assign value to RadComboBox from database

[Hadoop]

I am using a form to insert data as well as to edit the data. Insertion of data is fine using telerik controls. But when I try to edit the data, 
retrieving values from the database, I am facing problem, with RadComboBox.

My form sample is ::

<table>
    <tr>
        <td>Date of Birth : </td>
        <td>
            <telerik:RadDatePicker ID="dtp_DOB" runat="server"></telerik:RadDatePicker>
        </td>
    </tr>

    <tr>
        <td>Province : </td>
        <td>
            <telerik:RadComboBox ID="rcb_province" runat="server" Sort="Ascending" AutoPostBack="true" EmptyMessage="---SELECT---"></telerik:RadComboBox>
        </td>
    </tr>
</table>

my code behind logic ::

DataTable dt = GetPersonalDetails(p_id);

    if (dt != null && dt.Rows.Count > 0)
    {
        DataRow dr = dt.Rows[0];
        string province_ = dr["province"].ToString();

        if (rcb_province.FindItemByValue(province_) != null)
        {
            rcb_province.FindItemByValue(dr["province"].ToString()).Selected = true;
        }
    }

Here I can get value in province_ from database but also if block is not executed. 

I also tried ::

if (rcb_province.FindItemByValue(dr["province"].ToString()) != null)
        {
            rcb_province.FindItemByValue(dr["province"].ToString()).Selected = true;
        }

it is also not working.

So how to set value from database to RadComboBox.

When I do,

rcb_province.Text = dr["province"].ToString();

the value is shown in the rcb_province but there is no other items in the combo box.

Please tell how to solve this problem.

Thanks!!!