Unknown Exception

Administrator

Hi ! When i run me program on my Windows XP Computer which is also fast enough it works great. But when i try to run it on the ME Machine which is slower I get the following Exception in the Main() Funktion: "Object reference not set to an instance of an Object" My Main() Funktion looks like this: static void Main() { Application.Run(new MainWindows()); } Please anybody help ! Thanks, Nick

3 Replies

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Administrator23y ago
It is possible that it is because you delete the .mdb file and run your program that you get that problem. It is because you try to connect to that database, but it isn't there. So you got a variable which is normally (if you do not delete the mdb file) to the mdb file. This variable will be 'null'. So you got a nullpointer. If you are doing something with it, or try to close the database at the end of your program, you will get that exception: "Object reference not set to an instance of an Object" Because the variable will not point to your database. I think that your problem is something like that. So you have to control if you do not have a nullpointer. Something like if (dbmConnection != null) { ... } It is also possible that there are other variables refering to null because of that connection. So you have to check this out.
Administrator23y ago
hi ! well, i open an access database. it is possible that on the ME machine (it is not mine, i haven't seen it yet) where the problem occurs, are no access drivers installed or no ODBC. Because on the XP machine it worked, but when i delete the .mdb database file, i get this error message. is it necessary for the .NET framework to access .MDB files that there is something installed in the systemconfiguration ?
Administrator23y ago
Can you post some more code? Because I think that it will not be a problem with your main function, but with some variables in your program. Probably some variables initialized in your main form that you are using in other forms. I also had this problem in a program and I fixed it. Maybe some more information will help us with finding your problem.