求助~~

Question

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
namespace zy
{    /// <summary>
    /// textclear 的摘要说明
    /// </summary>
    public class textclear
    {
        public textclear()
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }
        public void textClear(HtmlGenericControl DivId)
        {
            for (int i = 0; i < DivId.Controls.Count; i++)
            {                Control c1 = DivId.Controls[i];
                if (c1 is TextBox)
                {
                    TextBox t1 = (TextBox)c1;
                    t1.Text = "";
                }
                else if (c1 is DropDownList)
                {
                    DropDownList d1 = (DropDownList)c1;
                    d1.SelectedIndex = 0;
                }
            }
        }
    }
}
着个是类
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;public partial class _Default : System.Web.UI.Page 
{
  
 
    //钱类型计算    protected void fnum_TextChanged(object sender, EventArgs e)
    {
        addex();
    }
    protected void fnumm_TextChanged(object sender, EventArgs e)
    {
        addex();
    }
    protected void addex()
    {
        decimal num = 0.00m;
        decimal numm = 0.00m;
        if (!fnum.Text.Trim().Equals(string.Empty))
        {
            num = Convert.ToDecimal(fnum.Text.Trim());
        }
        if (!fnumm.Text.Trim().Equals(string.Empty))
        {
            numm = Convert.ToDecimal(fnumm.Text.Trim());
        }
        fsum.Text = (num + numm).ToString();
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        zy.textclear tc = new zy.textclear();
        tc.textClear(sc);
    }
}我在ASP也面里放了几个TEXTBOX,并把他门包百DIV中,DIV的ID是SC