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Excel column data making alphabet values blank using asp.net

While uploading Excel there are values in columns in alphabets, so taking into datatable the values are getting blank.
below is the code which is making it blank.
string filename = Path.GetFileName(fluploadData.FileName);
// FileUpload.SaveAs(Server.MapPath("~/") + filename);
string filenamewithoutrext = string.Empty;
FileExt = Path.GetExtension(fluploadData.FileName).ToLower();
if (Path.GetExtension(fluploadData.FileName).ToLower() != ".xls" &&
Path.GetExtension(fluploadData.FileName).ToLower() != ".xlsx"
)
{
Response.Write("Only .xls,.xlsx are allowed.!");
return;
}
filenamewithoutrext = Path.GetFileNameWithoutExtension(fluploadData.FileName).ToLower();
string path = Server.MapPath("UploadData\\");
string filename_ = filenamewithoutrext;
// DeleteDirectory(path);
if (!Directory.Exists(path)) // CHECK IF THE FOLDER EXISTS. IF NOT, CREATE A NEW FOLDER.
{
Directory.CreateDirectory(path);
}
else
{
foreach (string file in Directory.GetFiles(path))
{
File.Delete(file);
}
}
string fname;
fname = path + filename_ + ".xls";
fluploadData.SaveAs(fname);
HttpContext.Current.Session["ExcelFilePath"] = fname;
string conStr = "";
System.Data.DataTable dtExcelRows = new System.Data.DataTable();
switch (FileExt)
{
case ".xls": //Excel 97-03
conStr = System.Configuration.ConfigurationManager.ConnectionStrings["Excel03ConString"].ConnectionString;
break;
case ".xlsx": //Excel 07
conStr = System.Configuration.ConfigurationManager.ConnectionStrings["Excel07ConString"].ConnectionString;
break;
}
conStr = String.Format(conStr, fname, "YES");
System.Data.OleDb.OleDbConnection connExcel = new System.Data.OleDb.OleDbConnection(conStr);
System.Data.OleDb.OleDbCommand cmdExcel = new System.Data.OleDb.OleDbCommand();
System.Data.OleDb.OleDbDataAdapter oda = new System.Data.OleDb.OleDbDataAdapter();
cmdExcel.Connection = connExcel;
connExcel.Open();
System.Data.DataTable dtExcelSchema = connExcel.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Tables, null);
System.Data.DataTable dtExcelColumnsTable = connExcel.GetSchema("Columns");
//string SheetName = dtExcelSchema.Rows[0]["TABLE_NAME"].ToString().Replace('\'', ' ').Trim();
string SheetName = dtExcelSchema.Rows[0]["TABLE_NAME"].ToString().Trim();
cmdExcel.CommandText = "SELECT * From [" + SheetName + "]";
oda.SelectCommand = cmdExcel;
oda.Fill(dtExcelRows);
connExcel.Close();

The problem is likely caused by mixed datatypes in a column. For example the first few rows have a number value so it is then presumed to be a column with a numeric type. When a non numeric value is encountered it can't be parsed and is ignored.
See this answer for some ways around this. They may include setting a value of IMEX=1 in the connection string or treating the header row as data (HDR=0) - assuming your column names are non numeric.
You might also want to look into specific libraries which are designed for reading/writing Excel Documents, I have had good experiences with EPPlus but it only works for .xlsx files not .xls, NPOI which I haven't used can do both.
As others have mentioned if you are just using the Excel document as a datasource for the applications it may be better to look into an alternative solution such as SQL. If you have a requirement to process spreadsheets from third parties obviously that would not be an option.

Excel to DataGridView

Additional information: The Microsoft Office Access database engine could not find the object 'C:\Users\username\Documents\sampleData.xls'. Make sure the object exists and that you spell its name and the path name correctly.
The Error is highlighted at
theDataAdapter.Fill(spreadSheetData);
Here's the sample data I used (tried in .csv , .xls , .xlsx )
Name Age Status Children
Johnny 34 Married 3
Joey 21 Single 1
Michael 16 Dating 0
Smith 42 Divorced 4
Here's the code associated:
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.IO;
using System.Data.OleDb;
namespace uploadExcelFile
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void btnImport_Click(object sender, EventArgs e)
{
var frmDialog = new System.Windows.Forms.OpenFileDialog();
if (frmDialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
string strFileName = frmDialog.FileName;
System.IO.FileInfo spreadSheetFile = new System.IO.FileInfo(strFileName);
scheduleGridView.DataSource = spreadSheetFile.ToString();
System.Diagnostics.Debug.WriteLine(frmDialog.FileName);
System.Diagnostics.Debug.WriteLine(frmDialog.SafeFileName);
String name = frmDialog.SafeFileName;
String constr = String.Format(#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=""Excel 12.0 Xml;HDR=YES""", frmDialog.FileName);
OleDbConnection myConnection = new OleDbConnection(constr);
OleDbCommand onlineConnection = new OleDbCommand("SELECT * FROM [" + frmDialog.FileName + "]", myConnection);
myConnection.Open();
OleDbDataAdapter theDataAdapter = new OleDbDataAdapter(onlineConnection);
DataTable spreadSheetData = myConnection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
theDataAdapter.Fill(spreadSheetData);
scheduleGridView.DataSource = spreadSheetData;
}
}
}
}
scheduleGridView is the DataGridViews name, & btnImport is the name for the import Button.
I've installed 2007 Office System Driver: Data Connectivity Components; which gave me the AccessDatabaseEngine.exe, but from there I've been stuck here without understanding how to get around this. It should go without saying that the filepath is correct in its entirety. There is no odd characters in the path name either (spaces, underlines, etc)
Mini Update :: (another dead end it seems like)
Although the initial error says, "could not find the object 'C:\Users\username\Documents\sampleData.xls'"
In the Debugger the exception is read as
When I look at details the exception as "C:\Users\username\Documents\sampleData.xls"
So I thought the error was that it wasn't taking the path as a literal, but this article C# verbatim string literal not working. Very Strange backslash always double
Shows very clearly that that is not my issue.

I am guessing you may be mistaken by what is returned from the following line of code…
DataTable spreadSheetData = myConnection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
The DataTable returned from this line will have nine (9) columns (TABLE_CATALOG, TABLE_SCHEMA, TABLE_NAME, TABLE_TYPE, TABLE_GUID, DESCRIPTION, TABLE_PROPID, DATE_CREATED and DATE_MODIFIED). This ONE (1) DataTable returned simply “Describes” the worksheet(s) and named range(s) in the entire selected Excel workbook. Each row in this DataTable represent either a worksheet OR a named range. To distinguish worksheets from named ranges, the “TABLE_NAME” column in this DataTable has the name of the worksheet or range AND ends each “Worksheet” Name with a dollar sign ($). If the “TABLE_NAME” value in a row does NOT end in dollar sign, then it is a range and not a worksheet.
Therefore, when the line
OleDbDataAdapter theDataAdapter = new OleDbDataAdapter(onlineConnection);
Blows up and says it cannot file the “filename” error… is somewhat expected because this line is looking for a “worksheet” name, not a filename. On the line creating the select command…
OleDbCommand onlineConnection = new OleDbCommand("SELECT * FROM [" + frmDialog.FileName + "]", myConnection);
This is incorrect; you have already selected the filename and open the file with
String constr = String.Format(#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=""Excel 12.0 Xml;HDR=YES""", frmDialog.FileName);
OleDbConnection myConnection = new OleDbConnection(constr);
myConnection.Open();
The correct OleDbCommand line should be…
OleDbCommand onlineConnection = new OleDbCommand("SELECT * FROM [" + sheetName + "]", myConnection);
The problem here is that the current code is not getting the worksheet names. Therefore, we cannot “select” the worksheet from the workbook then fill the adapter with the worksheet.
The other issue is setting the DataGridView’s DataSource to spreadSheetData… when you get the worksheet(s) from an Excel “Workbook”, you must assume there will be more than one sheet. Therefore a DataSet will work as a container to hold all the worksheets in the workbook. Each DataTable in the DataSet would be a single worksheet and it can be surmised that the DataGridView can only display ONE (1) of these tables at a time. Given this, below are the changes described along with an added button to display the “Next” worksheet in the DataGridView since there may be more than one worksheet in the workbook. Hope this makes sense.
int sheetIndex = 0;
DataSet ds = new DataSet();
public Form1() {
InitializeComponent();
}
private void btnImport_Click(object sender, EventArgs e) {
var frmDialog = new System.Windows.Forms.OpenFileDialog();
if (frmDialog.ShowDialog() == System.Windows.Forms.DialogResult.OK) {
String constr = String.Format(#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=""Excel 12.0 Xml;HDR=YES""", frmDialog.FileName);
OleDbConnection myConnection = new OleDbConnection(constr);
myConnection.Open();
DataTable spreadSheetData = myConnection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
string sheetName = "";
DataTable dt;
OleDbCommand onlineConnection;
OleDbDataAdapter theDataAdapter;
// fill the "DataSet" each table in the set is a worksheet in the Excel file
foreach (DataRow dr in spreadSheetData.Rows) {
sheetName = dr["TABLE_NAME"].ToString();
sheetName = sheetName.Replace("'", "");
if (sheetName.EndsWith("$")) {
onlineConnection = new OleDbCommand("SELECT * FROM [" + sheetName + "]", myConnection);
theDataAdapter = new OleDbDataAdapter(onlineConnection);
dt = new DataTable();
dt.TableName = sheetName;
theDataAdapter.Fill(dt);
ds.Tables.Add(dt);
}
}
myConnection.Close();
scheduleGridView.DataSource = ds.Tables[0];
setLabel();
}
}
private void setLabel() {
label1.Text = "Showing worksheet " + sheetIndex + " Named: " + ds.Tables[sheetIndex].TableName + " out of a total of " + ds.Tables.Count + " worksheets";
}
private void btnNextSheet_Click(object sender, EventArgs e) {
if (sheetIndex == ds.Tables.Count - 1)
sheetIndex = 0;
else
sheetIndex++;
scheduleGridView.DataSource = ds.Tables[sheetIndex];
setLabel();
}

I solved it. Well there was a workaround. I used the Excel Data Reader found in this thread: How to Convert DataSet to DataTable
Which led me to https://github.com/ExcelDataReader/ExcelDataReader
^ The readme was fantastic, just went to solution explorer, right click on references, manage NuGet Packages, select browse in the new box, enter ExcelDataReader, then in the .cs file be sure to include, "using Excel;" at the top, the code mentioned in the first link was essentially enough, but here's my exact code for those wondering.
var frmDialog = new System.Windows.Forms.OpenFileDialog();
if (frmDialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
/*string strFileName = frmDialog.FileName;
//System.IO.FileInfo spreadSheetFile = new System.IO.FileInfo(strFileName);
System.IO.StreamReader reader = new System.IO.StreamReader(strFileName);
*/
string strFileName = frmDialog.FileName;
FileStream stream = File.Open(strFileName, FileMode.Open, FileAccess.Read);
//1. Reading from a binary Excel file ('97-2003 format; *.xls)
IExcelDataReader excelReader = ExcelReaderFactory.CreateBinaryReader(stream);
//...
//2. Reading from a OpenXml Excel file (2007 format; *.xlsx)
//IExcelDataReader excelReader = ExcelReaderFactory.CreateOpenXmlReader(stream);
//...
//3. DataSet - The result of each spreadsheet will be created in the result.Tables
//DataSet result = excelReader.AsDataSet();
//...
//4. DataSet - Create column names from first row
excelReader.IsFirstRowAsColumnNames = true;
DataSet result = excelReader.AsDataSet();
DataTable data = result.Tables[0];
//5. Data Reader methods
while (excelReader.Read())
{
//excelReader.GetInt32(0);
}
scheduleGridView.DataSource = data;
excelReader.Close();

Convert excel file (xls or xlsx) to csv file

I need this code C# working for files excel 2003 and 2007 version.
I can't get this C# code working to convert excel file (xls) on csv file.
If try with excel file extension xlsx it's all ok but if try with extension xls I have error in this line:
result.Tables[0].TableName.ToString();
My code below, what's wrong?
code-behind
FileUploadControl.SaveAs(Server.MapPath("/public/") + filename);
System.IO.FileStream stream = File.Open(filePath, FileMode.Open, FileAccess.Read);
Excel.IExcelDataReader excelReader = Excel.ExcelReaderFactory.CreateOpenXmlReader(stream);
DataSet result = excelReader.AsDataSet();
excelReader.Close();
result.Tables[0].TableName.ToString();
string csvData = "";
int row_no = 0;
int ind = 0;
while (row_no < result.Tables[ind].Rows.Count)
{
for (int i = 0; i < result.Tables[ind].Columns.Count; i++)
{
csvData += result.Tables[ind].Rows[row_no][i].ToString() + ",";
}
row_no++;
csvData += "\n";
}
keys = GetUniqueKey(8).ToUpper();
output = System.Web.HttpContext.Current.Server.MapPath("/public/target_" + keys.ToString() + ".csv");
StreamWriter csv = new StreamWriter(#output, false);
csv.Write(csvData);
csv.Close();

Excel can be of two types:
Binary - Excel 2003 and older - xls
Zip - based on Open Office XML standards - Excel 2007 onwards - xlsx
You should try to use following for older excel format files:
ExcelReaderFactory.CreateBinaryReader(stream);

Use any Xls to Xslx conversation tool. You can try Aspose libraries. I think it's licensed but you can try trail version.
You can do all other conversions as well using these libraries.

Here's how I do it - OLEDB - get the first sheet name, and remove all empty rows. Replace //whatever you need to do with your logic.
//Your Method signature
{
//create connection string
var connStr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path +
";Extended Properties='Excel 12.0;HDR=Yes;IMEX=1'";
//process
using (var conn = new OleDbConnection(connStr))
{
conn.Open();
//programatically get the first sheet, whatever it is named.
var sheetName = GetSheetNames(conn)[0].SheetNameOf;
var adapter = new OleDbDataAdapter(String.Format("SELECT * FROM [{0}]", sheetName), connStr);
var ds = new DataSet();
adapter.Fill(ds, "anyNameHere");
var data = ds.Tables["anyNameHere"];
//copy and remove blank lines
var resData = data.Clone();
var filteredData = data.Rows.Cast<DataRow>().Where(
row => !row.ItemArray.All(
field => field is DBNull ||
field == null ||
(String.IsNullOrEmpty(field.ToString().Trim())))
);
filteredData.CopyToDataTable(resData, LoadOption.OverwriteChanges);
var newData = resData.AsEnumerable();
//whatever you need to do
}
public List<SheetName> GetSheetNames(OleDbConnection conn)
{
if (conn.State != ConnectionState.Open)
{
conn.Open();
}
DataTable excelSchema = conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
var sheetNames = (from DataRow row in excelSchema.Rows
where !row["TABLE_NAME"].ToString().Contains("FilterDatabase")
select new SheetName { SheetNameOf = row["TABLE_NAME"].ToString() }
).ToList();
conn.Close();
return sheetNames;
}

You can use Aspose.Cells to convert excel file like xls or xlsx into csv format with the following simple code.
string filePath = #"F:\Downloads\source.xlsx";
Workbook workbook = new Workbook(filePath);
workbook.Save("output.csv", SaveFormat.CSV);
Note: I am working as developer evangelist at Aspose.

OleDB, Misses the first character of data

I have a CSV Reading code for ASP.NET application I maintain. This ASP.NET website is running fine from 3 yrs now, and CSV reading code that use Ole.JetDB.4.0 is doing its work fine, except that once in a while some CSV with more than 4K-5K records create a problem. Usually the problem is that a record at random position [random row] miss the first character of it.
CSV File is just bunch of name and addresses per row, and they are in ASNI Format. CSV is comma seperate, no data have "comma" in data and now enclosing of field in Single or Double quote. Also, it doesn't happen often, We use the same code for say 70K record upload they works fine, but some time say in 3 yrs about 3-4 files have this problem only, we upload about one file daily.
For those who need what I did
using (System.Data.OleDb.OleDbConnection conn = new System.Data.OleDb.OleDbConnection
("Provider=Microsoft.Jet.OLEDB.4.0;Extended Properties='text;HDR=Yes;FMT=Delimited';Data Source=" + HttpContext.Current.Server.MapPath("/System/SaleList/"))
{
string sql_select = "select * from [" + this.FileName + "]";
System.Data.OleDb.OleDbDataAdapter da = new System.Data.OleDb.OleDbDataAdapter();
da.SelectCommand = new System.Data.OleDb.OleDbCommand(sql_select, conn);
DataSet ds = new DataSet();
// Read the First line of File to know the header
string[] lines = System.IO.File.ReadAllLines(HttpContext.Current.Server.MapPath("/System/SaleList/") + FileName);
string header = "";
if (lines.Length > 0)
header = lines[0];
string[] headers = header.Split(',');
CreateSchema(headers, FileName);
da.Fill(ds, "ListData");
DataTable dt = ds.Tables["ListData"];
}
And this code is working fine except the mention thing. I cut some unrelated part so, might not work by copy paste.
EDIT: More information
I try to use ODBC with Microsoft Text Driver, then I use ACE Driver with OleDB. the result is same with all three drive.
If I swap the problem record, with the preceding Row those rows are read quite well, until the next problem row [if more than one row is having problem in original file], if those are only problem row it works fine.
So from above it looks like that something is there that distract character counter, but how I can ensure it working smooth is still a quiz.
EDIT 2: I have submitted it as bug to Microsoft here : https://connect.microsoft.com/VisualStudio/feedback/details/811869/oledb-ace-driver-12-jet-4-0-or-odbc-text-driver-all-fail-to-read-data-properly-from-csv-text-file

I would suggest you examine a problem file with a hex editor - inspect the line that causes the problem and the line immediately preceding it.
In particular look at the line terminators (CR/LF? CR only? LF only?) and look for any non-printable characters.

Try using ACE Driver instead of JET (it's available on x86 and x64 servers, JET is only x86!)
using (System.Data.OleDb.OleDbConnection conn
= new System.Data.OleDb.OleDbConnection
("Provider=Microsoft.ACE.OLEDB.12.0;Extended Properties="Excel 12.0 Xml;HDR=YES";
Data Source=" + HttpContext.Current.Server.MapPath("/System/SaleList/"))
{

I got the same OleDB, Missing characters of data problem, see here:
The characters go missing because the Microsoft.Jet.OLEDB.4.0 driver
tries to guess the column datatype. In my case its was treating the
data as hexadecimal not alphanumeric.
Problematic oledbProviderString:
oledbProviderString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=\"
{0}\";Extended Properties=\"Text;HDR=No;FMT=Delimited\"";
To fix the problem I added TypeGuessRows=0
oledbProviderString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=\"
{0}\";Extended Properties=\"Text;HDR=No;FMT=Delimited;TypeGuessRows=0\"";
Repro:
Create a Book1.csv file with this content:
KU88,G6,CC
KU88,F7,CC
Step through this code as pictured above.
private void button1_Click(object sender, EventArgs e)
{
string folder = #"G:\Developers\Folder";
ReproProblem(folder);
}
static string oledbProviderString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=\"{0}\";Extended Properties=\"Text;HDR=No;FMT=Delimited\"";
private void ReproProblem(string folderPath)
{
using (OleDbConnection oledbConnection = new OleDbConnection(string.Format(oledbProviderString, folderPath)))
{
string sqlStatement = "Select * from [Book1.csv]";
//open the connection
oledbConnection.Open();
//Create an OleDbDataAdapter for our connection
OleDbDataAdapter adapter = new OleDbDataAdapter(sqlStatement, oledbConnection);
//Create a DataTable and fill it with data
DataTable table = new DataTable();
adapter.Fill(table);
//close the connection
oledbConnection.Close();
}
}

why dont u just use this:
using (System.Data.OleDb.OleDbConnection conn = new System.Data.OleDb.OleDbConnection
("Provider=Microsoft.Jet.OLEDB.4.0;Extended Properties='text;HDR=Yes;FMT=Delimited';Data Source=" + HttpContext.Current.Server.MapPath("/System/SaleList/"))
{
string sql_select = "select * from [" + this.FileName + "]";
System.Data.OleDb.OleDbDataAdapter da = new System.Data.OleDb.OleDbDataAdapter();
da.SelectCommand = new System.Data.OleDb.OleDbCommand(sql_select, conn);
DataSet ds = new DataSet();
// Read the First line of File to know the header
string[] lines = System.IO.File.ReadAllLines(HttpContext.Current.Server.MapPath("/System/SaleList/") + FileName);
DataTable mdt=new DataTable("ListData");
for (int i = 1; i < lines.Length; i++)
{
string[] sep=lines[i].Split(',');
foreach (var item in sep)
{
mdt.Rows.Add(sep);
}
}
string header = "";
if (lines.Length > 0)
header = lines[0];
string[] headers = header.Split(',');
ds.Tables.Add(mdt);
CreateSchema(headers, FileName);
da.Fill(ds, "ListData");
DataTable dt = mdt;}
i didnt debugged it. i hope there is no problem but if there is im here for you.
thank you very much

C# VS2005 Import .CSV File into SQL Database

I am trying to import a .csv file into my database. I am able to import an excel worksheet into my database, however due to different file format as .csv as from .xls, I need to make an import function specially for .csv.
Below is my code:
protected void Button1_Click(object sender, EventArgs e)
{
if (FileUpload1.HasFile)
{
// Get the name of the Excel spreadsheet to upload.
string strFileName = Server.HtmlEncode(FileUpload1.FileName);
// Get the extension of the Excel spreadsheet.
string strExtension = Path.GetExtension(strFileName);
// Validate the file extension.
if (strExtension != ".xls" && strExtension != ".xlsx" && strExtension != ".csv" && strExtension != ".csv")
{
Response.Write("<script>alert('Failed to import DEM Conflicting Role Datasheet. Cause: Invalid Excel file.');</script>");
return;
}
// Generate the file name to save.
string strUploadFileName = #"C:\Documents and Settings\rhlim\My Documents\Visual Studio 2005\WebSites\SoD\UploadFiles\" + DateTime.Now.ToString("yyyyMMddHHmmss") + strExtension;
// Save the Excel spreadsheet on server.
FileUpload1.SaveAs(strUploadFileName);
// Create Connection to Excel Workbook
string connStr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + strUploadFileName + ";Extended Properties=Text;";
using (OleDbConnection ExcelConnection = new OleDbConnection(connStr)){
OleDbCommand ExcelCommand = new OleDbCommand("SELECT [columns] FROM +userrolelist", ExcelConnection);
OleDbDataAdapter ExcelAdapter = new OleDbDataAdapter(ExcelCommand);
ExcelConnection.Open();
using (DbDataReader dr = ExcelCommand.ExecuteReader())
{
// SQL Server Connection String
string sqlConnectionString = "Data Source=<IP>;Initial Catalog=<DB>;User ID=<userid>;Password=<password>";
// Bulk Copy to SQL Server
using (SqlBulkCopy bulkCopy =
new SqlBulkCopy(sqlConnectionString))
{
bulkCopy.DestinationTableName = "DEMUserRoles";
bulkCopy.WriteToServer(dr);
Response.Write("<script>alert('DEM User Data imported');</script>");
}
}
}
}
else Response.Write("<script>alert('Failed to import DEM User Roles Data. Cause: No file found.');</script>");
}
The file has been successfully saved, but the error says that the path for the file is not valid, even though the file has been successfully saved as .csv, therefore I am not able to continue with the process of importing the data into my database.
Below are the screenshots of my error:
In conclusion I am having the error that the file path which the csv file is saved is not valid, although the csv file is successfully saved. Need some help from experienced. Thank You

If you're reading a CSV file, your connection string should specify the directory containing your CSV file.
string connStr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" +
Path.GetDirectoryName(strUploadFileName);
You then use the filename in your SELECT statement:
"SELECT * FROM [" + Path.GetFileName(strUploadFileName) + "]"

I think you have this problem because you use "/" instead of "\"
Try to modify the path C:\.....

You need to use the backward slashes(\) on the file path.
string strUploadFileName = #"C:\Documents and Settings\rhlim\My Documents\Visual Studio 2005\WebSites\SoD\UploadFiles\" + DateTime.Now.ToString("yyyyMMddHHmmss") + strExtension;
EDIT 1: I believe FileUpload1.SaveAs converts the / to \ internally to identify the correct location.
EDIT 2: Its the problem with your connectionstring, even though you are using .csv format, you need to set Excel 8.0 or Excel 12.0 Xml as the Extended Properties
Here is the sample:
string connStr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + strUploadFileName + ";Extended Properties=Excel 12.0 Xml;";
For other types, check the code of OLEDB section of my article.

To avoid the connection open you can use like
// Read the CSV file name & file path
// I am usisg here Kendo UI Uploader
string path = "";
string filenamee = "";
if (files != null)
{
foreach (var file in files)
{
var fileName = Path.GetFileName(file.FileName);
path = Path.GetFullPath(file.FileName);
filenamee = fileName;
}
// Read the CSV file data
StreamReader sr = new StreamReader(path);
string line = sr.ReadLine();
string[] value = line.Split(',');
DataTable dt = new DataTable();
DataRow row;
foreach (string dc in value)
{
dt.Columns.Add(new DataColumn(dc));
}
while (!sr.EndOfStream)
{
value = sr.ReadLine().Split(',');
if (value.Length == dt.Columns.Count)
{
row = dt.NewRow();
row.ItemArray = value;
dt.Rows.Add(row);
}
}
For more help you can also See This Link