[RESOLVED] Get the value of a dword from the registry

[chris1990]

I am unable to get a value from the registry, every time i run my code it returns a value of 'NoAutoRebootWithLoggedOnUser', even though the value should be 1.

What have i done wrong?

Thanks Chris1990,

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
         ''CheckStatus()

        Dim readValue As String
        readValue = My.Computer.Registry.LocalMachine.GetValue _
    ("SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU", "NoAutoRebootWithLoggedOnUser", Nothing)
        MsgBox("The value is " & readValue)
    End Sub

[Grimfort]

readValue should be an object that is returned not always a string, see this example.

This part especially:

Case RegistryValueKind.DWord
Console.WriteLine("Value = " + Convert.ToString(CType(o,Int32)))

[Sitten Spynne]

It's a matter of not paying attention to your code.

My.Computer.LocalMachine returns a RegistryKey object. If you have a look, you'll see the 3-argument version takes a name, a default value, and a RegistryValueOptions.

If Option Strict were on, it'd have helped you figure this out by giving you a compile error: Nothing isn't a valid value for the third parameter. Since Option Strict is off, the compiler is "helping" you by automatically converting it to 0. You think your code says, "Get the value of 'NoAutoRebootWithLoggedOnUser' from 'HKLM\SOFTWARE...', and return Nothing if the value cannot be retrieved." Instead, your code says, "Get the value of 'HKLM\SOFTWARE\...\AU' and return 'NoAutoRebootWithLoggedOnUser' if the valeu cannot be retrieved, do not use any optional behaviors." Obviously you can't retrieve the value of that key (it probably has no value), so you return the default.

Values are what live under keys. There's no overload of GetValue() that lets you specify a subkey path and a value name. But you can open subkeys and use the subkey's GetValue() method:

Using key As RegistryKey = My.Computer.Registry.LocalMachine.OpenSubKey("SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU")
    Dim value As Object = key.GetValue("NoAutoRebootWithLoggedOnUsers")
    Console.WriteLine(value)
    Console.ReadLine()
End Using

Alternatively, it looks like you're confused with My.Computer.Registry.GetValue(), which *does* have the 3-args version you tried to call:

Dim value As Object = My.Computer.Registry.GetValue("HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU", "NoAutoRebootWithLoggedOnUsers", Nothing)
Console.WriteLine(value)
Console.ReadLine()

This is why I never use the "My.Whatever" classes: they usually have a different API than the .NET classes that would normally do the job, and when they return the .NET API objects you can get quite confused as you have to remember which context you're in.

[chris1990]

thanks for your help.

@Sitten_Spynne: I am using your 2nd example, but still when i run the code it returns nothing 'no data', even though i know that the value is definitely 1. I've tried running the program with admin rights as well.

Dim Value As Object = My.Computer.Registry.GetValue("HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU", "NoAutoRebootWithLoggedOnUsers", "no data")
        MsgBox(Value)

[Sitten Spynne]

Works fine on my machine, and I copy/pasted your code. Double-check the registry key exists. Check your project settings. My projects are targeted for x86 but running on x64; maybe yours is different and that has an impact? I'm leaning towards "something's wrong with the key".

[chris1990]

I think its because the key's a dword, i've just tested a string and it works fine.

        Using key As RegistryKey = My.Computer.Registry.LocalMachine.OpenSubKey("SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU")
            Dim value As Object = key.GetValue("test")
            ''Dim value As Object = key.GetValue("NoAutoRebootWithLoggedOnUsers")
            MsgBox(value)
        End Using

[Sitten Spynne]

I think that's a red herring, because as I stated in #5 it works fine on my machine. Something else must be in play, or there's a difference between our environments that is causing the behavior.

[chris1990]

lol, I've just noticed my mistake after 2 days of trying to figure it out.

You was right, it was the wrong registry key 'NoAutoRebootWithLoggedOnUsers' it should of been 'NoAutoRebootWithLoggedOnUser'. Strange how the s has appeared, when i copied it from the code i used to write the key with.

i feel so stupid, thanks for your help.