This example demonstrates how to implement a custom file system provider that bounds ASPxFileManager to a LINQ to SQL data source. The provider retrieves data from data context ( a DbFileSystemDataContext object) connected to a database that contains file/folder structure and contents.
To decrease the number of recursive LINQ to SQL queries, a folder list is cached in memory (see the FolderCache property and the RefreshFolderCache method).
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WebSite/App_Code/LinqFileSystemProvider.cs(vb)
C#using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using DevExpress.Web;
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, dbItem.Id.ToString());
}
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, dbItem.Id.ToString());
}
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
}));
}
public override void CopyFile(FileManagerFile file, FileManagerFolder newParentFolder) {
var dbFileItem = FindDbFileItem(file);
CopyCore(dbFileItem, newParentFolder.RelativeName, false);
}
public override void CopyFolder(FileManagerFolder folder, FileManagerFolder newParentFolder) {
List<FileManagerFolder> folders = new List<FileManagerFolder>();
FillSubFoldersList(folder, folders);
int folderNameOffset = !string.IsNullOrEmpty(folder.Parent.RelativeName) ? folder.Parent.RelativeName.Length + 1 : 0;
foreach (FileManagerFolder copyingFolder in folders) {
DbFileSystemItem dbFolderItem = FindDbFolderItem(copyingFolder);
string folderPath = newParentFolder.RelativeName;
if (copyingFolder != folder)
folderPath = Path.Combine(folderPath, copyingFolder.Parent.RelativeName.Substring(folderNameOffset));
CopyCore(dbFolderItem, folderPath, true);
foreach (FileManagerFile currentFile in copyingFolder.GetFiles()) {
DbFileSystemItem dbFileItem = FindDbFileItem(currentFile);
CopyCore(dbFileItem, Path.Combine(folderPath, copyingFolder.Name), false);
}
}
}
void FillSubFoldersList(FileManagerFolder folder, List<FileManagerFolder> list) {
list.Add(folder);
foreach (FileManagerFolder subFolder in folder.GetFolders())
FillSubFoldersList(subFolder, list);
}
void CopyCore(DbFileSystemItem item, string path, bool isFolder) {
FileManagerFolder newParentFolder = new FileManagerFolder(this, path);
UpdateAndSubmitChanges(newParentFolder,
dbItem => DataContext.DbFileSystemItems.InsertOnSubmit(new DbFileSystemItem() {
Name = item.Name,
Data = item.Data,
ParentId = dbItem.Id,
LastWriteTime = DateTime.Now,
IsFolder = isFolder
}));
}
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();
}
}
// Get file size (length).
public override long GetLength(FileManagerFile file) {
return FindDbFileItem(file).Data.Length;
}
}
WebSite/Default.aspx
ASPx<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<%@ Register Assembly="DevExpress.Web.v15.1, Version=15.1.15.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" Namespace="DevExpress.Web" TagPrefix="dx" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<dx:ASPxFileManager ID="ASPxFileManager1" runat="server" SettingsUpload-AdvancedModeSettings-EnableMultiSelect="true"
OnFileUploading="ASPxFileManager1_FileUploading"
OnFolderCreating="ASPxFileManager1_FolderCreating"
OnItemDeleting="ASPxFileManager1_ItemDeleting"
OnItemMoving="ASPxFileManager1_ItemMoving"
OnItemRenaming="ASPxFileManager1_ItemRenaming"
OnItemCopying="ASPxFileManager1_ItemCopying"
CustomFileSystemProviderTypeName="LinqFileSystemProvider">
<Settings RootFolder="a1" ThumbnailFolder="~\Thumb\" />
<SettingsDataSource />
<SettingsEditing AllowCreate="True" AllowDelete="True" AllowMove="True" AllowRename="True" AllowCopy="true" />
<SettingsFileList View="Thumbnails"></SettingsFileList>
</dx:ASPxFileManager>
</form>
</body>
</html>