Excel File Error After Using SaveAsDialog in C#

Question

Hello,
I have a project where I am trying to use SaveFileDialog. My code runs fine and saves the file to the directory that I choose. The problem is when I try to open the file I receive an error from Excel stating
 “Excel cannot open the file Test_File.xlsx because the file format or file extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file”
 Is there something happening in my code that is corrupting the file during the save process?
I can’t figure out why I am getting this error. Any help will be greatly appreciated.
I am working in VS 2013 Pro. and using C#. Here’s my code:
private
void btnSave_Click(object
sender, EventArgs e)
Stream saveFile;
SaveFileDialog saveFileDialog1 =
new
SaveFileDialog();           
saveFileDialog1.Title = "Save As";          
saveFileDialog1.Filter = "Excel Files (*.xlsx)| *.xlsx";
saveFileDialog1.FilterIndex = 2;
saveFileDialog1.RestoreDirectory = true;           
if (saveFileDialog1.ShowDialog() ==
DialogResult.OK)
if ((saveFile = saveFileDialog1.OpenFile()) !=
null)
// Code to write the stream goes here.
saveFile.Close();
Thank you,
Dave
David Young

Answer 1

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;
using ClosedXML.Excel;
using DocumentFormat.OpenXml;
using System.IO;
namespace LoanOrig_FDIC_Codes
public partial class Form1 : Form
SqlCommand sqlCmd;
SqlDataAdapter sqlDA;
DataSet sqlDS;
DataTable sqlDT;
SqlCommand sqlCmdCnt;
public Form1()
InitializeComponent();
//BEGIN BUTTON LOAD CLICK EVENT
private void btnLoad_Click(object sender, EventArgs e)
string sqlCon = "Data Source=FS-03246; Initial Catalog=ExtractGenerator; User ID=MyID; Password=MyPW";
//Set the 2 dateTimePickers to today's date
DateTime @endDate = End_dateTimePicker.Value.Date;
DateTime @startDate = Start_dateTimePicker.Value.Date;
//Validate the values of the 2 dateTimePickers
if (endDate < startDate)
MessageBox.Show("End Date must be greater than or equal to the Start Date OR Start Date must be less than or equal to the End Date ", "Incorrect Date Selection",MessageBoxButtons.OK,MessageBoxIcon.Error);
//Reset both dateTimePickers to todays date
Start_dateTimePicker.Value = DateTime.Today;
End_dateTimePicker.Value = DateTime.Today;
return;
//End of date validation
string sqlData = @"SELECT AcctNbr,
CurrAcctStatCD,
Org,
MJAcctTypCD,
MIAcctTypCD,
NoteOriginalBalance,
ContractDate,
FDICCATCD,
FDICCATDESC,
PropType,
PropTypeDesc
FROM I_Loans
WHERE CAST(ContractDate AS datetime) BETWEEN @startdate AND @enddate ORDER BY ContractDate";
SqlConnection connection = new SqlConnection(sqlCon);
SqlCommand sqlCmd = new SqlCommand(sqlData, connection);
sqlCmd.Parameters.AddWithValue("@startDate", startDate);
sqlCmd.Parameters.AddWithValue("@endDate", endDate);
sqlDS = new DataSet();
sqlDA = new SqlDataAdapter(sqlCmd); //SqlAdapter acts as a bridge between the DataSet and SQL Server for retrieving the data
connection.Open();
sqlDA.SelectCommand = sqlCmd; //SqlAdapter uses the SelectCommand property to get the SQL statement used to retrieve the records from the table
sqlDA.Fill(sqlDS, "I_Loans"); //SqlAdapter uses the "Fill" method so that the DataSet will match the data in the SQL table
sqlDT = sqlDS.Tables["I_Loans"];
//Code section to get record count
sqlCmdCnt = connection.CreateCommand();
sqlCmdCnt.CommandText = "SELECT COUNT(AcctNbr) AS myCnt FROM I_Loans WHERE ContractDate BETWEEN @startDate AND @endDate";
sqlCmdCnt.Parameters.AddWithValue("@startDate", startDate);
sqlCmdCnt.Parameters.AddWithValue("@endDate", endDate);
int recCnt = (int)sqlCmdCnt.ExecuteScalar();
txtRecCnt.Text = recCnt.ToString();
btnExport.Enabled = true;
btnSave.Enabled = true;
//End of code section for record count
connection.Close();
dataGridView1.DataSource = sqlDS.Tables["I_Loans"];
dataGridView1.ReadOnly = true;
//Reset both dateTimePickers to todays date
Start_dateTimePicker.Value = DateTime.Today;
End_dateTimePicker.Value = DateTime.Today;
//END BUTTON LOAD CLICK EVENT
//BEGIN BUTTON EXPORT CLICK EVENT
private void btnExport_Click(object sender, EventArgs e)
{ //ClosedXML code to export datagrid result set to Excel
string dirInfo = Path.GetPathRoot(@"\\FS-03250\users\dyoung\LoanOrig_FDIC_Codes");
if (Directory.Exists(dirInfo))
var wb = new XLWorkbook();
var ws = wb.Worksheets.Add(sqlDT);
ws.Tables.First().ShowAutoFilter = false;
wb.SaveAs(@"\\FS-03250\users\dyoung\LoanOrig_FDIC_Codes\LoanOrig_FDIC_Codes_" + DateTime.Now.ToString("yyyy-MM-dd") + ".xlsx");
MessageBox.Show("File has been exported to U:\\LoanOrig_FDIC_Codes", "File Exported", MessageBoxButtons.OK, MessageBoxIcon.Information);
//End of ClosedXML code
else
MessageBox.Show("Drive " + "U:\\Visual Studio Projects\\LoanOrig_FDIC_Codes" + " " + "not found, not accessible, or you may have invalid permissions");
return;
//END BUTTON EXPORT CLICK EVENT
private void Form1_Load(object sender, EventArgs e)
//Set dates to be today's date when the form is openend
Start_dateTimePicker.Value = DateTime.Today;
End_dateTimePicker.Value = DateTime.Today;
private void Form1_Load_1(object sender, EventArgs e)
// TODO: This line of code loads data into the 'dataSet1.I_Loans' table. You can move, or remove it, as needed.
this.i_LoansTableAdapter.Fill(this.dataSet1.I_Loans);
private void iLoansBindingSource_CurrentChanged(object sender, EventArgs e)
//BEGIN THE SAVE AS PROCESS
private void btnSave_Click_1(object sender, EventArgs e)
Stream saveFile;
SaveFileDialog saveFileDialog1 = new SaveFileDialog();
saveFileDialog1.Title = "Save As";
saveFileDialog1.Filter = "Excel Files (*.xlsx)| *.xlsx";
saveFileDialog1.FilterIndex = 1;
saveFileDialog1.RestoreDirectory = true;
if (saveFileDialog1.ShowDialog() == DialogResult.OK)
if ((saveFile = saveFileDialog1.OpenFile()) != null)
// Code to write the stream goes here.
saveFile.Close();
private void btnExit_Click(object sender, EventArgs e)
this.Close();
//END THE SAVE AS PROCESS
Here is the code for the whole project up to this point
David Young