c# - 秒表的数据绑定(bind)问题已过去

Question

我正在尝试创建一个类，当它启动时它会启动一个秒表，并且一直将耗时写入一个局部变量 Elapsed，我有一个数据绑定(bind)到的 Listview。但是当我使用这段代码时，Listview 只显示 00:00:00.00000001 并且永远不会改变。该类的代码是:

namespace project23{    public class ActiveEmployee    {        public int EmpID { get; set; }        public string EmpName { get; set; }        private DateTime date;        private BackgroundWorker worker;        public Stopwatch sw;        public ActiveEmployee(int empID, string empName)        {            date = DateTime.Now;            worker = new BackgroundWorker();            worker.DoWork += BackgroundWork;            worker.WorkerReportsProgress = true;            worker.RunWorkerAsync();        }        private TimeSpan elapsed;        public TimeSpan Elapsed        {            get { return elapsed; }            set            {                elapsed = value;                NotifyPropertyChanged("Elapsed");            }        }        private void BackgroundWork(object sender, DoWorkEventArgs args)        {            sw = new Stopwatch();            sw.Start();            if(true)            {                Elapsed = sw.Elapsed;            }        }        public event PropertyChangedEventHandler PropertyChanged;        private void NotifyPropertyChanged(String info)        {            if (PropertyChanged != null)            {                PropertyChanged(this, new PropertyChangedEventArgs(info));            }        }    }}

现在它可以使用定时器代替

using System;using System.ComponentModel;using System.Timers;
namespace Eksamen_Januar_2011{    public class ActiveEmployee : INotifyPropertyChanged    {        public int EmpID { get; set; }        public string EmpName { get; set; }        private DateTime startDate;        private BackgroundWorker worker;        private Timer timer;
    public ActiveEmployee(int empID, string empName)
    {
        startDate = DateTime.Now;
        worker = new BackgroundWorker();
        worker.DoWork += BackgroundWork;
        timer = new Timer(1000);
        timer.Elapsed += TimerElapsed;
        worker.RunWorkerAsync();
    }

    private TimeSpan elapsed;
    public TimeSpan Elapsed
    {
        get { return elapsed; }
        set
        {
            elapsed = value;
            NotifyPropertyChanged("Elapsed");
        }
    }

    private void BackgroundWork(object sender, DoWorkEventArgs args)
    {
        timer.Start();
    }
    private void TimerElapsed(object sender, ElapsedEventArgs e)
    {
        Elapsed = DateTime.Now - startDate;
    }
    public event PropertyChangedEventHandler PropertyChanged;

    private void NotifyPropertyChanged(String info)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(info));
        }
    }
}

Answer 1

您需要实现 INotifyPropertyChanged 接口(interface)。将您的类声明修改为:

public class Employee : System.ComponentModel.INotifyPropertyChanged

参见 http://msdn.microsoft.com/en-us/library/system.componentmodel.inotifypropertychanged.aspx .