string whereClause = string.Empty;

        foreach (遍历CheckBoxList)
        {

            if (选中)
            {
                if (whereClause == string.Empty)
                    whereClause += "'" + 取值 + "'";
                else
                    whereClause += ",'" + 取值 + "'";
            }
        }
        if (whereClause != string.Empty)
        {
            SqlConnection cn = new SqlConnection(...);
            string strSQL = "delete from mytable where id in (" + whereClause + ")";
            SqlCommand cmd = new SqlCommand(strSQL, cn);
            cn.Open();
            cmd.ExecuteNonQuery();
            cn.Close();
        }