从.net应用程序访问注册表

Question

I have a class in which in the constructor i am trying to read a value from registry for a key. The value is returned back as null and throws the following exception when I try to set the event log name to the value returned from registry (which is turning out to be null in this case):

System.ArgumentNullException: Value cannot be null.
Parameter name: value
at System.Diagnostics.EventLog.SetLogName(String currentMachineName, String value)
at System.Diagnostics.EventLog.set_Log(String value)
at Net.GVN.EventLogging.EventLogger.set_Log(String value)
at Net.BusinessEntities.Sel.get_SelEntityEventLogger()
at Net.BusinessEntities.Sel..ctor() 

Please find below the code which is written for registry access.

---

object keyVal =
            Registry.GetValue(SEL_ENTITY_REGISTRY_KEY,
            "EventLogName", string.Empty);

        this._logName = (keyVal == null) ? null : keyVal.ToString();

---

But when I write another .net application in which I just read the same registry value, this application returns back the registry values. The new application also has the same code as mentioned above.

So does not look like permission issue. Can someone help me regarding what the issue might be please. Thanks for your help in advance.

Thanks & Regards...

Answer 1

Before you get a value you must specify where you are getting it from.

GetValue's parameters are a key name, the name of the value, and the default value.

No where in your code(That I can see.) are you actually opening a registry path.

Instead to get the specified value that you want:

//make a reference to what part of the registry you want. In this case I chose Current User
RegistryKey myRootKey = Registry.CurrentUser;

//Open the specified subkey below the root key
RegistryKey selectedSubKey = myRootKey.OpenSubKey("FirstSubKey\\Child1\\Child2");

//Now you can use selectedSubKey to have access to all values WITHIN Child2
object keyval = selectedSubKey.GetValue("myValueName");