FileSystemProviderBase Class
Serves as the base class for providers that perform operations with the file system.
Namespace: DevExpress.Web
Assembly: DevExpress.Web.v24.2.dll
Declaration
Related API Members
The following members return FileSystemProviderBase objects:
| Library | Related API Members |
|---|---|
| ASP.NET Web Forms Controls | ASPxFileManager.CustomFileSystemProvider |
| HtmlEditorFileManagerSettingsBase.CustomFileSystemProvider | |
| ASP.NET MVC Extensions | FileManagerSettings.CustomFileSystemProvider |
Remarks
The FileSystemProviderBase class is the base class that implements the common file system provider functionality.
This class can be used as an ancestor of your custom file system provider. In this case, you should provide the implementation of the class’s methods. To learn more, see the Custom File System Provider topic.
Example
using DevExpress.Web.ASPxFileManager;
using System.IO;
public class LinqFileSystemProvider : FileSystemProviderBase {
const int DbRootItemId = 1;
DbFileSystemDataContext dataContext;
Dictionary<int, DbFileSystemItem> folderCache;
string rootFolderDisplayName;
public LinqFileSystemProvider(string rootFolder)
: base(rootFolder) {
this.dataContext = new DbFileSystemDataContext();
RefreshFolderCache();
}
public DbFileSystemDataContext DataContext { get { return dataContext; } }
// Used to decrease the number of recursive LINQ to SQL queries made to a database
public Dictionary<int, DbFileSystemItem> FolderCache { get { return folderCache; } }
public override string RootFolderDisplayName { get { return rootFolderDisplayName; } }
public override IEnumerable<FileManagerFile> GetFiles(FileManagerFolder folder) {
DbFileSystemItem dbFolderItem = FindDbFolderItem(folder);
return
from dbItem in DataContext.DbFileSystemItems
where !dbItem.IsFolder && dbItem.ParentId == dbFolderItem.Id
select new FileManagerFile(this, folder, dbItem.Name);
}
public override IEnumerable<FileManagerFolder> GetFolders(FileManagerFolder parentFolder) {
DbFileSystemItem dbFolderItem = FindDbFolderItem(parentFolder);
return
from dbItem in FolderCache.Values
where dbItem.IsFolder && dbItem.ParentId == dbFolderItem.Id
select new FileManagerFolder(this, parentFolder, dbItem.Name);
}
public override bool Exists(FileManagerFile file) {
return FindDbFileItem(file) != null;
}
public override bool Exists(FileManagerFolder folder) {
return FindDbFolderItem(folder) != null;
}
public override System.IO.Stream ReadFile(FileManagerFile file) {
return new MemoryStream(FindDbFileItem(file).Data.ToArray());
}
public override DateTime GetLastWriteTime(FileManagerFile file) {
var dbFileItem = FindDbFileItem(file);
return dbFileItem.LastWriteTime.GetValueOrDefault(DateTime.Now);
}
// File/folder management operations
public override void CreateFolder(FileManagerFolder parent, string name) {
UpdateAndSubmitChanges(parent,
dbItem => DataContext.DbFileSystemItems.InsertOnSubmit(new DbFileSystemItem() {
IsFolder = true,
LastWriteTime = DateTime.Now,
Name = name,
ParentId = dbItem.Id
}));
}
public override void DeleteFile(FileManagerFile file) {
UpdateAndSubmitChanges(file, dbItem =>
DataContext.DbFileSystemItems.DeleteOnSubmit(dbItem));
}
public override void DeleteFolder(FileManagerFolder folder) {
UpdateAndSubmitChanges(folder, dbItem =>
DataContext.DbFileSystemItems.DeleteOnSubmit(dbItem));
}
public override void MoveFile(FileManagerFile file, FileManagerFolder newParentFolder) {
UpdateAndSubmitChanges(file, dbItem => dbItem.ParentId =
FindDbFolderItem(newParentFolder).Id);
}
public override void MoveFolder(FileManagerFolder folder, FileManagerFolder newParentFolder)
{
UpdateAndSubmitChanges(folder, dbItem => dbItem.ParentId =
FindDbFolderItem(newParentFolder).Id);
}
public override void RenameFile(FileManagerFile file, string name) {
UpdateAndSubmitChanges(file, dbItem => dbItem.Name = name);
}
public override void RenameFolder(FileManagerFolder folder, string name) {
UpdateAndSubmitChanges(folder, dbItem => dbItem.Name = name);
}
public override void UploadFile(FileManagerFolder folder, string fileName, Stream content) {
UpdateAndSubmitChanges(folder,
dbItem => DataContext.DbFileSystemItems.InsertOnSubmit(new DbFileSystemItem() {
Name = fileName,
Data = ReadAllBytes(content),
ParentId = dbItem.Id,
LastWriteTime = DateTime.Now,
IsFolder = false
}));
}
protected void UpdateAndSubmitChanges(FileManagerFile file, Action<DbFileSystemItem> update)
{
UpdateAndSubmitChangesCore(FindDbFileItem(file), update);
}
protected void UpdateAndSubmitChanges(FileManagerFolder folder, Action<DbFileSystemItem>
update) {
UpdateAndSubmitChangesCore(FindDbFolderItem(folder), update);
}
protected void UpdateAndSubmitChangesCore(DbFileSystemItem dbitem, Action<DbFileSystemItem>
update) {
update(dbitem);
DataContext.SubmitChanges();
RefreshFolderCache();
}
protected DbFileSystemItem FindDbFileItem(FileManagerFile file) {
DbFileSystemItem dbFolderItem = FindDbFolderItem(file.Folder);
if(dbFolderItem == null)
return null;
return
(from dbItem in DataContext.DbFileSystemItems
where dbItem.ParentId == dbFolderItem.Id && !dbItem.IsFolder && dbItem.Name ==
file.Name
select dbItem).FirstOrDefault();
}
protected DbFileSystemItem FindDbFolderItem(FileManagerFolder folder) {
return
(from dbItem in FolderCache.Values
where dbItem.IsFolder && GetRelativeName(dbItem) == folder.RelativeName
select dbItem).FirstOrDefault();
}
// Returns the path to a specified folder relative to a root folder
protected string GetRelativeName(DbFileSystemItem dbFolder) {
if(dbFolder.Id == DbRootItemId) return string.Empty;
if(dbFolder.ParentId == DbRootItemId) return dbFolder.Name;
if(!FolderCache.ContainsKey(dbFolder.ParentId)) return null;
string name = GetRelativeName(FolderCache[dbFolder.ParentId]);
return name == null ? null : Path.Combine(name, dbFolder.Name);
}
// Caches folder names in memory and obtains a root folder's name
protected void RefreshFolderCache() {
this.folderCache = (
from dbItem in DataContext.DbFileSystemItems
where dbItem.IsFolder
select dbItem
).ToDictionary(i => i.Id);
this.rootFolderDisplayName = (
from dbItem in FolderCache.Values
where dbItem.Id == DbRootItemId
select dbItem.Name).First();
}
protected static byte[] ReadAllBytes(Stream stream) {
byte[] buffer = new byte[16 * 1024];
int readCount;
using(MemoryStream ms = new MemoryStream()) {
while((readCount = stream.Read(buffer, 0, buffer.Length)) > 0) {
ms.Write(buffer, 0, readCount);
}
return ms.ToArray();
}
}
}
Inheritance
Show 16 items
Object
FileSystemProviderBase
See Also