saving and reading data into textboxes from sql database

Question

i have four textboxes,a button and some other comboboxes, the textboxes is meant for the studentid,department,faculty,and programme whereby if the user enter a studentid  and click the search button these othe textboxes will be filled up from the registeredstudent database but my problem is that whenever i enter a studentid and click the search button these textboxes will be filled and when i want to continue with other comboboxes ,when choosed a combobox the data are still there but choosing another combobox all the data in the textboxes will disappear.Another problem is that i have a metrogrid(from metro framework) where i see my saved inputs but whenever i click the search button with the textboxes filled but when i click on on textbox the data in it is shown in the metrogrid but clicking on another textbox all other filled data except the one shown in the metrogrid disappears. please i need help. This program is in c sharp windows form application not ASP.NET