Written by: Michael Washington
6/25/2011 9:28 AM 

This article describes how you can upload files using LightSwitch, and store them on the server hard drive. This is different from uploading files and storing them in the server database.

If you want to upload files and store them in the database, see How Do I: Import and Store a Data File by Matt Sampson.

The sample application contains an Upload File button.

This opens a file upload popup (this uses code from the Matt Sampson article).

After uploading the file, the file shows up in the File Records list.

Clicking on a file, then clicking the Download File button, will download the file.

Note: This example only works when the LightSwitch application is configured as a Web Application.

In the Visual Studio Solution Explorer, when we switch to File View…

We can see files were added to the ServerGenerated project, that provides the upload and download functionality.

If we unload the project…

…and edit the project file…

…we see the entries that were added to include the files in the project. Without doing this, the .ascx and .ashx files that were added would not be in the deployed project and the program would not work.

Note however, that any .cs code files are automatically compiled into assemblies and deployed. There is no need to reference them in the project file.

Don’t forget to reload the project!

When we publish the project…

The upload and download files are also deployed.

The Screen

To explore the code, let us first start with the Screen.

Displaying Files (WCF RIA Service)

To display the files that have been uploaded, we use a simple WCF RIA Service. See this article: Creating a Simple LightSwitch RIA Service (using POCO) for directions on creating a WCF RIA Service and consuming it in a LightSwitch application.

This code is used in the WCF RIA Service:

    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.ComponentModel.DataAnnotations;
    using System.Linq;
    using System.ServiceModel.DomainServices.Hosting;
    using System.ServiceModel.DomainServices.Server;
    using System.IO;
    using System.Web.Hosting;
    // TODO: Create methods containing your application logic.
    // TODO: add the EnableClientAccessAttribute to this class to expose this DomainService to clients.
    public class FileDomainService : DomainService
    {
        [Query(IsDefault = true)]
        public IQueryable<FileRecord> GetFileRecords()
        {
            return _LocalFiles.AsQueryable();
        }
        private readonly List<FileRecord> _LocalFiles;
        public FileDomainService()
        {
            _LocalFiles = new List<FileRecord>();
            string strFileDirectory= HostingEnvironment.MapPath(@"~\");
            // Find instance of "bin"
            int intPositionOfBin = strFileDirectory.ToLower().IndexOf("bin");
            if (intPositionOfBin > -1)
            {
                strFileDirectory = strFileDirectory.Substring(0, intPositionOfBin);
            }
            strFileDirectory = strFileDirectory + @"Files\";
            EnsureDirectory(new System.IO.DirectoryInfo(strFileDirectory));
            // Add all directories at this directory.
            DirectoryInfo objDirectoryInfo = new DirectoryInfo(strFileDirectory);
            string FolderName = objDirectoryInfo.Name;
           
            // Get the files in the directory
            foreach (var fi in objDirectoryInfo.EnumerateFiles().OrderBy(x => x.Name))
            {
                FileRecord objFileRecord = new FileRecord();
                objFileRecord.FileName = fi.Name;
                // Add file to the collection
                _LocalFiles.Add(objFileRecord);
            }
        }
        #region EnsureDirectory
        public static void EnsureDirectory(System.IO.DirectoryInfo oDirInfo)
        {
            if (oDirInfo.Parent != null)
                EnsureDirectory(oDirInfo.Parent);
            if (!oDirInfo.Exists)
            {
                oDirInfo.Create();
            }
        }
        #endregion
    }
    public class FileRecord
    {
        [Key]
        public string FileName { get; set; }
    }

Also, note the References that the project requires.

Uploading Files

We right-click on the Upload File button and select Edit Execute Code.

We use the .xaml popup, and code from the Matt Sampson article:

        /// from: http://blogs.msdn.com/b/rmattsampson/archive/2011/05/23/how-to-import-and-store-a-data-file.aspx
        partial void ImportAFile_Execute()
        {
            // To invoke our own dialog, we have to do this inside of the "Main" Dispatcher
            // And, since this is a web application, we can't directly invoke the Silverlight OpenFileDialog
            // class, we have to first invoke our own Silverlight custom control (i.e. SelectFileWindow)
            // and that control will be able to invoke the OpenFileDialog class (via the Browse button)
            Dispatchers.Main.BeginInvoke(() =>
            {
                SelectFileWindow selectFileWindow = new SelectFileWindow();
                selectFileWindow.Closed += new EventHandler(selectFileWindow_Closed);
                selectFileWindow.Show();
            });
        }

The following method is called when the window is closed:

        void selectFileWindow_Closed(object sender, EventArgs e)
        {
            SelectFileWindow selectFileWindow = (SelectFileWindow)sender;
            // Continue if they hit the OK button AND they selected a file
            if (selectFileWindow.DialogResult == true && (selectFileWindow.FileInfoFile != null))
            {
                Dispatchers.Main.BeginInvoke(() =>
                {
                    UploadFile(selectFileWindow.FileInfoFile);
                });
            }
        }

This code determines where the .ashx upload file handler is and starts the upload:

        #region UploadFile
        private void UploadFile(FileInfo SelectedFile)
        {
            // If there is a file upload it
            if (SelectedFile != null)
            {
                // Get the upload URL
                string strURLWithSelectedFolder = string.Format("{0}{1}", GetBaseAddress(), "FileUpload.ashx");
                Uri uri = new Uri(strURLWithSelectedFolder, UriKind.Absolute);
                UploadUrl = uri;
                // Create an FileUpload object
                SimpleMVVMFileUpload.FileUpload upload = 
                    new SimpleMVVMFileUpload.FileUpload(this.DataWorkspace.Details.Dispatcher, UploadUrl, SelectedFile);
                upload.ChunkSize = 4194304;
                // Wire up handles for status changed and upload percentage
                // These will be updating the properties that the ViewModel exposes
                upload.StatusChanged += new EventHandler(upload_StatusChanged);
                upload.UploadProgressChanged += 
                    new SimpleMVVMFileUpload.ProgressChangedEvent(upload_UploadProgressChanged);
                // Start the Upload
                upload.Upload();
            }
        }
        #endregion

(note: for a full explanation of the file upload code, see this article: Silverlight View Model Style File Manager Drag and Drop Upload)

When the file has completed uploading, the file list is refreshed:

        #region upload_StatusChanged
        void upload_StatusChanged(object sender, EventArgs e)
        {
            SimpleMVVMFileUpload.FileUpload fu = sender as SimpleMVVMFileUpload.FileUpload;
            // Is upload complete?
            if (fu.Status == SimpleMVVMFileUpload.FileUploadStatus.Complete)
            {
                this.FileRecords.Refresh();
            }
        }
        #endregion

Downloading Files

For downloading files, we first look at the CanExecute code that disables the button if no file is selected:

        #region DownloadFile_CanExecute
        partial void DownloadFile_CanExecute(ref bool result)
        {
            // Do not allow download if no file selected
            result = (this.FileRecords.SelectedItem != null);
        }
        #endregion

Next, we look at the Execute code simply calls Download.aspx file, passing the name of the file to download:

        #region DownloadFile_Execute
        partial void DownloadFile_Execute()
        {
            Dispatchers.Main.Invoke(() =>
            {
                HtmlPage.Window.Navigate(new Uri(string.Format("{0}",
                    String.Format(@"DownloadFile.aspx?FileName={0}",
                    this.FileRecords.SelectedItem.FileName)), UriKind.Relative), "_new");
            });
        } 
        #endregion

The following is the code for DownloadFile.aspx:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
namespace LightSwitchApplication.FileManager
{
    public partial class DownloadFile : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            // Get parameters
            string FileName = Request.QueryString["FileName"];
            // All parameters must have a value or return nothing
            if (
                FileName != ""
                )
            {
                try
                {
                    string path = MapPath(@"~\");               
                    // Find instance of "bin"
                    int intPositionOfBin = path.ToLower().IndexOf("bin");
                    if (intPositionOfBin > -1)
                    {
                        path = path.Substring(0, intPositionOfBin);
                    }
                    path = path + @"Files\";
                    // Remove any .. to prevent backing up directories
                    FileName = FileName.Replace("..", ""); 
                    string strPath = Path.Combine(path, FileName);
                    // Return the file
                    Response.ClearHeaders();
                    Response.AddHeader("content-disposition", string.Format("attachment; filename={0}", FileName));
                    Response.ClearContent();
                    Response.ContentEncoding = System.Text.Encoding.UTF8;
                    Response.ContentType = GetContentType(strPath);
                    FileStream sourceFile = new FileStream(strPath, FileMode.Open);
                    long FileSize;
                    FileSize = sourceFile.Length;
                    byte[] getContent = new byte[(int)FileSize];
                    sourceFile.Read(getContent, 0, (int)sourceFile.Length);
                    sourceFile.Close();
                    Response.BinaryWrite(getContent);
                    Response.Flush();
                    Response.Close();
                }
                catch (Exception ex)
                {
                    lblDisplayFilesError.Text = ex.Message;
                }
            }
        }
        #region GetContentType
        public string GetContentType(string strextension)
        {
            string contentType;
            switch (strextension.ToLower())
            {
                case ".gif":
                    contentType = "image/gif";
                    break;
                case ".jpg":
                case ".jpeg":
                    contentType = "image/jpeg";
                    break;
                case ".png":
                    contentType = "image/png";
                    break;
                case ".doc":
                    contentType = "application/ms-word";
                    break;
                case ".docx":
                    contentType = "application/vnd.ms-word.document.12";
                    break;
                case ".pdf":
                    contentType = "application/pdf";
                    break;
                case ".xls":
                    contentType = "application/vnd.ms-excel";
                    break;
                case ".ppt":
                    contentType = "application/vnd.ms-powerpoint";
                    break;
                case ".zip":
                    contentType = "application/zip";
                    break;
                case ".txt":
                    contentType = "text/plain";
                    break;
                default:
                    contentType = "application/octet-stream";
                    break;
            }
            return contentType;
        }
        #endregion
    }
}

Download Code

The LightSwitch project is available at http://lightswitchhelpwebsite.com/Downloads.aspx

(note: When you deploy the application, you must give permission to the web server process to access the files on the file system)

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Tags: Applications , WCF RIA Service

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