窗体的代码.....
namespace Test4_1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void numericUpDown1_ValueChanged(object sender, EventArgs e)
        {
            this.trackBar1.Value = (int)this.numericUpDown1.Value;
        }

        private void trackBar1_Scroll(object sender, EventArgs e)
        {
            this.numericUpDown1.Value = this.trackBar1.Value;
        }

        private void numericUpDown1_MouseDown(object sender, MouseEventArgs e)
        {
            this.trackBar1.Value = (int)this.numericUpDown1.Value;
        }
    }
}
但是下面的代码也可以实现上面窗口....
namespace Test4_1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void numericUpDown1_ValueChanged(object sender, EventArgs e)
        {
            this.trackBar1.Value = (int)this.numericUpDown1.Value;
        }

        private void trackBar1_Scroll(object sender, EventArgs e)
        {
            this.numericUpDown1.Value = this.trackBar1.Value;
        }

    }
}
请问红色部分的代码是什么意思...有什么作用的啊！

知道了咯.....红色代码部分就是用鼠标移动trackBar1会使numericUpDown1的数值变化

No~~~~红色部分是指点击numericUpDown1右边的上下小按钮使里面的值相应增加或减少，即这样也使得里面的值改变，所以功能和
private void numericUpDown1_ValueChanged(object sender, EventArgs e)
        {
            this.trackBar1.Value = (int)this.numericUpDown1.Value;
        }
有些重复。

我感觉也是啊...但是教材上面就是这样写的...