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How do you programmatically check if a spreadsheet has headers in C#

I am creating a winform application where every day, a user will select a xlsx file with the day's shipping information to be merged with our invoicing data.
The challenge I am having is when the user does not download the xlsx file with the specification that the winform data requires. (I wish I could eliminate this step with an API connection but sadly I cannot)
My first step is checking to see if the xlsx file has headers to that my file path is valid
Example
string connString = "provider=Microsoft.ACE.OLEDB.12.0;Data Source='" + *path* + "';Extended Properties='Excel 12.0;HDR=YES;';";
Where path is returned from an OpenFileDialog box
If the file was chosen wasn't downloaded with headers the statement above throws an exception.
If change HDR=YES; to HDR=NO; then I have trouble identifying the columns I need and if the User bothered to include the correct ones.
My code then tries to load the data into a DataTable
private void loadRows()
{
for (int i = 0; i < deliveryTable.Rows.Count; i++)
{
DataRow dr = deliveryTable.Rows[i];
int deliveryId = 0;
bool result = int.TryParse(dr[0].ToString(), out deliveryId);
if (deliveryId > 1 && !Deliveries.ContainsKey(deliveryId))
{
var delivery = new Delivery(deliveryId)
{
SalesOrg = Convert.ToInt32(dr[8]),
SoldTo = Convert.ToInt32(dr[9]),
SoldName = dr[10].ToString(),
ShipTo = Convert.ToInt32(dr[11]),
ShipName = dr[12].ToString(),
};
Which all works only if the columns are in the right place.
If they are not in the right place my thought is to display a message to the user to get the right information
Does anyone have any suggestions?
(Sorry, first time posting a question and still learning to think through it)

I guess you're loading the spreadsheet into a Datatable? Hard to tell with one line of code. I would use the columns collection in the datatable and check to see if all the columns you want are there. Sample code to enumerate the columns below.
private void PrintValues(DataTable table)
{
foreach(DataRow row in table.Rows)
{
foreach(DataColumn column in table.Columns)
{
Console.WriteLine(row[column]);
}
}
}

private void GetExcelSheetForUpload(string PathName, string UploadExcelName)
{
string excelFile = "DateExcel/" + PathName;
OleDbConnection objConn = null;
System.Data.DataTable dt = null;
try
{
DataSet dss = new DataSet();
String connString = "Provider=Microsoft.ACE.OLEDB.12.0;Persist Security Info=True;Extended Properties=Excel 12.0 Xml;Data Source=" + PathName;
objConn = new OleDbConnection(connString);
objConn.Open();
dt = objConn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
if (dt == null)
{
return;
}
String[] excelSheets = new String[dt.Rows.Count];
int i = 0;
foreach (DataRow row in dt.Rows)
{
if (i == 0)
{
excelSheets[i] = row["TABLE_NAME"].ToString();
OleDbCommand cmd = new OleDbCommand("SELECT * FROM [" + excelSheets[i] + "]", objConn);
OleDbDataAdapter oleda = new OleDbDataAdapter();
oleda.SelectCommand = cmd;
oleda.Fill(dss, "TABLE");
}
i++;
}
grdExcel.DataSource = dss.Tables[0].DefaultView;
grdExcel.DataBind();
lblTotalRec.InnerText = Convert.ToString(grdExcel.Rows.Count);
}
catch (Exception ex)
{
ViewState["Fuletypeidlist"] = "0";
grdExcel.DataSource = null;
grdExcel.DataBind();
}
finally
{
if (objConn != null)
{
objConn.Close();
objConn.Dispose();
}
if (dt != null)
{
dt.Dispose();
}
}
}
if (grdExcel.HeaderRow.Cells[0].Text.ToString() == "CODE")
{
GetExcelSheetForEmpl(PathName);
}
else
{
divStatusMsg.Style.Add("display", "");
divStatusMsg.Attributes.Add("class", "alert alert-danger alert-dismissable");
divStatusMsg.InnerText = "ERROR !!... Upload Excel Sheet in header Defined Format ";
}

Calculate Excel value before import to SQL Server

I have problem about import to SQL Server, the scenario is to import excel file and calculate the value in column 3 and 4 (produce column 5) of the imported excel file. In my case, the calculation is in C#, not in excel. And then import to SQL Server (ASP.Net + C#). Any idea how to do this ?
This is my code (it's still give me error)
protected void btnImport_Click(object sender, EventArgs e)
{
if (FileUpload1.HasFile)
{
string FileName = Path.GetFileName(FileUpload1.PostedFile.FileName);
string Extension = Path.GetExtension(FileUpload1.PostedFile.FileName);
if (Extension == ".xlsx")
{
string path = string.Concat((Server.MapPath("~/tampung/" + FileUpload1.FileName)));
FileUpload1.PostedFile.SaveAs(path);
//make connection to excel workBook
using (OleDbConnection oledbcon = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=Excel 12.0;"))
{
OleDbCommand cmd = new OleDbCommand("SELECT * FROM [Sheet1$]", oledbcon);
OleDbDataAdapter ObjAdapter1 = new OleDbDataAdapter(cmd);
oledbcon.Open();
using (DbDataReader dr = cmd.ExecuteReader())
{
DataTable DT = new DataTable();
DT.Load(dr);
for (int i = 0; i < DT.Rows.Count; i++)
{
string Year = DT.Rows[i][0].ToString();
string StudentName = DT.Rows[i][1].ToString();
string Semester = DT.Rows[i][2].ToString();
decimal Value1 = Convert.ToDecimal(DT.Rows[i][3]);
decimal Value2 = Convert.ToDecimal(DT.Rows[i][4]);
decimal AverageValue = Convert.ToDecimal((Value1 + Value2) / 2);
}
string conString = #"Data Source=PETRELLI;Initial Catalog=demo;Integrated Security=True";
SqlBulkCopy bulkInsert = new SqlBulkCopy(conString);
bulkInsert.DestinationTableName = "student";
bulkInsert.WriteToServer(dr);
oledbcon.Close();
Array.ForEach(Directory.GetFiles(Server.MapPath("~/temp/")), File.Delete);
Label1.Text = "Succeeded";
}
}
}
else
{
Label1.Text = "Hi, it's error";
}
}
else
{
Label1.Text = "Please choose the right file excel";
}
}

The error should be coming from this line
bulkInsert.WriteToServer(dr);
This is happening because DT.Load(dr), that you called earlier, have looped through the dr already and has moved the pointer to the end, after which you can not use the dr again.
DT.Load(dr); //<-- this line already looped through the dr. dr can't be used after this line
Solution
Use the DT instead of dr since you already have DT populated with the required data by calling DT.Load(dr)

How can I read the rows of an Excel csv or xls file into an ASP.NET app from a remote location using C#?

Here's my situation. I'm designing a program that takes Excel files (which may be in csv, xls, or xlsx format) from a remote network drive, processes the data, then outputs and stores the results of that process. The program provides a listbox of filenames that are obtained from the remote network drive folder using the method detailed in the accepted answer here. Once the user selects a filename from the listbox, I want the program to find the file and obtain the information from it to do the data processing. I have tried using this method to read the data from the Excel file while in a threaded security context, but that method just fails without giving any kind of error. It seems to not terminate. Am I going about this the wrong way?
Edit - (Final Notes: I have taken out the OleDbDataAdapter and replaced it with EPPlus handling.)
I was able to scrub sensitive data from the code, so here it is:
protected void GetFile(object principalObj)
{
if (principalObj == null)
{
throw new ArgumentNullException("principalObj");
}
IPrincipal principal = (IPrincipal)principalObj;
Thread.CurrentPrincipal = principal;
WindowsIdentity identity = principal.Identity as WindowsIdentity;
WindowsImpersonationContext impersonationContext = null;
if (identity != null)
{
impersonationContext = identity.Impersonate();
}
try
{
string fileName = string.Format("{0}\\" + Files.SelectedValue, #"RemoteDirectoryHere");
string connectionString = string.Format("Provider=Microsoft.ACE.OLEDB.14.0; data source={0}; Extended Properties=Excel 14.0;", fileName);
OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT * FROM Sheet1", connectionString);
DataSet ds = new DataSet();
adapter.Fill(ds, "Sheet1");
dataTable = ds.Tables["Sheet1"];
}
finally
{
if (impersonationContext != null)
{
impersonationContext.Undo();
}
}
}
Additional Edit
Now xlsx files have been added to the mix.
Third Party
Third party solutions are not acceptable in this case (unless they allow unrestricted commercial use).
Attempts - (Final Notes: Ultimately I had to abandon OleDb connections.)
I have tried all of the different connection strings offered, and I have tried them with just one file type at a time. None of the connection strings worked with any of the file types.
Permissions
The User does have access to the file and its directory.

Your connection string might be the issue here. As far as I know, there isn't 1 that can read all xls, csv, and xlsx. I think you're using the XLSX connection string.
When I read xls, i use the following connection string:
#"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + sFilePath + ";Extended Properties='Excel 8.0;HDR=YES;IMEX=1;'"
Having said that, I recommend using a 3rd party file reader/parser to read XLS and CSV since, from my experience, OleDbDataAdapter is wonky depending on the types of data that's being read (and how mixed they are within each column).
For XLS, try NPOI https://code.google.com/p/npoi/
For CSV, try http://www.codeproject.com/Articles/9258/A-Fast-CSV-Reader
For XLSX, try EPPlus http://epplus.codeplex.com/
I've had great success with the above libraries.

Is it really important that you use an OleDb interface for this? I've always done it with Microsoft.Office.Excel.Interop, to wit:
using System;
using Microsoft.Office.Interop.Excel;
namespace StackOverflowExample
{
class Program
{
static void Main(string[] args)
{
var app = new Application();
var wkbk = app.Workbooks.Open(#"c:\data\foo.xls") as Workbook;
var wksht = wkbk.Sheets[1] as Worksheet; // not zero-based!
for (int row = 1; row <= 100; row++) // not zero-based!
{
Console.WriteLine("This is row #" + row.ToString());
for (int col = 1; col <= 100; col++)
{
Console.WriteLine("This is col #" + col.ToString());
var cell = wksht.Cells[row][col] as Range;
if (cell != null)
{
object val = cell.Value;
if (val != null)
{
Console.WriteLine("The value of the cell is " + val.ToString());
}
}
}
}
}
}
}

As you will be dealing with xlsx extension, you should rather opt for the new connection string.
public static string getConnectionString(string fileName, bool HDRValue, bool WriteExcel)
{
string hdrValue = HDRValue ? "YES" : "NO";
string writeExcel = WriteExcel ? string.Empty : "IMEX=1";
return "Provider=Microsoft.ACE.OLEDB.12.0;" + "Data Source=" + fileName + ";" + "Extended Properties=\"Excel 12.0 xml;HDR=" + hdrValue + ";" + writeExcel + "\"";
}
Above is the code for getting the connection string. First argument expects the actual path for file location. Second argument will decide whether to consider first row values as column headers or not. Third argument helps decide whether you want to open the connection to create and write the data or simply read the data. To read the data set it to "FALSE"
public static ReadData(string filePath, string sheetName, List<string> fieldsToRead, int startPoint, int endPoint)
{
DataTable dt = new DataTable();
try
{
string ConnectionString = ProcessFile.getConnectionString(filePath, false, false);
using (OleDbConnection cn = new OleDbConnection(ConnectionString))
{
cn.Open();
DataTable dbSchema = cn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
if (dbSchema == null || dbSchema.Rows.Count < 1)
{
throw new Exception("Error: Could not determine the name of the first worksheet.");
}
StringBuilder sb = new StringBuilder();
sb.Append("SELECT *");
sb.Append(" FROM [" + sheetName + fieldsToRead[0].ToUpper() + startPoint + ":" + fieldsToRead[1].ToUpper() + endPoint + "] ");
OleDbDataAdapter da = new OleDbDataAdapter(sb.ToString(), cn);
dt = new DataTable(sheetName);
da.Fill(dt);
if (dt.Rows.Count > 0)
{
foreach (DataRow row in dt.Rows)
{
string i = row[0].ToString();
}
}
cn.Dispose();
return fileDatas;
}
}
catch (Exception)
{
}
}

This is for reading 2007 Excel into dataset
DataSet ds = new DataSet();
try
{
string myConnStr = "";
myConnStr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=MyDataSource;Extended Properties=\"Excel 12.0;HDR=YES\"";
OleDbConnection myConn = new OleDbConnection(myConnStr);
OleDbCommand cmd = new OleDbCommand("select * from [Sheet1$] ", myConn);
OleDbDataAdapter adapter = new OleDbDataAdapter();
adapter.SelectCommand = cmd;
myConn.Open();
adapter.Fill(ds);
myConn.Close();
}
catch
{ }
return ds;

Unable to read excel sheet using ExcelReader in ASP.Net?

I am using IExcelDataReader to reader to read a excel sheet using following code:
private static IExcelDataReader FetchDataReaderForExcel(HttpPostedFile file)
{
IExcelDataReader dataReader = null;
if (null != file)
{
string fileExtension = Path.GetExtension(file.FileName);
switch (fileExtension)
{
case ".xls":
dataReader = ExcelReaderFactory.CreateBinaryReader(file.InputStream);
break;
case ".xlsx":
dataReader = ExcelReaderFactory.CreateOpenXmlReader(file.InputStream);
break;
default:
dataReader = null;
break;
}
}
return dataReader;
}
When i am reading the excel sheet using this method sometime i am not able to read the data correctly. Sometime it is not able to read column other time it is not able to read the entire data. I need to format each column to normal text and then upload again, it works then. Excel contains data contains integer, string, datetime, hyperlink. Can anyone tell me what could be the problem or alternative for this?

I'm using oledb and it works perfect for me. Here is my example:
using (OleDbConnection con = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + Filename + ";Extended Properties=\"Excel 12.0 Xml;HDR=YES\""))
{
//
string listName = "Sheet1";
con.Open();
try
{
DataSet ds = new DataSet();
OleDbDataAdapter odb = new OleDbDataAdapter("select * from [" + listName + "$]", con);
odb.Fill(ds);
con.Close();
foreach (DataRow myrow in ds.Tables[0].Rows)
{
Object[] cells = myrow.ItemArray;
if (cells[0].ToString().Length > 0 || cells[1].ToString().Length > 0 || cells[2].ToString().Length > 0)
{
/*
cells[0]
cells[1]
cells[2]
are getting values
*/
}
}
}
catch (Exception ex)
{
return null;
}
}
OLEDB.12.0 works with both .xls and .xlsx

If you are Uploading the file ,and the file has Many sheets in it and you want to read all the sheets you can follow this method....first write the Code for FileUPload and save the uploaded file in a path....using that path you can read the files
/// <summary>
/// This method retrieves the excel sheet names from
/// an excel workbook & reads the excel file
/// </summary>
/// <param name="excelFile">The excel file.</param>
/// <returns></returns>
#region GetsAllTheSheetNames of An Excel File
public static string[] ExcelSheetNames(String excelFile)
{
DataTable dt;
string connString = #"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + excelFile + ";Extended Properties='Excel 12.0;HDR=Yes'";
using (OleDbConnection objConn = new OleDbConnection(connString))
{
objConn.Open();
dt =
objConn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
if (dt == null)
{
return null;
}
string[] res = new string[dt.Rows.Count];
for (int i = 0; i < res.Length; i++)
{
string name = dt.Rows[i]["TABLE_NAME"].ToString();
if (name[0] == '\'')
{
//numeric sheetnames get single quotes around
//remove them here
if (Regex.IsMatch(name, #"^'\d\w+\$'$"))
{
name = name.Substring(1, name.Length - 2);
}
}
res[i] = name;
}
return res;
}
}
#endregion
//You can read files and store the data in a dataset use them
public static DataTable GetWorksheet(string excelFile,string worksheetName)
{
string connString = #"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + excelFile + ";Extended Properties='Excel 12.0;HDR=Yes'";
OleDbConnection con = new System.Data.OleDb.OleDbConnection(connString);
OleDbDataAdapter cmd = new System.Data.OleDb.OleDbDataAdapter("select * from [" + worksheetName + "$]", con);
con.Open();
System.Data.DataSet excelDataSet = new DataSet();
cmd.Fill(excelDataSet);
con.Close();
return excelDataSet.Tables[0];
}
Else U can use this method to read the excel file
Just Add the reference
click on the "AddReference" on solution explorer ,click on com tab and Add this reference
Microsoft.Office.Interop.Excel
And add this namespace in your code behind
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Excel = Microsoft.Office.Interop.Excel;
using System.IO;
using System.Data;
static void Main(string[] args)
{
string Path = #"C:\samples\SEP DUMPS.xls";
// initialize the Excel Application class
Excel.Application app = new Excel.Application();
//Excel.Worksheet NwSheet;
Excel.Range ShtRange;
// create the workbook object by opening the excel file.
Excel.Workbook workBook = app.Workbooks.Open(Path,0,true,5,"","",true,Excel.XlPlatform.xlWindows,"\t",false,false, 0,true,1,0);
// Get The Active Worksheet Using Sheet Name Or Active Sheet
Excel.Worksheet workSheet = (Excel.Worksheet)workBook.ActiveSheet;
int index = 1;
// that is which cell in the excel you are interesting to read.
object rowIndex = 1;
object colIndex1 = 1;
object colIndex2 = 5;
object colIndex3 = 4;
System.Text.StringBuilder sb = new StringBuilder();
try
{
while (((Excel.Range)workSheet.Cells[rowIndex, colIndex1]).Value2 != null)
{
rowIndex =index;
string firstName = Convert.ToString( ((Excel.Range)workSheet.Cells[rowIndex, colIndex1]).Value2);
string lastName = Convert.ToString(((Excel.Range)workSheet.Cells[rowIndex, colIndex2]).Value2);
string Name = Convert.ToString(((Excel.Range)workSheet.Cells[rowIndex, colIndex3]).Value2);
string line = firstName + "," + lastName + "," + Name;
sb.Append(line); sb.Append(Environment.NewLine);
Console.WriteLine(" {0},{1},{2} ", firstName, lastName,Name);
index++;
}
Writetofile(sb.ToString());
ShtRange = workSheet.UsedRange;
Object[,] s = ShtRange.Value;
}
catch (Exception ex)
{
app.Quit();
Console.WriteLine(ex.Message);
Console.ReadLine();
}
}
Hope this helps you..........If u have any doubts Ask me...

Reading columns from Excel, reformat cells

I am currently trying to read in cells from an excel spread sheet, and it seems to reformat cells when I don't want it to. I want it to come through as plan text. I have read a couple of solutions to this problem and I have implemented them, but I am still having the same issue.
The reader turns dates in numbers and numbers into dates.
Example:
Friday, January 29, 2016 comes out to be : 42398
and
40.00 comes out to be : 2/9/1900 12:00:00 AM
code:
string stringconn = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + files[0] + ";Extended Properties=\"Excel 12.0;IMEX=1;HDR=NO;TypeGuessRows=0;ImportMixedTypes=Text\"";
try {
OleDbConnection conn = new OleDbConnection(stringconn);
OleDbDataAdapter da = new OleDbDataAdapter("SELECT * FROM [CUAnswers$]", conn);
DataTable dt = new DataTable();
try {
printdt(dt);
I have tried
IMEX=0;
HDR=NO;
TypeGuessRows=1;
This is how I am printing out the sheet
public void printdt(DataTable dt) {
int counter1 = 0;
int counter2 = 0;
string temp = "";
foreach (DataRow dataRow in dt.Rows) {
foreach (var item in dataRow.ItemArray) {
temp += " ["+counter1+"]["+counter2+"]"+ item +", ";
counter2++;
}
counter1++;
logger.Debug(temp);
temp = "";
counter2 = 0;
}
}

I had a similar problem, except it was using Interop to read the Excel spreadsheet. This worked for me:
var value = (range.Cells[rowCnt, columnCnt] as Range).Value2;
string str = value as string;
DateTime dt;
if (DateTime.TryParse((value ?? "").ToString(), out dt))
{
// Use the cell value as a datetime
}
Editted to add new ideas
I was going to suggest saving the spreadsheet as comma-separated values. Then Excel converts the cells to text. It is easy to parse a CSV in C#.
That led me to think of how to programmatically do the conversion, which is covered in Convert xls to csv programmatically. Maybe the code in the accepted answer is what you are looking for:
string ExcelFilename = "c:\\ExcelFile.xls";
DataTable worksheets;
string connectionString = #"Provider=Microsoft.Jet.OLEDB.4.0;" + #"Data Source=" + ExcelFilename + ";" + #"Extended Properties=""Excel 8.0;HDR=Yes;IMEX=1""";
using (OleDbConnection connection = new OleDbConnection(connectionString))
{
connection.Open();
worksheets = connection.GetSchema("Tables");
foreach (DataRow row in worksheets.Rows)
{
// For Sheets: 0=Table_Catalog,1=Table_Schema,2=Table_Name,3=Table_Type
// For Columns: 0=Table_Name, 1=Column_Name, 2=Ordinal_Position
string SheetName = (string)row[2];
OleDbCommand command = new OleDbCommand(#"SELECT * FROM [" + SheetName + "]", connection);
OleDbDataAdapter oleAdapter = new OleDbDataAdapter();
oleAdapter.SelectCommand = command;
DataTable dt = new DataTable();
oleAdapter.FillSchema(dt, SchemaType.Source);
oleAdapter.Fill(dt);
for (int r = 0; r < dt.Rows.Count; r++)
{
string type1 = dr[1].GetType().ToString();
string type2 = dr[2].GetType().ToString();
string type3 = dr[3].GetType().ToString();
string type4 = dr[4].GetType().ToString();
string type5 = dr[5].GetType().ToString();
string type6 = dr[6].GetType().ToString();
string type7 = dr[7].GetType().ToString();
}
}
}