let's say i have day's dropdownlist range from 1 to 31, then i also bind the dropdownlist from the database to get the day,

and the problem that i face is duplicate value show up.

let's say in database the day is 4. When bind it to dropdownlist, the 4 will be selected. but when click on the dropdownlist to select

the day to make changes or update, the 1 is missing, and there is another 4 listed. That's mean there will have double 4 in the

dropdownlist. Any idea to solve this error???

 

Check my last post:

http://forums.asp.net/thread/1416435.aspx 

and post your code. 

            string strSelect="Select * From Teacher Where TeacherID='" + strTeacherID + "'";
            SqlConnection conTeacher=new SqlConnection(strConnection);
            SqlCommand cmdSelect=new SqlCommand(strSelect,conTeacher);
            conTeacher.Open();
            SqlDataReader dtrRead=cmdSelect.ExecuteReader();
            if(dtrRead.HasRows)
            {
                while(dtrRead.Read())
                {
                    txtTeacherName.Text=dtrRead["TeacherName"].ToString();
                    txtTeacherIcno.Text=dtrRead["TeacherIcno"].ToString();
                    dropGender.SelectedItem.Text=dtrRead["TeacherGender"].ToString();
                    DateTime dtDob=Convert.ToDateTime(dtrRead["TeacherDob"]);
                    dropDobDay.SelectedItem.Text=dtDob.Day.ToString();
                    dropDobMonth.SelectedItem.Text=dtDob.Month.ToString();
                    dropDobYear.SelectedItem.Text=dtDob.Year.ToString();
                }
            }
            dtrRead.Close();
            conTeacher.Close();
 

 <asp:DropDownList ID="dropGender" Runat="server">
 <asp:ListItem>M</asp:ListItem>
 <asp:ListItem>F</asp:ListItem>
 </asp:DropDownList>

 <asp:dropdownlist id="dropDobMonth" Runat="server">
                            <asp:ListItem runat="server">1</asp:ListItem>
                            <asp:ListItem runat="server">2</asp:ListItem>
                            <asp:ListItem runat="server">3</asp:ListItem>
                            <asp:ListItem runat="server">4</asp:ListItem>
                           ....
 </asp:dropdownlist>

if the month in database is 4, the 4 will be shown as the 1st in the dropdownlist, and when you scroll it down, there is a 4 in the 4th row,

and this is same as apply to the gender part, if the char's gender is F, there will be duplicate F shown up 

dropDobDay.SelectedItem.Text=dtDob.Day.ToString();

This is the problem

Try:

 dropDobDay.SelectedItem.Text.Equals(dtDob.Day.ToString()); //Guess this wont work, that was my first idea :-)

 OR

dropDobDay.SelectedValue=dtDob.Day.ToString();

            String[] days = { "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31" };
            String[] months = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
            String[] years = { "2006", "2007", "2008" };
            ddlDays.DataSource = days;
            //Naplneni dnesnim datem
            ddlDays.SelectedValue = Convert.ToString(DateTime.Today.Day);
            ddlDaysB.DataSource = days;
            ddlDaysB.SelectedValue = Convert.ToString(DateTime.Today.AddDays(2).Day);
            ddlMonths.DataSource = months;
            ddlMonths.SelectedIndex = DateTime.Today.Month -1;
            ddlMonthsB.DataSource = months;
            ddlMonthsB.SelectedIndex = DateTime.Today.AddDays(2).Month -1;
            ddlYears.DataSource = years;
            ddlYears.SelectedValue = Convert.ToString(DateTime.Today.Year);
            ddlYearsB.DataSource = years;
            ddlYearsB.SelectedValue = Convert.ToString(DateTime.Today.AddDays(2).Year);
            DataBind();