I am using OleDB Ace 12 to read an Excel (xslx) sheet containing a column with decimal values. When I open the Excel sheet on my PC a decimal value is correctly formatted as
I think you will get it US format only. You can convert it in code:
string strFloatingNumber = "24.45"; //a floating point number in English notation
double output = 0.0; //output double number which will hold the value
double.TryParse(strFloatingNumber, out output); //convert without exception - assuming no error
MessageBox.Show(output.ToString("N2", CultureInfo.CreateSpecificCulture("nl-NL")));