Issue deleting a registry key

Question

I am trying to delete a registry key, so far I tried that code which seems to be normal :

        RegistryKey delete = Registry.CurrentUser.OpenSubKey("SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Image File Execution Options");
        delete.DeleteSubKeyTree("MyPaintApp");
        delete.Close();

But I get the ERROR :

Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object.

I googled my problem and searched stackoverflow and applied some solutions , but all seem to be using the same method I am using, so I'm fed up and I hope you can help me with that.

EDIT : SORRY I used CurrentUser instead of LocalMachine in my registryKey path , that was the problem.

Answer 1

The documentation for OpenSubKey states:

Return Value
Type: Microsoft.Win32.RegistryKey
The subkey requested, or null if the operation failed.

Thus opening the key seems to have failed. most likely because it doesn't exist:

If the specified subkey cannot be found, then null is returned.

On my Win7 comp, the Image File Execution Options subkey doesn't exist.

---

But even when you fix that part, it'll still fail. The overload of OpenSubKey you are using is documented as:

Retrieves a subkey as read-only.

So you should use OpenSubKey(path,true), like @lasseespeholt recommends.

http://msdn.microsoft.com/en-us/library/z9f66s0a.aspx

Answer 2

Please try using Registry.CurrentUser.DeleteSubKeyTree(fullSubKeyPath);.

Details here: RegistryKey.DeleteSubKeyTree Method (String).