I want to pass the selected checkboxlist values to the another page Textbox with comma separator,

Well you can retrieve the values of checkbox, & can fetch the value from another page using either querystring or from session, an example as below:

string sValues = string.Empty;
            for (int i = 0; i <= chk.Items.Count - 1; i ++ )
            {
                if (chk.Items[i].Selected)
                {
                    sValues += chk.Items[i].Value + ",";
                }
            }

            Response.Redirect("wrox.aspx?Items=" + sValues.Substring(0,sValues.LastIndexOf(",")));
            Session["Items"] = sValues.Substring(0,sValues.LastIndexOf(","));

Regards
Mike

Fortune favours the brave, so don't regret on missed oppurtunities.