nFileSizeLow;  //| http://www.pinvoke.net/default.aspx/Structures/WIN32_FIND_DATA.html
            public uint dwReserved0;   //|
            public uint dwReserved1;   //v
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_PATH)]
            public string cFileName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_ALTERNATE)]
            public string cAlternate;
        }        [DllImport("kernel32", CharSet = CharSet.Unicode)]
        private static extern IntPtr FindFirstFile(string lpFileName, out WIN32_FIND_DATA lpFindFileData);        [DllImport("kernel32", CharSet = CharSet.Unicode)]
        private static extern bool FindNextFile(IntPtr hFindFile, out WIN32_FIND_DATA lpFindFileData);        [DllImport("kernel32.dll", SetLastError = true)]
        private static extern bool FindClose(IntPtr hFindFile);        #endregion        /// <summary>
        /// 拷贝
        /// </summary>
        /// <param name="sourceDirectory">源文件</param>
        /// <param name="targetDirectory">目标文件夹</param>
        public void Copy(String sourceDirectory, String targetDirectory)
        {
            IntPtr INVALID_HANDLE_VALUE = new IntPtr(-1);
            WIN32_FIND_DATA findData;            IntPtr findHandle;            findHandle = FindFirstFile(sourceDirectory + "*.*", out findData);
            if (findHandle != INVALID_HANDLE_VALUE)
            {
                do
                {
                    if ((findData.dwFileAttributes & FileAttributes.Directory) != 0)
                    {
                        if (findData.cFileName != "." && findData.cFileName != "..")
                        {
                            Copy(String.Format("{0}{1}{2}", sourceDirectory, findData.cFileName, "\\"), targetDirectory);
                        }
                    }
                    else
                    {
                        String strFile = sourceDirectory + findData.cFileName;
                        if (File.Exists(strFile))
                        {
                            try
                            {
                                FileInfo fileInfo = new FileInfo(strFile);
                                String strCopyTargetFile = String.Format("{0}{1}", targetDirectory, fileInfo.Name);
                                if (CopyProgress != null)
                                {
                                    // 触发事件,通知界面
                                    CopyProgress(strFile, strCopyTargetFile);
                                }
                                // 拷贝文件
                                File.Copy(strFile, strCopyTargetFile);
                            }
                            catch
                            {
                            }
                        }
                    }
                }
                while (FindNextFile(findHandle, out findData));
                FindClose(findHandle);
            }
        }
    }
}
窗体代码:using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Threading;namespace WindowsFormsApplication1
{
    /// <summary>
    /// 继续滥用委托
    /// </summary>
    /// <param name="sourceFile"></param>
    /// <param name="targetFile"></param>
    public delegate void CopyProgressHandler(String sourceFile, String targetFile);    /// <summary>
    /// 拷贝文件夹类
    /// </summary>
    public class CopyDirectory
    {
        /// <summary>
        /// 继续滥用事件
        /// </summary>
        public event CopyProgressHandler CopyProgress;        #region Win32 API        private const int MAX_PATH = 260;
        private const int MAX_ALTERNATE = 14;        [StructLayout(LayoutKind.Sequential)]
        private struct FILETIME
        {
            public uint dwLowDateTime;
            public uint dwHighDateTime;
        };        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        private struct WIN32_FIND_DATA
        {
            public FileAttributes dwFileAttributes;
            public FILETIME ftCreationTime;
            public FILETIME ftLastAccessTime;
            public FILETIME ftLastWriteTime;
            public uint nFileSizeHigh; //changed all to uint from int, otherwise you run into unexpected overflow
            public uint nFileSizeLow;  //| http://www.pinvoke.net/default.aspx/Structures/WIN32_FIND_DATA.html
            public uint dwReserved0;   //|
            public uint dwReserved1;   //v
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_PATH)]
            public string cFileName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_ALTERNATE)]
            public string cAlternate;
        }        [DllImport("kernel32", CharSet = CharSet.Unicode)]
        private static extern IntPtr FindFirstFile(string lpFileName, out WIN32_FIND_DATA lpFindFileData);        [DllImport("kernel32", CharSet = CharSet.Unicode)]
        private static extern bool FindNextFile(IntPtr hFindFile, out WIN32_FIND_DATA lpFindFileData);        [DllImport("kernel32.dll", SetLastError = true)]
        private static extern bool FindClose(IntPtr hFindFile);        #endregion        /// <summary>
        /// 拷贝
        /// </summary>
        /// <param name="sourceDirectory">源文件</param>
        /// <param name="targetDirectory">目标文件夹</param>
        public void Copy(String sourceDirectory, String targetDirectory)
        {
            IntPtr INVALID_HANDLE_VALUE = new IntPtr(-1);
            WIN32_FIND_DATA findData;            IntPtr findHandle;            findHandle = FindFirstFile(sourceDirectory + "*.*", out findData);
            if (findHandle != INVALID_HANDLE_VALUE)
            {
                do
                {
                    if ((findData.dwFileAttributes & FileAttributes.Directory) != 0)
                    {
                        if (findData.cFileName != "." && findData.cFileName != "..")
                        {
                            Copy(String.Format("{0}{1}{2}", sourceDirectory, findData.cFileName, "\\"), targetDirectory);
                        }
                    }
                    else
                    {
                        String strFile = sourceDirectory + findData.cFileName;
                        if (File.Exists(strFile))
                        {
                            try
                            {
                                FileInfo fileInfo = new FileInfo(strFile);
                                String strCopyTargetFile = String.Format("{0}{1}", targetDirectory, fileInfo.Name);
                                if (CopyProgress != null)
                                {
                                    // 触发事件,通知界面
                                    CopyProgress(strFile, strCopyTargetFile);
                                }
                                // 拷贝文件
                                File.Copy(strFile, strCopyTargetFile);
                            }
                            catch
                            {
                            }
                        }
                    }
                }
                while (FindNextFile(findHandle, out findData));
                FindClose(findHandle);
            }
        }
    }
}

Answer 4

不要这样喂
不要这样喂
Directory.GetFiles太垃圾了
竟然不是异步的
文件一多
就有可能卡死界面
有木有?
有木有?

Answer 5

可能上面的问题表述不够清楚,我再重新说下
        private void SendEmail()
        {
            try
            {
                client.Send(msg);
                tSSlblStatus.Text = "发送完成";
                MessageBox.Show("发送成功", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            catch (Exception ex)
            {
                tSSlblStatus.Text = "发送失败";
                MessageBox.Show(ex.Message, "发送邮件出错", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
            }
            tSSlblStatus.Text = "";
            txtReceive.Enabled = true; //这几句设置Enable的语句会出错
            txtTitle.Enabled = true;
            txtNeirong.Enabled = true;
            btSend.Enabled = true;
            btSettings.Enabled = true;
            cByxj.Enabled = true;
        }        private void btSend_Click(object sender, EventArgs e)
        {
            tSSlblStatus.Text = "准备发送...";
            txtReceive.Enabled = false;
            txtTitle.Enabled = false;
            txtNeirong.Enabled = false;
            btSend.Enabled = false;
            btSettings.Enabled = false;
            cByxj.Enabled = false;
...
            Thread thread = new Thread(new ThreadStart(SendEmail));
            tSSlblStatus.Text = "正在发送邮件...";
            thread.Start();
        }这是我编的发送电子邮件的例子。线程结束前，需要将发送成功，或者失败的信息传送给主窗体，将MessageBox显示和改变控件Text、Enable的代码移到主窗体中，最好能将这些代码放进一个新的方法中，当主窗体收到线程的消息时执行这个方法。

Answer 6

        public Form1()
        {
            InitializeComponent();
            Control.CheckForIllegalCrossThreadCalls = false;
        }加上CheckForIllegalCrossThreadCalls = false就行了

Answer 7

1:利用lambda表达式做闭包
2：在上面闭包的基础上传递一个委托进去 线程返回时回调 或者用Task什么的来做 这个支持异步回调的

Answer 8

using System;
using System.Threading;namespace Test
{
    class Program
    {        private static void Foo(Object obj)
        {
            if(obj != null)
            {
                ThreadData threadData = obj as ThreadData;
                if (threadData != null)
                {
                        Console.WriteLine(String.Format("ThreadName={0},RunTime={1}", threadData.ThreadName, threadData.RunTime));
                }
            }
        }        static void Main()
        {
            ThreadData threadData = new ThreadData();
            threadData.ThreadName = "TestThread";
            threadData.RunTime = System.DateTime.Now;            Thread t = new Thread(new ParameterizedThreadStart(Foo));
            t.IsBackground = true;
            t.Start(threadData);            Console.ReadKey();
        }
    }    class ThreadData
    {
        public String ThreadName;
        public DateTime RunTime;
    }
}

Answer 9

我不想用Control.CheckForIllegalCrossThreadCalls = false;的方法
不想在子线程中控制主窗体的控件。
MessageBox.Show("发送成功", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
MessageBox.Show(ex.Message, "发送邮件出错", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
tSSlblStatus.Text = "";
txtReceive.Enabled = true;
txtTitle.Enabled = true;
txtNeirong.Enabled = true;
btSend.Enabled = true;
btSettings.Enabled = true;
cByxj.Enabled = true;我希望把这些语句放到主窗体中。
因此必须在子线程运行完成后传送一个参数给主窗体，由主窗体执行这些语句。
怎样才能实现？

Answer 10

程序现在改成这样，没有问题了，传递参数和回调已经实现。就是传回参数时，用的是全局变量，闭包还是没搞懂。
        public class ResultShow
        {
            public bool Success;
            public string ErrMessage;
            public ResultShow()
            {
                Success = false;
                ErrMessage = "";
            }
            public ResultShow(bool suc)
            {
                Success = suc;
                if (suc)
                    ErrMessage = "";
                else
                    ErrMessage = "Unknown Error";
            }
            public ResultShow(bool suc, string errm)
            {
                Success = suc;
                if (suc)
                    ErrMessage = "";
                else
                    ErrMessage = errm;
            }
        }        public static ResultShow r1 = new ResultShow();
        public delegate void MyInvoke();        private void SendEmail(object msg)
        {
            try
            {
                client.Send((MailMessage)msg);
                r1.Success = true;
            }
            catch (Exception ex)
            {
                r1.Success = false;
                r1.ErrMessage = ex.Message;
            }
            MyInvoke mi = new MyInvoke(SendEnd);
            this.BeginInvoke(mi);
        }        private void SendEnd()
        {
            if (r1.Success)
            {
                tSSlblStatus.Text = "发送完成";
                MessageBox.Show("发送成功", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            else
            {
                tSSlblStatus.Text = "发送失败";
                MessageBox.Show(r1.ErrMessage, "发送邮件出错", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
            }
            tSSlblStatus.Text = "";
            txtReceive.Enabled = true;
            txtTitle.Enabled = true;
            txtNeirong.Enabled = true;
            btSend.Enabled = true;
            btSettings.Enabled = true;
            cByxj.Enabled = true;
        }        private void btSend_Click(object sender, EventArgs e)
        {
            tSSlblStatus.Text = "准备发送...";
            txtReceive.Enabled = false;
            txtTitle.Enabled = false;
            txtNeirong.Enabled = false;
            btSend.Enabled = false;
            btSettings.Enabled = false;
            cByxj.Enabled = false;
            string mailContent = txtNeirong.Text;            MailMessage msg = new System.Net.Mail.MailMessage();
...
            Thread thread = new Thread(new ParameterizedThreadStart(SendEmail));
            thread.IsBackground = true;
            tSSlblStatus.Text = "正在发送邮件...";
            thread.Start(msg);
        }