Using isolated storage for application-specific data in C# .NET Part 4: various

In the previous post we looked at how to find the location of a file when stored in isolated storage. We saw that isolated storage files have also a “normal” file path that you can navigate to in file explorer. The file paths are difficult to guess as they have complicated names but they are not secured in any way.

In this post we’ll briefly look at some various other things about isolated storage mainly related to size and quota.

Every application that uses isolated storage has a defined quota in bytes that it can use. Normally the default quota for partially trusted applications, e.g. those that you download from the internet, is 1MB. The IsolatedStorageFile object exposes a couple of properties that describe the quota, the available space and the size used:

IsolatedStorageFile applicationStorageFileForUser = IsolatedStorageFile.GetUserStoreForAssembly();
			
Debug.WriteLine(applicationStorageFileForUser.AvailableFreeSpace);
Debug.WriteLine(applicationStorageFileForUser.Quota);
Debug.WriteLine(applicationStorageFileForUser.UsedSize);

If the quota is not enough you can request a new upper limit using the IncreaseQuotaTo method of the IsolatedStorageFile class:

bool quotaIncreaseSuccess = applicationStorageFileForUser.IncreaseQuotaTo(some number);

The method will throw an exception if you’re trying to reduce the quota, i.e. set a lower number than the current quota.

Read all posts dedicated to file I/O here.