Fix some code in a c# windows application

A c# visual studio 2015 windows application need to be fixed .The application asks the user to enter data In different cultures , and when the user choose the culture ,the language of the application changes changes and the dates as [login to view URL] clicking on Save Data , the application saves the data to a text file ,and when clicking on Get Data the app restores the data from the file .But the problem is , if clicked Get Data after changing the culture , the app restores the date in the format of the chosen culture. What required is , when clicking on Get Data after changing the culture , the format of the date should stay the same as the first chosen culture