表示在 Thread 上执行的方法的委托方法，ThreadStart不能带参数，ParameterizedThreadStart是2.0中新增的，可以带参数（object类型的）

using System.Threading;

public void ShowMsg()
{
    MessageBox.Show("Message Info.");
}

Thread thread = new Thread(new ThreadStart(ShowMsg));
thread.Start();

//带参数

public void ShowMsg(object msg)
{
    MessageBox.Show(msg.ToString());
}

Thread threadWithParam = new Thread(new ParameterizedThreadStart(new ThreadTest().ShowMsg));
threadWithParam.Start("this is a param.");