ajax cascading dropdown list

am using ajax cascading dropdownlist when the page gets load i want the dropdownlist should be selected to the country which i had store in database instead of select country option what i should do for it this is my code


public CascadingDropDownNameValue[] GetCountry(string knownCategoryValues, string category)
        {

            MNBusinessLogic.Admin adm = new MNBusinessLogic.Admin();
            DataSet dsUpdate = adm.GetMasters(0, "Country", 0, true, false);
            List<CascadingDropDownNameValue> countrydetails = new List<CascadingDropDownNameValue>();
            if (dsUpdate != null && dsUpdate.Tables.Count > 0 && dsUpdate.Tables[0].Rows.Count > 0)
            {
                foreach (DataRow dtrow in dsUpdate.Tables[0].Rows)
                {
                    string CountryID = dtrow["uid"].ToString();
                    string CountryName = dtrow["MasterKey"].ToString();
                    countrydetails.Add(new CascadingDropDownNameValue(CountryName, CountryID));
                }
                
            }
            return countrydetails.ToArray();
        }

and aspx code is

 <asp:DropDownList ID="ddlC" runat="server">
         </asp:DropDownList>
          <ajaxToolkit:CascadingDropDown ID="cascadingddlC"  runat="server"                        TargetControlID="ddlC" PromptText="Select Country" LoadingText="Loading" Category="Country" ServiceMethod="GetCountry"  ServicePath="cascadingHelper.asmx">
               </ajaxToolkit:CascadingDropDown>