ReadLine ; txtData. WriteLine line ; wi. AvailableFree shows the total free space available. When we call IsolatedStorageFile IncreaseQuotaTo method then a dialog box is displayed which gives user the option to allow or deny the IsolatedStorage size increase.
Serializing objects with Xml Serializer XmlSeriallizer is another option to serialize and deserialize objects rather than individual pieces of data using the StreamReader and StreamWriter. XmlSerializer can serialize objects into bytes and deserialize bytes back to the object.
To use XmlSerializer we need to assure two things for a class:. View All. Isolated Storage in Silverlight. Ashish Shukla Updated date Jul 19, To use XmlSerializer we need to assure two things for a class: The class must have public no argument or default constructor.
End Using. End Sub. If you are interested in knowing the location of the Isolated Storage space, then on my Vista box, the file gets created in:. On a XP box, the location would be:.
Read from a file kept in the Isolated Storage. Open, store. ReadLine ;. How to increase the Isolated Storage space? If you want to request the user to increase the storage space, you can use the following code to request an increase by 3 MB.
GetUserStoreForApplication ;. IncreaseQuotaTo incSpace ;. Perform your actions. You have only 1MB of space. Dispose ;. IncreaseQuotaTo incSpace. If b Then. End If. Catch ise As IsolatedStorageException. End Try. When the code is run, the site will prompt the user for approval to utilize more space on their machines.
The prompt displays the current storage space being used and the space, the application is requesting to be increased. How to reduce the Isolated Storage space? You cannot do that in Beta 2. At least I could not find a way of reduce the space.
Applications may ask for more space if the initial amount is insufficient for some reason. There is no guarantee that the request will succeed. Silverlight will ask the user if they are happy to grant the application more space. By the way, you are only allowed to ask for more storage in response to user input, such as a click. If you try to ask it some other time, such as when the plug-in loads, or in a timer handler, Silverlight will automatically fail the request without even prompting the user.
Extra quota is only available to the applications with which the user is interacting. Note that even an empty subdirectory consumes some of your quota because the operating system needs to allocate space on disk to represent the directory. So, the available space may be less than the total quota, minus the sum size of all your files.
If you do not have sufficient space to proceed, you ask for more by calling the IncreaseQuotaTo method. Here we are using the third property, Quota , to discover the current quota size, and then we are adding the amount extra we require to get our new requested quota.
The method returns either True or False to indicate whether we are allocated what we asked for. This includes the data stored in isolated storage as well as some additional overhead for each directory and new file created 1KB each.
Unlike the. NET Framework, Silverlight uses a concept called quota groups for managing quotas in isolated storage. A quota group is a group of isolated stores that share the same quota. In Silverlight, stores are grouped by site, so all applications that have the same site identity share the same isolated storage quota.
For example, all applications hosted on microsoft. Isolated storage can have zero or more quota groups. Figure 3 shows two hypothetical quota groups: one for microsoft. Each quota group has at most one shared site store and zero or more application stores. By default, each quota group is assigned a default quota of 1MB. This should be enough space for applications to store simple settings and text files in isolated storage.
However, since the quota is shared across all applications from the same site, the quota can easily be reached if just one of the applications uses a lot of space. If a site hosts several Silverlight applications and each application stores data in isolated storage, the amount of free space can diminish quickly. In addition, if an application needs to save a lot of data on the client, 1MB of free space won't always be enough.
To address this, if an application needs more space in isolated storage, it can request a larger quota. When an application requests a larger quota, Silverlight prompts the end user to allow or deny the request. The following code shows how to request a larger quota:.
In this code, the AvailableFreeSpace property is used to determine how much free space is available in isolated storage. The code knows it needs 5MB of free space. And if 5MB is not available, it requests a larger quota by calling IncreaseQuotaTo passing it the requested quota size in bytes in this case the current quota plus the additional space that's needed.
The call to IncreaseQuota must be made from a user-initiated event, such as within a handler for a button-click event. If it is not called from a user-initiated event, Silverlight will not prompt the user and the request will be denied the method will return false. If called from a user-initiated event and the end user allows the request, IncreaseQuotaTo returns true and the quota for the group is increased to the requested size.
Because quotas are per site in Silverlight, you may want to host your Silverlight application differently depending upon the needs of your site and application. For example, imagine you're creating a Silverlight video player that saves the user's top 10 favorite videos in isolated storage. Each video can be up to 10MB, which means the application will need to increase the quota to something more than MB. You could host the application on your main site for example, contoso.
But if there are many other Silverlight applications on contoso. To solve this, you may want to consider hosting the video player application on its own sub domain such as player. Similarly, if you plan to create a suite of Silverlight applications that need to share data, you'll want to host all of them on the same site and make sure they work well together.
Silverlight uses quota groups to make it easier for end users to manage the use of isolated storage on their computers. Instead of being presented with a laundry list of URLs to different Silverlight XAP files, end users are presented with a list of Web sites that are using isolated storage. This way, end users can quickly decide which Web sites they trust and which Web sites they do not trust to store data on their machines. To end users, isolated storage is known as Application Storage.
An end user can manage isolated storage using the Silverlight Configuration dialog. To open the dialog, right-click on any Silverlight application that's running in a Web browser and click Silverlight Configuration in the menu that pops up.
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