CODEWITHSUNDEEP
c#registryiteration
Simon Lausten
Simon Lausten

Reputation: 37

Iterating Registry, looking for Values

Scenario : We do not care about Performance. We have an Array of Values that we need to check for in the registry. //The Values can have anything infront of them. We need to change this.

Right now, I don't feel like it itterates all the Values, it's like it skips a few and in the end becomes null and crashes.

This is a console Program, Main looks like this :

static void Main(string[] args)
    {

        string[] FASKeyWords = new string[] { "DummyValue1", "DummyValue2" };
        RegistryKey BaseKey = Registry.LocalMachine;
        foreach (string FASKeyWord in FASKeyWords)
        {
            Console.WriteLine("Looking in " + BaseKey.Name);
            Console.WriteLine("Looking for : " + FASKeyWord);
            GetSubKeys(BaseKey, FASKeyWord);
        }
    }

Now, Main calls this Void

private static void GetSubKeys(RegistryKey SubKey,string KeyWord)
        {
            foreach (string valueName in SubKey.GetValueNames())
            {
                string Value = SubKey.GetValue(valueName).ToString();
//Check for any values at all.
                MessageBox.Show(valueName + " with data : " + Value);

                if (Value.Contains(KeyWord))
                    MessageBox.Show("Found '" + KeyWord + "' At " + SubKey.Name);
            }

            foreach (string Key in SubKey.GetSubKeyNames())
            {
                MessageBox.Show(SubKey.Name);
                GetSubKeys(SubKey.OpenSubKey(Key), KeyWord);
            }
        }

I'm far from the best working with the Registry class, but to my knowledge this should be okay right? , I've been starring blindly at it for far too long now, I figured it would be good with another pair of eyes :)

The Crash happens at : string Value = SubKey.GetValue(valueName).ToString(); with a NullReferenceException In Addition it does not Show a messageBox with all the Values inside a Key, It's like it just picks em out randomly.

A visual on the problem. http://peecee.dk/uploads/122012/Untitled2.png

Upvotes: 2

Views: 156

Answers (1)

Adriano Repetti
Adriano Repetti

Reputation: 67090

From MSDN:

GetValue does not support reading values of type REG_NONE or REG_LINK. In both cases, the default value (null) is returned instead of the actual value.

You better to handle that situation (at least with a simple if):

object RawValue = SubKey.GetValue(valueName);
string Value = RawValue != null ? RawValue.ToString() : "";

Upvotes: 2

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