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Reading an Excel into a Datatable with C# incorrectly formats numbers

Please do let me know if this is a duplicate; I couldn't find an actual answer..
Found this, related one,
Scientific notation when importing from Excel in .Net
But it is several years old
So I am reading an Excel file, into a DataTable with C#.
My code is as follows:
string conStr = string.Format("Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=\"Excel 12.0;HDR=NO;IMEX=1;\"", filePath);
System.Data.DataTable fileData = new System.Data.DataTable();
using (OleDbConnection connection = new OleDbConnection(conStr))
{
connection.Open();
if (string.IsNullOrEmpty(sheetName))
{
sheetName = connection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null).Rows[0]["TABLE_NAME"].ToString();
}
string selectCmd = string.Format(sqlSelect, sheetName);
using (OleDbCommand command = new OleDbCommand(selectCmd, connection))
using (OleDbDataAdapter adapter = new OleDbDataAdapter(command))
{
adapter.Fill(fileData);
}
}
So this reads everything in and populates my DataTable
Further through the code I perform validations on some of the content. I'm using RegEx for this.
However, I am running into an issue, where the numbers are being formatted to a scientific notation, or exponential format.
For example, I have 0.000083 and it is being read in as 8.3e-005
So - how can I read in the excel file, and keep the original 0.000083 ?
I'm good with bringing everything in as a string if needed... I've played with the extended properties, but nothing seems to affect how the data is read.
Looking for a solution that negates me having to add each individual cell to the datatable
UPDATE
The other thing I can do, in the meantime, Is convert a scientific-notation to a decimal, and then check that. Though ideally I would like to just bring in without the notation in the first place.

Search Excel sheet from ASP.NET C#

UPDATE:
I have found that this code works! it searches the Excel sheet and only outputs the data I need.
But can anyone explain to me why this works? how does it know that the first line in the spreadsheet is the "index"??
//Coneection String by default empty
string ConStr = "";
//connection string for that file which extantion is .xlsx
ConStr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + "C:\\TestExcel.xlsx" + ";Extended Properties='Excel 12.0 XML;HDR=YES;';";
//making query
string query = "SELECT * FROM [lol$] where ID='i2200'";
//Providing connection
OleDbConnection conn = new OleDbConnection(ConStr);
//checking that connection state is closed or not if closed the
//open the connection
if (conn.State == ConnectionState.Closed)
{
conn.Open();
}
//create command object
OleDbCommand cmd = new OleDbCommand(query, conn);
// create a data adapter and get the data into dataadapter
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
DataSet ds = new DataSet();
//fill the Excel data to data set
da.Fill(ds);
foreach (DataRow row in ds.Tables[0].Rows)
{
lblud.Text = "" + row["Hylde"];
}
OLD
I have been trying to do this for several hours now but no matter what i try, I don't end up with the result i want.
So now im "starting from scratch" again. See if I have approached this incorretly.
Question:
I wan't to create a ASPX website that can search my excel sheet for specific data.
Something like Select * from [Sheet1$] where Column A = i2200
then display only Column B and C from that specific row into a Label / two labels.
See picture here: http://itguruen.dk/EXCEL.png
Does anyone have a simple way of doing this?
Thanks in advance!
Jasper

Have you thought about importing the Excel Spreadsheet into a DataTable, and then analyse that DataTable to populate your labels? You can perform SQL queries on DataTables, so you'll be able to extract the exact data you require quite easily (the hardest part will be importing the Excel Spreadsheet into the DataTable).
There's a very detailed report on this process here: http://www.aspsnippets.com/Articles/Read-and-Import-Excel-File-into-DataSet-or-DataTable-using-C-and-VBNet-in-ASPNet.aspx

Update the post so you can see the solution.
Allthough I dont really know why this works??

Getting Oledb exception when updating column in excel

I am getting the following error "No value given for one or more required parameters." On the ExceuteNonQuery() line of the below code.
System.Data.OleDb.OleDbConnection finalConnection;
System.Data.OleDb.OleDbCommand myCommand = new System.Data.OleDb.OleDbCommand();
string sql = null;
finalConnection = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0; Data Source ='c:\\temp\\test.xlsx'; Extended Properties ='Excel 12.0 Xml;HDR=NO';");
finalConnection.Open();
myCommand.Connection = finalConnection;
foreach (VinObject v in VinList)
{
sql = "Update [Sheet1$] set O = ? where S = ?;";
myCommand.Parameters.Add(new OleDbParameter("#amt", v.CostNewAmt));
myCommand.Parameters.Add(new OleDbParameter("#vin", v.VIN));
myCommand.CommandText = sql;
myCommand.ExecuteNonQuery();
}
finalConnection.Close();
I have also tried using a separate command each time, same error.
foreach (VinObject v in VinList)
{
using (OleDbConnection con = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0; Data Source ='c:\\temp\\test.xlsx'; Extended Properties ='Excel 12.0 Xml;HDR=No';"))
{
con.Open();
string query = #"UPDATE [Sheet1$] SET O = ? WHERE S = ?";
OleDbCommand cmd = new OleDbCommand(query, con);
cmd.Parameters.AddWithValue("#param1", v.CostNewAmt);
cmd.Parameters.AddWithValue("#param2", v.VIN);
cmd.ExecuteNonQuery();
con.Close();
}
}
I am able to modify that into an insert and insert into a new excel spreadsheet, but for the life of me cannot get this update to work. Any idea what I am doing wrong? Thanks for the help.

You're getting the error because Excel doesn't recognize the column letter aliases "O" and "S". It needs the actual column "name", which is the value of the cell in the first populated row. If there is not a valid value in that cell, or you have specified HDR=NO in your connection string, the columns will be named F1, F2...Fn. If you're not sure what the inferred column names are, examine the names using OleDbConnection.GetSchema(String,String[]) or OleDbDataReader.GetName(Int32).
Since you have specified HDR=NO in your connection string, your correct SQL will likely be
"Update [Sheet1$] set F15 = ? where F19 = ?;"
For future reference, check out:
How to query and display excel data by using ASP.NET, ADO.NET, and Visual C# .NET
How to transfer data to an Excel workbook by using Visual C# 2005 or Visual C# .NET
How To Use ADO.NET to Retrieve and Modify Records in an Excel Workbook With Visual Basic .NET. (Still lots of helpful info even if you are using C#)

Reading excel file in c#.net cell by cell

I'm new to c#.net
I have excel sheet and I want to import into database.
I want to read it cell by cell and want to insert value in database.
this.openFileDialog1.FileName = "*.xls";
DialogResult dr = this.openFileDialog1.ShowDialog();
if (dr == System.Windows.Forms.DialogResult.OK)
{
string path = openFileDialog1.FileName;
string connectionString = String.Format(#"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties=""Excel 8.0;HDR=no;IMEX=1;""", openFileDialog1.FileName);
string query = String.Format("select * from [{0}$]", "Sheet3");
OleDbDataAdapter dataAdapter = new OleDbDataAdapter(query, connectionString);
DataSet dataSet = new DataSet();
dataAdapter.Fill(dataSet);
dataGridView1.DataSource = dataSet.Tables[0];

I assume that after you execute the code in your question, you can see the values within dataGridView1.
The actual reading from the excel sheet is done when calling dataAdapter.Fill. So, in your case, reading the cells comes down to indexing columns and rows in dataSet.Tables[0].
For example:
for (int row = 0; row < dataSet.Tables[0].Rows.Count; row++)
{
DataRow r = dataSet.Tables[0].Rows[row];
}
Accessing the cells in row r is trivial (like the sample above, just for cell).
EDIT
I forgot to describe the "insert the values into a database" part. I presume that the database is SQL Server (may be Express edition, too).
First: create a database connection. Instead of manually composing the connection string, use the SqlConnectionStringBuilder:
SqlConnectionStringBuilder csb = new SqlConnectionStringBuilder();
csb.DataSource = <your server instance, e.g. "localhost\sqlexpress">;
csb.InitialCatalog = <name of your database>;
csb.IntegratedSecurity = <true if you use integrated security, false otherwise>;
if (!csb.IntegratedSecurity)
{
csb.UserId = <User name>;
csb.Password = <Password>;
}
Then, create and open a new SqlConnection with the connection string:
using (SqlConnection conn = new SqlConnection(csb.ConnectionString))
{
conn.Open();
Iterate over all the values you want to insert and execute a respective insert command:
for (...)
{
SqlCommand cmd = new SqlCommand("INSERT INTO ... VALUES (#param1, ..., #paramn)", conn);
cmd.Parameters.AddWithValue("#param1", value1);
...
cmd.Parameters.AddWithValue("#paramn", valuen);
cmd.ExecuteNonQuery();
}
This closes the connection, as the using block ends:
}
And there you go. Alternatively, you could use a data adapter with a special insert-command. Then, inserting the values would come down to a one-liner, however, your database table must have the same structure as the Excel-sheet (respectively: as the data table you obtained in the code you posted.

Check out NPOI
http://npoi.codeplex.com/
It's the .NET version of Apache's POI Excel implementation. It'll easily do what you need it to do, and will help avoid some of the problems ( i.e. local copy of Excel, or worse, copy of Excel on the server ) that you'll face when using the Jet provider.

Writing to a blank excel sheet with ADO.NET

I am trying to use ADO.NET to connect to and write to an excel file. I have created a blank file with the default excel sheets (I have also tried with a custom sheet.)
For some reason I am unable to write a full row of data to the sheet. If I create a new sheet it works fine, however then I have too many sheets and I am unable to delete any sheets.
Is there something special you need to do to write a row of data to a blank sheet?
I try to do:
path= the path including my file.
connString = String.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties=\"Excel 8.0;HDR=NO;\"", Server.MapPath(path));
dbCmd.CommandText = "Update [Sheet1$] Set F1 = 'Col1', F2 = 'Col2', F3 = 'Col3', F4 = 'Col4'";
dbCmd.ExecuteNonQuery();

Here's an example of creating a brand new spreadsheet, creating a sheet (Sheet1) and then inserting a row into that. Most of this example was based on a blog entry from David Hayden (great blog entry for this task, btw!!).
Also, you should check out this Microsoft KB article for reading/writing to Excel from ADO.NET -- it really goes into a lot of detail.
//Most of this code was from David Hayden's blog:
// http://www.davidhayden.com/blog/dave/archive/2006/05/26/2973.aspx
static void Main(string[] args)
{
string connectionString = #"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Temp\TestSO1.xls;Extended Properties=""Excel 8.0;HDR=NO;""";
DbProviderFactory factory =
DbProviderFactories.GetFactory("System.Data.OleDb");
using (DbConnection connection = factory.CreateConnection())
{
connection.ConnectionString = connectionString;
using (DbCommand command = connection.CreateCommand())
{
connection.Open(); //open the connection
//use the '$' notation after the sheet name to indicate that this is
// an existing sheet and not to actually create it. This basically defines
// the metadata for the insert statements that will follow.
// If the '$' notation is removed, then a new sheet is created named 'Sheet1'.
command.CommandText = "CREATE TABLE [Sheet1$] (F1 number, F2 char(255), F3 char(128))";
command.ExecuteNonQuery();
//now we insert the values into the existing sheet...no new sheet is added.
command.CommandText = "INSERT INTO [Sheet1$] (F1, F2, F3) VALUES(4,\"Tampa\",\"Florida\")";
command.ExecuteNonQuery();
//insert another row into the sheet...
command.CommandText = "INSERT INTO [Sheet1$] (F1, F2, F3) VALUES(5,\"Pittsburgh\",\"Pennsylvania\")";
command.ExecuteNonQuery();
}
}
}
The only problem I found is that even though the connection string states not to use headers, you still have to define column names for your sheet, and ADO.NET inserts a row when you create the sheet that has the row header names. I can't seem to find a way around that besides going in after I insert everything and removing the first row. Not very elegant.
Hope this helps!! Let me know if you have other questions.