Read Excel documents with C#

add a new reference to the assembly:
Microsoft.Office.Interop.Excel

Now you have a new namespace: Microsoft.Office.Interop.Excel (for short I will call it "Excel")

Create a new application object
Excel.Application appExcel = new Excel.ApplicationClass();

Now a new excel is running in the background.
You can open new worksheets with:
Excel.Worksheets ws = appExcel.Worksheet;
ws .open().

You can find all the documentations here:
http://msdn.microsoft.com/de-de/library/microsoft.office.interop.excel%28en-us%29.aspx


VERY IMPORTANT:
These classes are COM classes, therefore you *MUST* release them before quitting (using quit() method) the excel application.
If you don't release all the object, the excel.exe will simply won't quit.

To do that you need to use:
Marshal.ReleaseComObject()
(http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.marshal.releasecomobject.aspx)

As an example,
lets say that you're using appExcel and ws that I wrote above, than you will have to:
appExcel.quit();
Marshal.ReleaseComObject(appExcel);
Marshal.ReleaseComObject(ws);

Good Luck!

There is not  another way to do this without open Excel?

ok thanks... i will check it out ;)