RichTextBox

public partial class MyRichTextBox : RichTextBox

//打开链接
this.LinkClicked += MyRichTextBox_LinkClicked;
private void MyRichTextBox_LinkClicked(object sender, LinkClickedEventArgs e)
    {
        System.Diagnostics.Process.Start(e.LinkText);
    }

// 保存
if (System.IO.Path.GetExtension(strFilename).ToLower().Equals(".rtf"))
                this.SaveFile(strFilename);
            else
                this.SaveFile(strFilename, RichTextBoxStreamType.PlainText);

//查找
 private List<int> searchResult = new List<int>();
 public int searchString(string searchString, System.Drawing.Color color)
    {
        searchResult.Clear();

        this.Select(0, this.Text.Length);
        this.SelectionColor = System.Drawing.Color.Black;
        int index;

        //第一次搜索
        //index = this.Text.IndexOf(searchString);
        index = this.Find(searchString, RichTextBoxFinds.MatchCase);

        //这个标志是滚动到第一个搜索项
        int flag = index;

        while (index != -1)
        {
            this.Select(index, searchString.Length);
            this.SelectionColor = color;

            index = this.Find(searchString, index + 1, RichTextBoxFinds.MatchCase);
            //index = this.Text.IndexOf(searchString, index + 1);
            if (index != -1)
            {
                searchResult.Add(index);
            }
        }

        if (flag != -1)
        {
            this.Select(flag, searchString.Length);
        }
        //移动到插入符号
        this.ScrollToCaret();

        if (flag == -1)
        {
            return 0;
        }
        else
        {
            return searchResult.Count + 1;
        }
    }

    /// <summary>
    /// 滚动
    /// </summary>
    public void ScrollPosition()
    {
        if (searchResult.Count > 0)
        {
            while (this.SelectionStart > searchResult[0])
            {
                //this.Select(searchResult[0], 1);
                //this.ScrollToCaret();
                searchResult.RemoveAt(0);
            }
            this.Select(searchResult[0], 1);
            this.ScrollToCaret();
            searchResult.RemoveAt(0);
        }
        else
        {
            MessageBox.Show("已经是最后一个");
        }
    }