How to Convert any Date format into sql date format

I am having one String Array which consists oif string date like 15/07/2012, where 07 is the month,I need to convert it into sql Date Formar like 2012-07-15 09:46:51.000 that is year/mm/dd and time for that I am trying use this line of code

IFormatProvider culture = new CultureInfo("en-US", true);

objar.Add(DateTime.ParseExact((s[1]), "dd-MM-yyyy HH:mm:ss.fff", culture, DateTimeStyles.None));

I am not able to get solution for the last 2 hours,please me in this reg as soon as possible.

Please have a look into my code.

private void LoadandSaveXMLData()
        {
            Date = txtDate.Text;
            ChkNDt = chkvalue + txtDate.Text;

            string ListofXMLValues = "";
            string parentElementName = "";
            string childElementName = "";
            string childElementValue = "";
            bool element = false;
            lblMsg.Text = "";

            //if XML file present in local system
            //XmlTextReader xReader = new XmlTextReader(Server.MapPath("~/POST0520120803.xml"));
            //if XML file present in Remote Server system
            //XmlTextReader xReader = new XmlTextReader("http://www.godurian.com/godurian/sth100/transfiles/POST0520120803.xml");
            XmlTextReader xReader = new XmlTextReader("http://www.godurian.com/godurian/sth100/transfiles/POST" + ChkNDt + ".xml");
           
                try
                {
                    while (xReader.Read())
                    {
                        if (xReader.NodeType == XmlNodeType.Element)
                        {
                            if (element)
                            {
                                parentElementName = parentElementName + childElementName + " ";
                                // parentElementName = parentElementName + "<br>";

                            }
                            element = true;
                            childElementName = xReader.Name;
                        }
                        else if (xReader.NodeType == XmlNodeType.Text | xReader.NodeType == XmlNodeType.CDATA)
                        {

                            element = false;
                            childElementValue = xReader.Value;
                            //lblMsg.Text = lblMsg.Text + "<b>" + parentElementName + "<br>" + childElementName + "</b><br>" + childElementValue;

                            lblMsg.Text = lblMsg.Text + "" + parentElementName + "" + childElementValue + ",";

                            //lblMsg.Text = childElementName + " " + lblMsg.Text + "" + childElementValue + ",";

                            ListofXMLValues = (lblMsg.Text);


                            parentElementName = "";
                            childElementName = "";
                        }
                        ListofXMLValues = ListofXMLValues.TrimEnd(',');
                        lblXMLList.Text = ListofXMLValues;


                    }
                    if (ListofXMLValues != "")
                    {
                        string XMLValuesWithoutPN = ListofXMLValues.Remove(0, 8);
                        string[] XMLValuesResult = Regex.Split(XMLValuesWithoutPN, "adddailyrevenue ");

                        foreach (string a in XMLValuesResult)
                        {
                            if (a != "")
                            {
                                string CurrentUser = Session["admin"].ToString();
                                string[] s = Regex.Split(a, ",");
                                IFormatProvider culture = new CultureInfo("en-US", true);
                                ArrayList objar = new ArrayList();
                                objar.Add(s[0]);
                                objar.Add(DateTime.ParseExact((s[1]), "dd-MM-yyyy HH:mm:ss.fff", culture, DateTimeStyles.None));
                                objar.Add(s[2]);
                                //objar.Add(s[3]);
                                objar.Add(DateTime.ParseExact((s[3]), "dd-MM-yyyy HH:mm:ss.fff", culture, DateTimeStyles.None));
                                objar.Add(s[4]);
                                objar.Add(s[5]);
                                objar.Add(s[6]);
                                objar.Add(s[7]);
                                objar.Add(s[8]);
                                objar.Add(s[9]);
                                objar.Add(s[10]);
                                objar.Add(s[11]);
                                objar.Add(s[12]);
                                objar.Add(s[13]);
                                objar.Add(s[14]);
                                objar.Add(s[15]);
                                objar.Add(s[16]);
                                objar.Add(s[17]);
                                objar.Add(s[18]);
                                objar.Add(s[19]);
                                objar.Add(s[20]);
                                objar.Add(s[21]);
                                objar.Add(s[22]);
                                objar.Add(s[23]);
                                objar.Add(s[24]);
                                objar.Add(CurrentUser);
                                DBUtil.DbUtilResult dbResult = DBUtil.Execute("SPInsertXMLData", objar);
                                int iResult = Convert.ToInt16(dbResult.Params["@RETURN_VALUE"]);
                                if (iResult > 0)
                                {

                                    CustomMessage.ShowMessage("Saved Sucessfully");
                                }
                                else if (iResult == 0)
                                {
                                    CustomMessage.ShowMessage("One or More Records Already Exists");
                                }
                                else
                                {
                                    CustomMessage.ShowMessage("Error in Saving");
                                }
                            }
                        }

                    }
                    xReader.Close();

                }
                
            
            
        catch (Exception)
                {

                    CustomMessage.ShowMessage("Specified file not found");
                }

        }