All about WP7 Isolated Storage - Files and Folders

by WindowsPhoneGeek

This is the second article from the "All about WP7 Isolated Storage " series of short articles focused on real practical examples with source code rather than a plain theory. I am going to talk about creating folders and files in the Windows Phone 7 Isolated Storage.

• All about WP7 Isolated Storage - intro to Isolated Storage
• All about WP7 Isolated Storage - Folders and Files
• All about WP7 Isolated Storage - Store data in IsolatedStorageSettings
• All about WP7 Isolated Storage - Read and Save Text files
• All about WP7 Isolated Storage - Read and Save XML files using XmlSerializer
• All about WP7 Isolated Storage - Read and Save XML files using XmlWriter
• All about WP7 Isolated Storage - Read and Save Images
• All about WP7 Isolated Storage - Read and Save Captured Image
• All about WP7 Isolated Storage - Read and Save Binary files
• All about WP7 Isolated Storage - File manipulations
• All about WP7 Isolated Storage - Recommendations and Best Practices
• All about WP7 Isolated Storage - open source Databases and Helper libraries

To begin with lets first create a sample Windows Phone 7 application project. Next include the following namespaces in MainPage.xaml.cs (alternatively you can use the code in another page):

using System.IO;
using System.IO.IsolatedStorage;

Folders in the WP7 Isolated Storage

• Create Folder

In order t create a folder called "New Folder", we can just invoke the method CreateDirectory of the instance of the class IsolatedStorageFile:

IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication(); 
myIsolatedStorage.CreateDirectory("NewFolder");

NOTE: Instead of "NewFolder" you can specify another more composite path like for example"Folder1/Folder2/Folder3/NewFolder".

myIsolatedStorage.CreateDirectory("Folder1/Folder2/Folder3/NewFolder");

• Delete Folder

To delete a folder just invoke the DeleteDirectory of the instance of the class IsolatedStorageFile:

myIsolatedStorage.DeleteDirectory("NewFolder");

• Best Practices

- Always check if the Directory exists

myIsolatedStorage.DirectoryExists(directoryName)

- Always use  try{}catch{} when working with the Isolated Storage to prevent any unexpected exception to be seen by the user. Here is an example of a method that create Directory  with a given name:

public void CreateDirectory(string directoryName)
 {
    try
    {
        IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication();
        if(!string.IsNullOrEmpty(directoryName) && !myIsolatedStorage.DirectoryExists(directoryName))
        {
          myIsolatedStorage.CreateDirectory(directoryName);
        }
    }
    catch (Exception ex)
    {
        // handle the exception
    }
}

 To create a directory just call the method and add as a parameter the desired name:

this.CreateDirectory("NewFolder");

-Alternatively use the same checks when deleting folders:

NOTE: A directory must be empty before it is deleted. The deleted directory cannot be recovered once deleted.

public void DeleteDirectory(string directoryName)
{
    try
    {
        IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication();
        if (!string.IsNullOrEmpty(directoryName) && myIsolatedStorage.DirectoryExists(directoryName))
        {
            myIsolatedStorage.DeleteDirectory(directoryName);
        }
    }
    catch (Exception ex)
    {
        // handle the exception
    }
}

To delete a folder just call the method:

this.DeleteDirectory("NewFolder");

NOTE: Currently it is not possible to Rename a Directory in the Isolated Storage.

Files in the WP7 Isolated Storage

• Create File

To create a new file named "SomeFile.txt" just use the StreamWriter :

IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication();
StreamWriter writeFile = new StreamWriter(new IsolatedStorageFileStream("NewFolder\\SomeFile.txt", FileMode.CreateNew, myIsolatedStorage));

NOTE: If you do not specify any folder then the file will be created in the root folder. You can also create files using IsolatedStorageFileStream:

IsolatedStorageFileStream stream1 = new IsolatedStorageFileStream("SomeTextFile.txt", FileMode.Create, myIsolatedStorage);

• Delete File

To delete a file from Isolated Storage just invoke the DeleteFile of the instance of the class IsolatedStorageFile:

myIsolatedStorage.DeleteFile("NewFolder/SomeFile.txt");

• Best Practices

- Always check if the Directory in which you want to create/delete a File exists

myIsolatedStorage.DirectoryExists(directoryName)

- Always check if the file already exists myIsolatedStorage.FileExists(filePath). If so you will have to delete the old file before creating a new one.

- Always use  try{}catch{} when working with the Isolated Storage to prevent any unexpected exception to be seen by the user. Here is an example of a method that create Directory  with a given name:

try
{
    IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication();
    StreamWriter writeFile;
    if (!myIsolatedStorage.DirectoryExists("NewFolder"))
    {
        myIsolatedStorage.CreateDirectory("NewFolder");
        writeFile = new StreamWriter(new IsolatedStorageFileStream("NewFolder\\SomeFile.txt", FileMode.CreateNew, myIsolatedStorage));
    }
    else
    {
        writeFile = new StreamWriter(new IsolatedStorageFileStream("NewFolder\\SomeFile.txt", FileMode.CreateNew, myIsolatedStorage));
    }
    
}
catch (Exception ex)
{
    // do something with exception
}

NOTE: To completely  remove all stores in the IsolatedStorage just call for store.Remove() where "store" is an instance of the IsolatedStorageFile.

In this article I talked about creating Folders and Files in the WP7 Isolated Storage. Stay tuned with the rest of the posts.

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Comments

        catch
        {
            this.CreateDirectory("userData");
            infoStatus.Visibility = System.Windows.Visibility.Collapsed;

        }
    }

        //Delete User Directory            
        IsolatedStorageFile myStore = IsolatedStorageFile.GetUserStoreForApplication();
        myStore.DeleteDirectory("userData");
        //Navigate back to HomePage
        NavigationService.Navigate(new Uri("/MainPage.xaml", UriKind.Relative));
    }