public void LoadExcelData()

        {

            string fileName = "@"C:\AdisGroup\Contacts\contacts.xls";

            //if you are using file upload control in sharepoint get the full path as follows assuming fileUpload1 is control instance

            //string fileName = fileUpload1.PostedFile.FileName

  

            string fileExtension = Path.GetExtension(fileName).ToUpper();

            string connectionString = "";

  

            if (fileExtension == ".XLS")

            {

                connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source='" + fileName + "'; Extended Properties='Excel 8.0;HDR=YES;'";

            }

            else if (fileExtension == ".XLSX")

            {

                connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source='" + fileName + "';Extended Properties='Excel 12.0 Xml;HDR=YES;'";

            }

            if (!(string.IsNullOrEmpty(connectionString)))

            {

                string[] sheetNames = GetExcelSheetNames(connectionString);

                if ((sheetNames != null) && (sheetNames.Length > 0))

                {

                    DataTable dt = null;

                    OleDbConnection con = new OleDbConnection(connectionString);

                    OleDbDataAdapter da = new OleDbDataAdapter("SELECT * FROM [" + sheetNames[0] + "]", con);

                    dt = new DataTable();

                    da.Fill(dt);

                    InsertIntoList(dt,"ContactList");

                }

            }

        }

private string[] GetExcelSheetNames(string strConnection)

        {

            var connectionString = strConnection;

            String[] excelSheets;

            using (var connection = new OleDbConnection(connectionString))

            {

                connection.Open();

                var dt = connection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);

                if (dt == null)

                {

                    return null;

                }

                excelSheets = new String[dt.Rows.Count];

                int i = 0;

  

                // Add the sheet name to the string array.

                foreach (DataRow row in dt.Rows)

                {

                    excelSheets[i] = row["TABLE_NAME"].ToString();

                    i++;

                }

            }

            return excelSheets;

        }

  

        private void InsertIntoList(DataTable listTable, string contactListName)

        {

  

            SPWeb mySite = null;

            try

            {

  

                mySite = SPContext.Current.Web; //create web object if context is null

                mySite.AllowUnsafeUpdates = true;

                SPList contactList = mySite.Lists[contactListName];

                for (int iRow = 0; iRow < listTable.Rows.Count; iRow++)

                {

                    SPListItem newContact = contactList.Items.Add();

                    newContact["FirstName"] = Convert.ToString(listTable.Rows[iRow][0]);

                    newContact["LastName"] = Convert.ToString(listTable.Rows[iRow][1]);

                    newContact["FullName"] = Convert.ToString(listTable.Rows[iRow][2]);

                    newContact["LoginID"] = Convert.ToString(listTable.Rows[iRow][3]);

                    newContact["EmailAddress"] = Convert.ToString(listTable.Rows[iRow][4]);

                    newContact["PhoneNumber"] = Convert.ToString(listTable.Rows[iRow][5]);

                    newContact["Company"] = Convert.ToString(listTable.Rows[iRow][6]);

                    newContact.Update();

                }

                mySite.AllowUnsafeUpdates = false;

            }

            catch (Exception ex)

            {

                //log exception

            }

            finally

            {

                if (mySite != null) //don't dispose if the site is from SPContext

                {

                    mySite.AllowUnsafeUpdates = false;

                }

            }