C# 根据BackgroundWorker异步模型和ProgressBar控件,自定义进度条控件

前言

程序开发过程中,难免会有的业务逻辑,或者算法之类产生让人能够感知的耗时操作,例如循环中对复杂逻辑处理;获取数据库百万乃至千万级数据;http请求的时候等......
用户在使用UI操作并不知道程序的内部处理,从而误操作导致程序无响应,关闭程序等待影响体验的情况,因此,在等待过程中提供友好的等待提示是有必要的,接下来
我们一起封装一个自定义进度条控件!

主要使用技术(C#相关)

• BackgroundWoker异步模型
• ProgressBar控件
• 泛型
• 定时器 System.Timers.Timer

自定义控件开发

项目解决方案

• BackgroundworkerEx : 自定义进度条控件工程
• Test : 调用BackgroundworkerEx的工程(只是展示如何调用)

处理控件样式

• 新建一个ProgressbarEx名称的 用户控件

• 添加Labal控件(lblTips),用于展示进度条显示的信息状态

• 添加一个PictureBox控件(PicStop),充当关闭按钮,用于获取用户点击事件,触发关闭/终止进度条

• 添加进度条ProgressBar控件(MainProgressBar)

• 处理代码如下:

1. 进度条样式为"不断循环",并且速度为50
2. 该自定义用户控件不展示在任务栏中
3. 图片控件被点击事件------>设置当前属性IsStop=true,指示过程终止;
4. TipMessage属性,用于设置进度条的信息
5. SetProgressValue(int value) 设置进度条的Value属性,使得在ProgressBarStyle.Marquee样式中动画平滑
6. MouseDown/MouseUp/MouseMove这三个事件是用于拖动无边框的用户控件(代码就不贴了)

public ProgressbarEx()
{
    InitializeComponent();

    MainProgressBar.Style = ProgressBarStyle.Marquee;
    MainProgressBar.MarqueeAnimationSpeed = 50;

    this.ShowInTaskbar = false;

    PicStop.Click += (s, eve) =>
    {
    IsStop = true;
    };

    this.MouseDown += CusProgressForm_MouseDown;
    this.MouseUp += CusProgressForm_MouseUp;
    this.MouseMove += CusProgressForm_MouseMove;
}

/// <summary>
/// Need Stop ?
/// </summary>
public bool IsStop { get; private set; } = false;

/// <summary>
/// TipMessage
/// </summary>
public string TipMessage { get; set; }

/// <summary>
/// TipMessage
/// </summary>
public string TipMessage
{
    get
    {
    return lblTips.Text;
    }
    set
    {

    lblTips.Text = value;
    }
}

/// <summary>
/// Set ProgressBar value ,which makes ProgressBar smooth
/// </summary>
/// <param name="value"></param>
public void SetProgressValue(int value)
{
    if (MainProgressBar.Value == 100) MainProgressBar.Value = 0;

    MainProgressBar.Value += value;

}

到现在,这个自定义进度条控件的样式基本完成了.

功能逻辑处理

运行前所需

• 定义BackgroundWorkerEx<T>泛型类,并且继承于 IDisposable
  1. 释放资源;

 		/// <summary>
        /// Dispose
        /// </summary>
        public void Dispose()
        {
            try
            {
                DoWork = null;
                RunWorkCompleted = null;
                WorkStoped = null;

                _mWorkerThread = null;
                _mWorker.Dispose();
                _mWorker = null;
                _mTimer = null;
            }
            catch (Exception){}
        }

2. T用与异步处理的时候,传递T类型

• 因为我们是通过.Net 的 BackgroundWorker异步模型来做的,所以我们理所当然定义相关的事件:
  1. 异步开始
  2. 异步完成
  3. 加上我们自定义扩展的异步停止
  4. ......报告进度事件在此进度条样式中并不需要

我们先定义这四个事件所用到的参数,因为在BackgroundWorkerEx<T>泛型类中,我们还是使用BackgroundWorker来处理异步过程,因此我们定义的参数泛型类需要继承原来的参数类型,并且在传输传递中,将原生BackgroundWorker的Argument,Result属性转成全局的泛型T,这样我们在外部调用的时候,拿到的返回结果就是我们传入到BackgroundWorkerEx<T>泛型类中的T类型,而不需要使用as进行转换; 注:因为原生没有停止相关事件,所以自定义异步停止的事件参数使用的是DoWorkEventArgs<T>

    public class DoWorkEventArgs<T> : DoWorkEventArgs
    {
        public new T Argument { get; set; }
        public new T Result { get; set; }
        public DoWorkEventArgs(object argument) : base(argument)
        {
            Argument = (T)argument;
        }
    }


    public class RunWorkerCompletedEventArgs<T> : RunWorkerCompletedEventArgs
    {
        public new T Result { get; set; }
        public RunWorkerCompletedEventArgs(object result, Exception error, bool cancelled) : base(result, error, cancelled)
        {
            Result = (T)result;
        }
    }

接着我们需要去定义事件,参数使用以上定义的泛型类

	public delegate void DoWorkEventHandler(DoWorkEventArgs<T> Argument);
        /// <summary>
        /// StartAsync
        /// </summary>
        public event DoWorkEventHandler DoWork;

        public delegate void StopEventHandler(DoWorkEventArgs<T> Argument);
        /// <summary>
        /// StopAsync
        /// </summary>
        public event StopEventHandler WorkStoped;

        public delegate void RunWorkCompletedEventHandler(RunWorkerCompletedEventArgs<T> Argument);
        /// <summary>
        /// FinishAsync
        /// </summary>
        public event RunWorkCompletedEventHandler RunWorkCompleted;

• 定义全局的字段
  1. private BackgroundWorker _mWorker = null;异步操作必要;
  2. private T _mWorkArg = default(T);操作传递进来的参数类并且返回到外部
  3. private Timer _mTimer; 定时器检测自定义进度条控件属性IsStop是否为true,并且动态修改进度条消息
  4. private Thread _mWorkerThread = null;异步操作在该线程中,终止时调用About()抛出ThreadAbortException异常,用于标记当前是停止而不是完成状态
  5. private int _miWorkerStartDateSecond = 0; 异步消耗时间(非必要)
  6. private int _miShowProgressCount = 0; 动态显示"."的个数(非必要)
  7. private ProgressbarEx _mfrmProgressForm = null; 自定义进度条控件实例

        /// <summary>
        /// .Net  BackgroundWorker
        /// </summary>
        private BackgroundWorker _mWorker = null;

        /// <summary>
        /// Whole Para
        /// </summary>
        private T _mWorkArg = default(T);

        /// <summary>
        /// Timer
        /// </summary>
        private Timer _mTimer = null;

        /// <summary>
        /// WorkingThread
        /// </summary>
        private Thread _mWorkerThread = null;

        /// <summary>
        /// Async time sec
        /// </summary>
        private int _miWorkerStartDateSecond = 0;

        /// <summary>
        /// Async time dot
        /// </summary>
        private int _miShowProgressCount = 0;

        /// <summary>
        /// ProgressbarEx
        /// </summary
        private ProgressbarEx _mfrmProgressForm = null;

• 定义全局属性

1. IsBusy 返回_mWorker的工作忙碌是否
2. ProgressTip 自定义进度条控件显示内容

	/// <summary>
        /// Express Busy
        /// </summary>
        public bool IsBusy
        {
            get
            {
                if (_mWorker != null)
                {
                    return _mWorker.IsBusy;
                }
                return false;
            }
        }

        /// <summary>
        /// 进度条提示 默认： 正在加载数据，请稍后[{0}]{1}
        /// </summary>
        public string ProgressTip { get; set; } = "Elapsed Time[{0}]{1}";

**到现在,我们已经将必要的字段,属性,样式都处理完成!!! ** 接下来我们就要实现方法

方法实现

• 异步工作事件,用法与BackgroundWorker一致,

  1. 如果调用处没有注册DoWork事件,则直接返回

  2. 将接受到的参数创建成泛型参数类

  3. 开线程,将异步操作放在该线程中操作,注意设置线程的IsBackground=true,防止主进程意外退出,线程还在处理

  4. 循环直到线程结束

  5. e.Result = Argument.Result;将结果赋予Result,在停止或者完成事件中可以获取到结果

		/// <summary>
        /// Working
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Worker_DoWork(object sender, DoWorkEventArgs e)
        {
            if (DoWork == null)
            {
                e.Cancel = true;
                return;
            }

            DoWorkEventArgs<T> Argument = new DoWorkEventArgs<T>(e.Argument);

            try
            {
                if (_mWorkerThread != null && _mWorkerThread.IsAlive)
                {
                    _mWorkerThread.Abort();
                }
            }
            catch (Exception)
            {
                Thread.Sleep(50);
            }

            _mWorkerThread = new Thread(a =>
            {
                try
                {
                    DoWork?.Invoke(a as DoWorkEventArgs<T>);
                }
                catch (Exception)
                {

                }
            });

            _mWorkerThread.IsBackground = true;
            _mWorkerThread.Start(Argument);

            //Maybe cpu do not start thread
            Thread.Sleep(20);

            //Wait.....
            while (_mWorkerThread.IsAlive)
            {
                Thread.Sleep(50);
            }
            e.Result = Argument.Result;
        }

• 异步完成/停止

  当线程停止抛出异常(catch但是不处理)/线程完成时会进入异步完成事件

  1. 完成后,将自定义进度条控件实例关闭,释放

2. 将全局的BackgroundWorker实例_mWorker相关事件取消注册,并且检查线程情况
3. 感觉线程情况,如果线程状态为ThreadState.Aborted意味着线程被停止了,调用停止事件,否则调用完成事件

	  /// <summary>
      /// Completed
      /// </summary>
      /// <param name="sender"></param>
      /// <param name="e"></param>
      private void Worker_RunWorkCompleted(object sender, RunWorkerCompletedEventArgs e)
      {
          try
          {
              if (_mfrmProgressForm != null)
              {
                _mfrmProgressForm.Close();
                  _mfrmProgressForm.Dispose();
                _mfrmProgressForm = null;
              }

                if (_mWorker != null)
                {
                    _mWorker.DoWork -= Worker_DoWork;
                    _mWorker.RunWorkerCompleted -= Worker_RunWorkCompleted;

                    try
                    {
                        if (_mWorkerThread != null && _mWorkerThread.IsAlive) _mWorkerThread.Abort();
                    }
                    catch (Exception) { }
                }

              //In timer, When stop progress will make thread throw AbortException
              if (_mWorkerThread != null && _mWorkerThread.ThreadState == ThreadState.Aborted)
            {
                  WorkStoped?.Invoke(new DoWorkEventArgs<T>(_mWorkArg));
              }
              else
              {
                  RunWorkCompleted?.Invoke(new RunWorkerCompletedEventArgs<T>(e.Result, e.Error, e.Cancelled));
              }
          }
          catch (Exception ex)
          {
              throw ex;
          }
      }

• 线程开始

  1. 检查消息提醒内容 , {0}{1}同于显示异步耗时和".."的个数
  2. 在定时器执行方法中,检查_mfrmProgressForm.IsStop是否为true,这个属性标志是否被停止;true则抛出异常
  3. _mfrmProgressForm不为Null则不断修改当前的内容提醒,友好化,实际可以按需处理

  		  /// <summary>
          /// Timer Start 
          /// </summary>
          private void StartTimer()
          {
              //Check user ProgressTip
              if (!ProgressTip.Contains("{0}"))
              {
                  ProgressTip += "...Elapsed Time{0}{1}";
              }
  
              if (_mTimer != null) return;
  
              //On one sec 
              _mTimer = new Timer(1000);
              _mTimer.Elapsed += (s, e) =>
              {
                  //progress and it's stop flag (picture stop)||  this stop flag
                  if (_mfrmProgressForm != null && _mfrmProgressForm.IsStop)
                  {
                      if (_mWorker != null)
                      {
                          try
                          {
                              if (_mWorkerThread != null && _mWorkerThread.IsAlive)
                              {
                                  if (_mTimer != null && _mTimer.Enabled)
                                  {
                                      _mTimer.Stop();
                                      _mTimer = null;
                                  }
                                  _mWorkerThread.Abort();
                              }
                          }
                          catch (Exception) { }
                      }
                  }
  
                  if (_mfrmProgressForm != null)
                  {
                      //Callback 
                      _mfrmProgressForm.Invoke(new Action<DateTime>(elapsedtime =>
                      {
                          DateTime sTime = elapsedtime;
  
                          //worked time
                          _miWorkerStartDateSecond++;
                          if (_mfrmProgressForm != null)
                          {
                              _mfrmProgressForm.SetProgressValue(_miWorkerStartDateSecond);
                          }
  
                          //.....count
                          _miShowProgressCount++;
  
                          if (_miShowProgressCount > 6)
                          {
                              _miShowProgressCount = 1;
                          }
  
                          string[] strs = new string[_miShowProgressCount];
  
                          string ProgressStr = string.Join(".", strs);
  
                          string ProgressText = string.Format(ProgressTip, _miWorkerStartDateSecond, ProgressStr);
  
                          if (_mfrmProgressForm != null)
                          {
                              _mfrmProgressForm.TipMessage = ProgressText;
                          }
                      }), e.SignalTime);
                  }
              };
  
              if (!_mTimer.Enabled)
              {
                  _mTimer.Start();
              }
          }
  

• 最后一步:异步开始 与BackgroundWorker用法一致,只是在最后开始了定时器和进度条控件而已

  /// <summary>
          /// Start AsyncWorl
          /// </summary>
          /// <param name="Para"></param>
          public void AsyncStart(T Para)
          {
              //if workeven is  null ,express user do not regist event
              if (DoWork == null)
              {
                  return;
              }
  
              _miWorkerStartDateSecond = 0;
              _miShowProgressCount = 0;
  
              //init
              if (_mWorker != null && _mWorker.IsBusy)
              {
                  _mWorker.CancelAsync();
                  _mWorker = null;
              }
  
              _mWorker = new BackgroundWorker();
  
              //create progressbar
              _mfrmProgressForm = new ProgressbarEx();
  
              //add event
              _mWorker.DoWork += Worker_DoWork;
              _mWorker.RunWorkerCompleted += Worker_RunWorkCompleted;
  
              _mWorker.WorkerReportsProgress = true;
              _mWorker.WorkerSupportsCancellation = true;
  
              //Set Whole Para
              _mWorkArg = Para;
  
              _mWorker.RunWorkerAsync(Para);
              //Start timer
              StartTimer();
  
              _mfrmProgressForm.StartPosition = FormStartPosition.CenterParent;
              _mfrmProgressForm.ShowDialog();
          }
  

到这里,整个的进度条控件已经完成了!

调用

• 定义一个参数类

	/// <summary>
    /// Para Class
    /// </summary>
    public class ParaArg
    {
        public DataTable Data { get; set; }
        public string Msg { get; set; }
        public Exception Ex { get; set; }
    }

• 定义全局的帮助类BackgroundWorkerEx<ParaArg> workHelper = null;
• 调用

				if (workHelper != null || (workHelper != null && workHelper.IsBusy))
                {
                    workHelper.Dispose();
                    workHelper = null;
                }
                if (workHelper == null)
                {
                    workHelper = new BackgroundWorkerEx<ParaArg>();
                }

                workHelper.DoWork += (eve) =>
                {
                    ParaArg args = eve.Argument;

                    try
                    { 
                        //ToDo  like Thread.Sleep(20000);
                        Thread.Sleep(10000);
                        args.Msg = "...this is bussiness code result";
                        throw new Exception("");
                    }
                    catch (Exception ex)
                    {
                        args.Ex = ex;
                    }
                    finally
                    {
                        eve.Result = args;
                    }

                };
                workHelper.RunWorkCompleted += (eve) =>
                {
                    if (eve.Error != null)
                    {
                        //get .net backgroundworker exception;
                        //handle this exception;
                        //return ?
                    }

                    //get your para result
                    ParaArg x = eve.Result;
                 
                    if (x.Ex != null)
                    {
                        //get your bussiness exception;
                        //handle this exception;
                        //return ?
                    }

                    //finially get your need;
                    //MayBe to do some UI hanlde and bussiness logical
                    string sReusltMsg = x.Msg;
                };

                workHelper.WorkStoped += (eve) =>
                { 
                    //if stoped ! it means no error;
                    //just get what you want; 
                    ParaArg x = eve.Result as ParaArg;

                    btnBegin.Enabled = true;
                };

                //参数
                ParaArg arg = new ParaArg()
                {
                    Msg = "Msg"
                };

                workHelper.AsyncStart(arg);

最后

其实不管是封装的过程,还是调用,可以说完全就是BackgroundWorker的方式,所以很多BackgroundWorker相关的地方我都没有很详细的去说明;只要看看这个异步模型,就能够很好理解!大家有空也可以实现以下,有问题也可以详细,我比较喜欢交流技术~~~

还有一点就是这个解决方案已经放上Github上了,欢迎大家拉下来用

• GitHub地址 欢迎star/fork