File Upload ASP.NET MVC 3.0

Question

(Preface: this question is about ASP.NET MVC 3.0 which was released in 2011, it is not about ASP.NET Core 3.0 which was released in 2019)

I want to upload file in asp.net mvc. How can I upload the file using html input file control?

Answer 1

to transfer to byte[] (e.g. for saving to DB):

using (MemoryStream ms = new MemoryStream()) {     file.InputStream.CopyTo(ms);     byte[] array = ms.GetBuffer(); } 

To transfer the input stream directly into the database, without storing it in the memory you can use this class taken from here and a bit changed:

public class VarbinaryStream : Stream { private SqlConnection _Connection;  private string _TableName; private string _BinaryColumn; private string _KeyColumn; private int _KeyValue;  private long _Offset;  private SqlDataReader _SQLReader; private long _SQLReadPosition;  private bool _AllowedToRead = false;  public VarbinaryStream(     string ConnectionString,     string TableName,     string BinaryColumn,     string KeyColumn,     int KeyValue,     bool AllowRead = false) {   // create own connection with the connection string.   _Connection = new SqlConnection(ConnectionString);    _TableName = TableName;   _BinaryColumn = BinaryColumn;   _KeyColumn = KeyColumn;   _KeyValue = KeyValue;     // only query the database for a result if we are going to be reading, otherwise skip.   _AllowedToRead = AllowRead;   if (_AllowedToRead == true)   {     try     {       if (_Connection.State != ConnectionState.Open)         _Connection.Open();        SqlCommand cmd = new SqlCommand(                       @"SELECT TOP 1 [" + _BinaryColumn + @"]                             FROM [dbo].[" + _TableName + @"]                             WHERE [" + _KeyColumn + "] = @id",                   _Connection);        cmd.Parameters.Add(new SqlParameter("@id", _KeyValue));        _SQLReader = cmd.ExecuteReader(           CommandBehavior.SequentialAccess |           CommandBehavior.SingleResult |           CommandBehavior.SingleRow |           CommandBehavior.CloseConnection);        _SQLReader.Read();     }     catch (Exception e)     {       // log errors here     }   } }  // this method will be called as part of the Stream ímplementation when we try to write to our VarbinaryStream class. public override void Write(byte[] buffer, int index, int count) {   try   {     if (_Connection.State != ConnectionState.Open)       _Connection.Open();      if (_Offset == 0)     {       // for the first write we just send the bytes to the Column       SqlCommand cmd = new SqlCommand(                                   @"UPDATE [dbo].[" + _TableName + @"]                                             SET [" + _BinaryColumn + @"] = @firstchunk                                          WHERE [" + _KeyColumn + "] = @id",                               _Connection);        cmd.Parameters.Add(new SqlParameter("@firstchunk", buffer));       cmd.Parameters.Add(new SqlParameter("@id", _KeyValue));        cmd.ExecuteNonQuery();        _Offset = count;     }     else     {       // for all updates after the first one we use the TSQL command .WRITE() to append the data in the database       SqlCommand cmd = new SqlCommand(                               @"UPDATE [dbo].[" + _TableName + @"]                                         SET [" + _BinaryColumn + @"].WRITE(@chunk, NULL, @length)                                     WHERE [" + _KeyColumn + "] = @id",                            _Connection);        cmd.Parameters.Add(new SqlParameter("@chunk", buffer));       cmd.Parameters.Add(new SqlParameter("@length", count));       cmd.Parameters.Add(new SqlParameter("@id", _KeyValue));        cmd.ExecuteNonQuery();        _Offset += count;     }   }   catch (Exception e)   {     // log errors here   } }  // this method will be called as part of the Stream ímplementation when we try to read from our VarbinaryStream class. public override int Read(byte[] buffer, int offset, int count) {   try   {     long bytesRead = _SQLReader.GetBytes(0, _SQLReadPosition, buffer, offset, count);     _SQLReadPosition += bytesRead;     return (int)bytesRead;   }   catch (Exception e)   {     // log errors here   }   return -1; } public override bool CanRead {   get { return _AllowedToRead; } }  protected override void Dispose(bool disposing) {   if (_Connection != null)   {     if (_Connection.State != ConnectionState.Closed)       try { _Connection.Close();           }       catch { }     _Connection.Dispose();   }   base.Dispose(disposing); }  #region unimplemented methods public override bool CanSeek {   get { return false; } }  public override bool CanWrite {   get { return true; } }  public override void Flush() {   throw new NotImplementedException(); }  public override long Length {   get { throw new NotImplementedException(); } }  public override long Position {   get   {     throw new NotImplementedException();   }   set   {     throw new NotImplementedException();   } } public override long Seek(long offset, SeekOrigin origin) {   throw new NotImplementedException(); }  public override void SetLength(long value) {   throw new NotImplementedException(); } #endregion unimplemented methods  } 

and the usage:

  using (var filestream = new VarbinaryStream(                             "Connection_String",                             "Table_Name",                             "Varbinary_Column_name",                             "Key_Column_Name",                             keyValueId,                             true))   {     postedFile.InputStream.CopyTo(filestream);   } 

Answer 2

You don't use a file input control. Server side controls are not used in ASP.NET MVC. Checkout the following blog post which illustrates how to achieve this in ASP.NET MVC.

So you would start by creating an HTML form which would contain a file input:

@using (Html.BeginForm("Index", "Home", FormMethod.Post, new { enctype = "multipart/form-data" })) {     <input type="file" name="file" />     <input type="submit" value="OK" /> } 

and then you would have a controller to handle the upload:

public class HomeController : Controller {     // This action renders the form     public ActionResult Index()     {         return View();     }      // This action handles the form POST and the upload     [HttpPost]     public ActionResult Index(HttpPostedFileBase file)     {         // Verify that the user selected a file         if (file != null && file.ContentLength > 0)          {             // extract only the filename             var fileName = Path.GetFileName(file.FileName);             // store the file inside ~/App_Data/uploads folder             var path = Path.Combine(Server.MapPath("~/App_Data/uploads"), fileName);             file.SaveAs(path);         }         // redirect back to the index action to show the form once again         return RedirectToAction("Index");             } }