The first thing to say is: probably, you are making a mistake by trying to "fix" the culture to any format - particularly if it is one which can be confused. People set the culture on their PC to what they are used to, and fixing it to something else may cause problems or even anger. So unless this is for a very, very good reason, then don't do it.
If it is for a good reason, then it's pretty simple to do: I assume that you are using a DateTime value here, as string based dates don't change format! :laugh:
All you have to do is stop using the default transformation. Without knowning exactly what you are doing to display it, it's difficult to be precise about what you need to do, ybut at somepoint you are using the default ToString implementation, either explicitly or implicitly via a string concatenation. Instead, specify exactly what format you want:
DateTime now = DateTime.Now;
string s = now.ToString("yyyy/MM/dd");
If the problem is that the dates in Access are being displayed in the local format, then changing the thread culture will not help - the Access instance will not share a common thread with your application because it is a separate Process, with it's own thread collection, so changing the culture will have no affect on it. And if you start mucking with the global culture you will
really annoy your users!
It may be possible to format the date output for specific data in Access itself, depending on what you are using to display the info.