Question

I’m using the following code to import a simple excel spreadsheet into a dataset via an ole db connection. I’m seeing different behavior when reading dates from the spreadsheet depending on whether the spreadsheet is opened by another process or not.

The behavior can easily be re-produced. Create an xlsx file with a header row and one row of data with a date field. Try 1/1/2011. Leave the spreadsheet open and run the following code and inspect the xml output. You will see the value 40544 where 1/1/2011 should have been, if you close the spreadsheet and run the same code you will actually see 1/1/2011 in the xml output. Any ideas or suggestions on how to get consistent behavior?

var fileName = @"C:\Test.xlsx";
var connectionString = String.Format(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=""Excel 12.0;HDR=NO;IMEX=1;""", fileName);

var adapter = new OleDbDataAdapter("SELECT * FROM [Sheet1$]", connectionString);
var ds = new DataSet();

adapter.Fill(ds);

ds.WriteXml(@"c:\test.xml");

Answer 1

Create an xlsx file with a header row

Check.

var connectionString = String.Format(@”Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=””Excel 12.0;HDR=NO;IMEX=1;”””, fileName);

Huh? 🙂

Change HDR (header) to Yes and I think you’ll see it fixes the problem.