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Overwrite Data in Excel file with OleDb C#?

is it possible to overwrite data in cells with OleDb in C# with a specific row range?
I only found adding data to first empty cells in specific column like
string sql = "Insert into [Tabelle1$] (testA, testB) values(6,7)";
If its not possible what assembly is fast for this task ....Microsoft.Office.Interop is horrible slow.
Thanks for any tip

Adding string to int32 column in datatable

I am pretty sure this is not possible but I will ask for clarification.
I am using ExcelLibrary in C# to convert a dataset into an Excel document. I recently had the requirement to add a string to the end of the excel document in every file. I simply added two new rows to the datatable (one empty and the second row displayed the string in the first cell).
I got a bug report today because in one particular excel document the first column displays the ID (something unusual in the system) and I get the error:
Input string was not in a correct format.Couldn't store <**mystring**> in id Column. Expected type is Int32.
I am pretty sure I cannot add my string to this column and I need to add it to a different column which is a nvarchar, but does anyone have any suggestions to resolve this problem?
edit: the code for anyone who may require it
DataRow dr = ds.Tables[0].NewRow();
ds.Tables[0].Rows.Add(dr);
DataRow dr2 = ds.Tables[0].NewRow();
dr2[0] = System.Configuration.ConfigurationManager.AppSettings["excelString"];
ds.Tables[0].Rows.Add(dr2);
The dataset I am working with is directly from a query in the database and the first column is an INT

OleDbConnection only finds cell value when workbook is also open in Excel

I have a program (actually SSIS script task, but I don't suppose that matters) that creates an OLE DB connection to an Excel workbook, and reads the cell values in each worksheet, storing them in a SQL Server table.
Each worksheet has several sections of rows, each section being for a separate product. The first two rows of each product section are a quarter row, and a year row. Here is a screen shot:
I use an OleDbDataReader with a "Select *" command to read the data in each sheet into a DataTable. I have a column called "YearQuarter" in my SQL database, where I store a concatenation of the year row value and the preceding quarter row value, with a hyphen between the two strings:
My code is like this:
OleDbConnection oleExcelConnection = new OleDbConnection(
"Provider=Microsoft.ACE.OLEDB.12.0;" +
"Data Source=" + strWkbkFilePath + ";" +
"Mode=Read;" +
"Extended Properties=\"Excel 8.0;HDR=No;IMEX=1\"");
oleExcelConnection.Open();
DataTable dtCurrSheet = new DataTable();
// Name of table is in strLoadTblNm.
OleDbCommand oleExcelCommand;
OleDbDataReader oleExcelReader;
oleExcelCommand = excel_conn.CreateCommand();
oleExcelCommand.CommandText = "Select * From [" + strLoadTblNm + "]";
oleExcelCommand.CommandType = CommandType.Text;
oleExcelReader = oleExcelCommand.ExecuteReader();
// Load worksheet into data table
dtSheet.Load(oleExcelReader);
oleExcelReader.Close();
Looking at the output data, I noticed that I was getting inconsistent results. Some rows would have a YearQuarter column value that would have only the Year row value in them, while others would have the cell values from both rows. For example, I'd have "2009 - Year End" followed by just "2010", with no " - 1st Qtr." appended to it.
This is because that quarter cell valued is never loaded into the data reader, as the Dataset Visualizer shows:
Notice also that, in the Dataset, the column that is missing the Quarter cell value also has other numeric values missing their formatting (no commas).
If I save the file as a .csv, all cell values are preserved.
However, I noticed that it wasn't consistent. Sometimes I'd run my package and the same row would now have the full value. So, in the above example, I'd get "2010 - 1st Qtr."
I finally realized that it was working as expected only if I happened to have the workbook open in Excel at the same time that the program was running!
Why would this make a difference? Could it be that there is a macro or something in the workbook that is executed by Excel, but not when the workbook is accessed only via an OLE DB connection? Would the fact that it had been executed in Excel then affect the data obtained by OLE DB? If that's the case, how do I get around this? The spreadsheets are provided to me. So I can't modify them.

I think you're having issues with the auto-formatting thing Excel tries to apply. With an OLEDB connection, I can't see how having the sheet open fixes your problem (obviously very strange).
Try Adding IMEX = 1 to your connection options to treat the entire sheet as text to see if this is your issue. Pulled from OLEDB connection does not read data from excel sheet Also another good post from an external site: Tips for reading Excel spreadsheets using ADO.NET
Also, you're pulling data from an excel sheet and writing it to another excel sheet... Same workbook? I have a couple more ideas for ya though depending on your situation.

This bug turns out to be a "feature", and it should come with a big warning sign.
This article (thanks, #vb4all) explains that "ADO.NET scans the first 8 rows of data, and based on that, guesses the datatype for each column. Then it attempts to coerce all data from that column to that datatype, returning NULL whenever the coercion fails!"
In other words, it is treating the worksheet as a relation table, in which all values in a given column are of the same type. Of course, worksheet data is not bound by this restriction.
This behavior can be gotten around by setting IMEX=1 in the connection string options and then modifying these registry settings:
Hkey_Local_Machine/Software/Microsoft/Jet/4.0/Engines/Excel/ImportMixedTypes
Hkey_Local_Machine/Software/Microsoft/Jet/4.0/Engines/Excel/Typ
(Note: registry keys vary depending on 32 vs. 64 bit. E.g., for 64-bit, the first one would be HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Jet\4.0\Engines\Jet 4.0).
I think this was a very risky design, inviting data transfer errors that could easily go unnoticed.

Import Excel to DataTable string's are empty

To import excel to datatable, I am using the simple code:
string connectionString = string.Format("Provider=Microsoft.ACE.OLEDB.12.0; data source={0}; Extended Properties=Excel 12.0;", physicalFolder + FileUpload1.FileName);
OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT * FROM [Sheet1$]", connectionString);
DataSet ds = new DataSet();
When in one of the rows of excel, if my row looks like below
strings are ommited and my data set looks like this
However if I add some strings and if my upload looks like this:
Then my dataset looks like it does not omit the strings:

Try to change your oledbconnection string as following format:
Code Snippet
OleDbConnection con = new OleDbConnection(
#"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\book1.xls;Extended Properties='Excel 8.0;HDR=Yes;IMEX=1'");
Note: "IMEX=1;" tells the driver to always read "intermixed" (numbers, dates, strings etc) data columns as text. Note that this option might affect excel sheet write access negative.

MD.Unicorn's answer is not 100% correct. Your OLEDB provider uses a settings named TypeGuessRows to determine how many rows are read to decide the data type of a column. Unfortunately this setting cannot be specified in the connection string and must be changed in the system registry. See this question for more details.

This is because the provider decides on the type of the column from first row of the column (the row after the header row). When first row contains a number, the type of column is double or another number type, so it cannot contain string values.
I tried every possible way (setting the table structure beforehand, using a DataReader, changing the format of the cell, ...) and they all failed. It seem to be the problem with Microsoft.Jet.OLEDB provider. I highly recomment you to use a third party excel reading library. There are plenty of open source libraries available.
If your file is a Excel 2007 (.xlsx) file, I highly recommend using EPPluse. It is also available as a NuGet package.
Otherwise, you can take a look at this answer to find a few more libraries.

use IMEX=1 in connection string. hope it will resolve this issue..

How to get data of a column of a sheet by c#

I have wrote a winform application that can open and read from a sheet of an excel file.I have used OleDbDataAdapter to read data and then set the data to a datatable. but my problem is that in this datatable the first row of data is used as the name of the columns however i want to use the base names that excel defines for each column (I mean "A B C ... AA AB ..." and so on).

Take a look at this answer Importing Excel data into C# without first row becoming column names?
It seems you need to change the connection string Extended Properties=\"Excel 8.0;HDR=No;IMEX=1;\" and make sure HDR=No is set.