当滚动条的父控件获得焦点时，可以使用鼠标的滚动轮来控制滚动条

public partial class Form1 : Form 
{ 
    public Form1() 
    { 
        InitializeComponent(); 
        this.richTextBox1.MouseWheel += new System.Windows.Forms.MouseEventHandler(richTextBox1_MouseWheel); 
    } 

    void richTextBox1_MouseWheel(object sender, MouseEventArgs e) 
    { 
         this.Location = new System.Drawing.Point(this.Location.X, this.Location.Y + e.Delta); 
    } 
}

以上是上下卷动，要想左右卷动，可修改为以下代码：

new System.Drawing.Point(this.Location.X + e.Delta, this.Location.Y);

C#中给滚动条增加鼠标滚动轮控制事件