Cannot read Registry Value - object reference not set to an instance of an object

Question

I am banging my head around a constant error "Object reference not set to an instance of an object" when reading the value of a registry key. please give me your suggestions of how to resolve.

string regkey = @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{A8EC0CC0-AD8D-4244-B080-424EDF7A7634}";
object thekey = Registry.LocalMachine.OpenSubKey(regkey).GetValue("DisplayName");
TraktorVersion = thekey.ToString();

where TraktorVersion is a string.

Could you show how "TraktorVersion" is defined prior to this reference? — Joshua Briefman, Jan 14 '17 at 22:33
Hi Joshua, it is defined in the same class as string TraktorVersion; — Blagovest, Jan 14 '17 at 22:42

score 0 · Answer 1 · answered Jan 14 '17 at 22:20

0

Are you sure that key exist in the registry? Check that thekey is not being set to null.

string regkey = @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{A8EC0CC0-AD8D-4244-B080-424EDF7A7634}";
object thekey = Registry.LocalMachine.OpenSubKey(regkey).GetValue("DisplayName");    
if(thekey!=null)    
   TraktorVersion = thekey.ToString();

answered Jan 14 '17 at 22:20

jbriggs

353
2
10

The key is copied and pasted from the registry and DisplayName value has data inside. I made a test with GetValueNames and only 3 values were returned. In the key there are around 10 values which confuses me even more. – Blagovest Jan 14 '17 at 22:32
You may need elevated rights to see the other values. Try right clicking on your app and run as administrator – jbriggs Jan 14 '17 at 22:42
2

Is your application 32-bit running on 64-bit workstation? Then some keys may not be available and you should look in Software\Wow6432Node regkey. – VitaliyK Jan 14 '17 at 22:42
Hi jbriggs, the put if statement if (thekey != null) { TraktorVersion = thekey.ToString(); System.Windows.MessageBox.Show(TraktorVersion); } , compiled and ran with admin rights. the message box didn't appear – Blagovest Jan 14 '17 at 22:50
That's because the key didn't exist or is isn't accessible. @VitaliyK could be right also. What are you using to view the registry? – jbriggs Jan 14 '17 at 23:20
on the command prompt you can run reg query "hklm\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall" /reg:32 If that shows the same 3 values then you know it's a 32bit vs 64bit thing – jbriggs Jan 14 '17 at 23:28

Cannot read Registry Value - object reference not set to an instance of an object

1 Answers1