How to remove empty rows from DataTable

This will remove all empty rows from datable:

DataTable dt = dt.Rows
                 .Cast<DataRow>()
                 .Where(row => !row.ItemArray.All(f => f is DBNull))
                 .CopyToDataTable();

OR

DataTable dt = dt.Rows
                 .Cast<DataRow>()
                 .Where(row => !row.ItemArray.All(f => f is DBNull || 
                                  string.IsNullOrEmpty(f as string ?? f.ToString())))
                 .CopyToDataTable();

Try this.

public bool InsertRowsToDataBase()
{
    try
    {
        DataTable excelTable = new DataTable();

        string connString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source='" + txtExcelFile.Text + "';Extended Properties= 'Excel 8.0;HDR=Yes;IMEX=1'";
        using (OleDbConnection cnn = new OleDbConnection(connString))
        {
            string query = "select * from [Customers$]";
            using (OleDbDataAdapter data = new OleDbDataAdapter(query, cnn))
            {
                data.Fill(excelTable);
            }
        }
        dgvCustomers.ColumnHeadersVisible = false;

        connString = "Data Source=COMPUTER-8EB749;Initial Catalog=KITS;Integrated Security=true";
        using (SqlConnection connection = new SqlConnection(connString))
        {
            connection.Open();
            for (int i = 0; i < excelTable.Rows.Length; i++)
            {
                //takes from the 3rd row
                if (i > 1)
                {
                    DataRow row = excelTable.Rows[i];
                    object ID = row[0];
                    if (ID != null && !String.IsNullOrEmpty(ID.ToString().Trim()))
                    {
                        Int16 CustID = Convert.ToInt16(ID);
                        string CustName = row[1].ToString();
                        string CardScheme = row[2].ToString();
                        string Outlet = row[3].ToString();
                        string TerminalNum = row[4].ToString();
                        Int32 Terminal = Convert.ToInt32(TerminalNum);
                        string Date1 = row[5].ToString();
                        DateTime Date = Convert.ToDateTime(Date1);
                        string Time = row[6].ToString();
                        DateTime DateTime = Convert.ToDateTime(Time);
                        string Amount1 = row[7].ToString();
                        double Amount = Convert.ToDouble(Amount1);

                        string columnNames = "CustID,CustName,CardScheme,Outlet,TerminalNum,TranDate,TranDateTime,Amount";
                        string query = String.Format("insert into Customer(0}) values ('{1}', '{2}','{3}','{4}','{5}','{6}','{7}','{8}')",
                            columnNames, CustID, CustName, CardScheme, Outlet, Terminal, Date, DateTime, Amount);
                        using (SqlCommand com = new SqlCommand(query, connection))
                        {
                            com.ExecuteNonQuery();
                        }
                    }
                }
                //this is your last row. do whatever you want with this
                DataRow lastRow = excelTable.Rows[excelTable.Rows.Count - 1];
            }
        }
        return true;
    }
    catch (Exception exception)
    {
        Elmah.ErrorSignal.FromCurrentContext().Raise(exception);
        return false;
    }
}

Please note that I am just checking if ID is null and not inserting any such rows as ID will be the PK in your table.

This will remove all rows that which each of it's columns contain either nothing or white space:

dataTable = dataTable.Rows
    .Cast<DataRow>()
    .Where(row => !row.ItemArray.All(field => field is DBNull || 
                                     string.IsNullOrWhiteSpace(field as string)))
    .CopyToDataTable();