C#中线程调用带有参数的方法

c#为我们提供thread可以这么用：

Thread t = new Thread(new ThreadStart(ScreenMonitor));
t.Start();

public void ScreenMonitor()
{         
　//操作
 }

如果想在方法中传入参数怎么办？并且还不止一个参数！

        struct ImageParam
        {
            public int a;
            public int b;
            public int c;
            public int d;
        }

        public void ScreenMonitor(Object args)
        {
            para = (ImageParam)args;
            int aa = para.a;
            int bb = para.b;
            int cc = para.c;
            int dd = para.d;
            Bitmap myImage = new Bitmap(aa, bb);
            Graphics g = Graphics.FromImage(myImage);
            g.CopyFromScreen(new Point(cc, dd), new Point(0, 0), new Size(aa, bb));
            String picpath = @"d:\test.jpg";
            myImage.Save(picpath);
            g.Dispose();
            myImage.Dispose();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Thread t = new Thread(ScreenMonitor);
            ImageParam imgPara = new ImageParam();
            imgPara.a = aa;
            imgPara.b = bb;
            imgPara.c = cc;
            imgPara.d = dd;
            t.Start((ImageParam)imgPara);    
          }