How to import excel sheet data into PostgreSQL database table in C#

please post the total source code

I wrote below code but i am getting like this,,,,ERROR: 22021: invalid byte sequence for encoding "UTF8": 0x00



NpgsqlConnection conn = new NpgsqlConnection("Server=XXX.XX.X.XX; Port=5432; User Id=XXXX; Password=XXXXX; Database=DB_xxxx ;SyncNotification=true");
conn.Open();
NpgsqlCommand command = new NpgsqlCommand("COPY tbl_medicines(s_no,product_id,medicine_name,type_of_medicine,strength,created_date) FROM 'D:\\shared\\MedicinesNew2.csv' WITH DELIMITER ',' CSV HEADER ENCODING 'UTF8' ", conn); //WITH DELIMITER ';' CSV HEADER ENCODING 'UTF8' //with delimiter ',' csv header encoding 'WIN1252'
NpgsqlCopyIn cin = new NpgsqlCopyIn( command, conn );

Stream inStream = Console.OpenStandardInput();
// Encoding inEncoding = System.Text.Encoding.ASCII;
Encoding inEncoding = System.Text.Encoding.ASCII ;

Encoding serverEncoding = System.Text.Encoding.BigEndianUnicode; // example assumption

try
{
cin.Start();
Stream copyInStream = cin.CopyStream;
byte[] buf = new byte[9];
int i;
while( (i = inStream.Read(buf,0,buf.Length)) > 0 )
{

buf = System.Text.Encoding.Convert( inEncoding, serverEncoding, buf, 0, i );
copyInStream.Write( buf, 0, i );
}
copyInStream.Close(); // or cin.End(), if you wish
}
catch(Exception e)
{
try
{
cin.Cancel("Undo copy"); // Sends CopyFail to server
}
catch(Exception e2)
{
// we should get an error in response to our cancel request:
if( ! (""+e2).Contains("Undo copy") )
{
throw new Exception("Failed to cancel copy: " + e2 + " upon failure: " + e);
}
}
throw e;
}