语句已终止。将截断字符串或二进制数据。

protected void Sub_button(object sender, EventArgs e)
    {
       if (Page.IsValid)
        {
            string strConn = "provider=SQLOLEDB;data source=(LOCAL);UID=SA;PWD=*** DATABASE=test";
            OleDbConnection conn = new OleDbConnection(strConn);
            string name, realname, sex,question, answer, email;
            name = Session["username"].ToString();
            realname = TextBox1.Text.Trim();
            sex = RadioButtonList1.SelectedItem.Text.Trim();
            question = DropDownList1.SelectedItem.Text;
            answer = TextBox2.Text.Trim();
            email = TextBox3.Text.Trim();
            string sql = @"update [user] set RealName=?,Sex=?," + "Question=?,Answer=?,E_mail=? where UserName='" + name + "'";
            OleDbCommand cmd = new OleDbCommand(sql, conn);
            cmd.Parameters.Add(new OleDbParameter("@realname", OleDbType.WChar));
            cmd.Parameters.Add(new OleDbParameter("@sex", OleDbType.WChar));
            cmd.Parameters.Add(new OleDbParameter("@question", OleDbType.WChar));
            cmd.Parameters.Add(new OleDbParameter("@answer", OleDbType.WChar));
            cmd.Parameters.Add(new OleDbParameter("@email", OleDbType.WChar));
            cmd.Parameters["@realname"].Value = realname;
            cmd.Parameters["@sex"].Value = sex;
            cmd.Parameters["@question"].Value = question;
            cmd.Parameters["@answer"].Value = answer;
            cmd.Parameters["@email"].Value = email;
            conn.Open();
            cmd.ExecuteNonQuery();//此句出现语句已终止。将截断字符串或二进制数据
            conn.Close();
            Response.Redirect("main.aspx");
        }
   }
请各位帮忙！