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Isolated Storage in .Net



Namespace: System.IO.IsolatedStorage


IsolatedStoreage is a storage place provided to applications with full access writes where they can store data about themselves. It also prevents from the attacks intended by spywares, malwares, and viruses. And application will run without caring about the environment whether it is limited, partially, or fully trusted environment.

How to create a store:
An isolated storage can be created by just calling the respective scope level Get[Machine|User]StoreFor[Application|Assembly|Domain]();

IsolatedStorageFileStream class:
This class inherits from FileStream class, so its use is identical to FileStream class.

Reading and writing data to Isolated Storage:

IsolatedStorageFile userStore = IsolatedStoreageFile.GetUserStoreForAssembly();
IsolatedStorageFileStream vUserFileStream = new IsolatedStorageFileStream(“UserSettings.set”,
                                                                                                                                FileMode.Create, userStore);

StreamWriter sw = new StreamWriter(vUserFileStream);
Sw.WriteLine(“testing testing ….”);

Sw.Close();

There is no way to check existence of a file like Exists method. One will have to query the files in the store and then check whether the respective file exists in list or not.
String[] files = userStore.GetFileNames(“UserSettings.set”); //only  * and ? are supported wildcards
If(files.length > 0)
{
                //File exists
}

Creating Directories in Isolated Storage:

UserStore.CreateDirectory(“UI”);
IsolatedStorageFileStream newUISetting = new IsolatedStorageFileStream(
@“UI\UserSetting.set”,
FileMode.Create,
userStore);

In the same way one can check for the existence of a directory:

String[] dirs = userStore.GetDirectoriesNames(“UI”);
If(dirs.length > 0)
{
                //Directory exists
}

IsolatedStorageFilePermission class:

IsolatedStorageFilePermission class encapsulates checks to enable Code Access permission. One can configure the level of store and size quota that an assembly, application or domain can consume.

[IsolatedStorageFilePermission(SecurityAction.Demand)]
Class program
{
}

OR

[IsolatedStorageFilePermission(SecurityAction.Demand, UserQuota = 1024, UsageAllowed= IsolatedStorageContainment.AssemblyIsolationByUser)]
Class program
{
}


IsolatedStorageFile class:

Static Methods:
GetEnumerator
Gets the enumerator for the IsolatedStorageFile stores within an isolated storage scope.
GetMachineStoreForApplication
Obtains machine-scoped isolated storage corresponding to the calling code's application identity.
GetMachineStoreForAssembly
Obtains machine-scoped isolated storage corresponding to the calling code's assembly identity.
GetMachineStoreForDomain
Obtains machine-scoped isolated storage corresponding to the application domain identity and the assembly identity.
GetStore
Overloaded. Obtains isolated storage corresponding to the given application domain and assembly evidence objects and isolated storage scope.
GetUserStoreForApplication
Obtains user-scoped isolated storage corresponding to the calling code's application identity.
GetUserStoreForAssembly
Obtains user-scoped isolated storage corresponding to the calling code's assembly identity.
GetUserStoreForDomain
Obtains user-scoped isolated storage corresponding to the application domain identity and assembly identity.

IsolatedStorageFile Properties:
ApplicationIdentity
Gets an application identity that scopes isolated storage.
AssemblyIdentity
Gets an assembly identity used to scope isolated storage.
CurrentSize
Gets the current size of the isolated storage. (Overrides .CurrentSize.)
DomainIdentity
Gets a domain identity that scopes isolated storage.
MaximumSize
Gets a value representing the maximum amount of space available for isolated storage within the limits established by the quota. (Overrides .MaximumSize.)
Scope
Gets an IsolatedStorageScope enumeration value specifying the scope used to isolate the store.

IsolatedStorageFile Methods:
Close
Closes a store previously opened with GetStore, GetUserStoreForAssembly(), or GetUserStoreForDomain().
CreateDirectory
Creates a directory in the isolated storage scope.
DeleteDirectory
Deletes a directory in the isolated storage scope.
DeleteFile
Deletes a file in the isolated storage scope.
Dispose
Releases all resources used by the IsolatedStorageFile.
GetDirectoryNames
Enumerates directories in an isolated storage scope that match a given pattern.
GetFileNames
Enumerates files in isolated storage scope that match a given pattern.
Remove
Overloaded. Removes the isolated storage scope and all its contents.



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