CODE ON TIME FILE UPLOAD CODE
We are done here and we do not want for other code to execute. The important thing here is to call Response.End() at the end to prevent farther processing of this page.
Then I write file data into the Output stream of the Response object. I set the ContentType property of the Response object to the content type of our file. That will only work if buffering of your pages is turned on (default in ASP.NET). The next step is to clear the Response output buffer to make sure that no other information is being sent to the client besides our file data.
I am using OleDbConnection, OleDbCommand and OleDbDataReader objects to retrieve data. Write data out of database into Output Stream Set ContentType to the ContentType of our file OleDbDataReader dbRead = dbComm.ExecuteReader() Execute command and receive DataReader OleDbCommand dbComm = new OleDbCommand(SQL, dbConn) Define SQL select statement string SQL = " SELECT FileSize, FileData, ContentType FROM tblFile WHERE FileID = " If it was passed, I know that I need to return a file rather than process the user's input:Ĭopy Code // Read file out of the database and returns it to client private void ShowTheFile( int FileID) I check for the FileID parameter being passed to a page. I used the same ASPX page to read and return file data out of the database in my demo project. If your file is placed anywhere under wwwroot, you will need to manually give the database file all the necessary permissions before running my demo project. The local ASP.NET account has to have Write permissions to a database file in order for your code to succeed.
CODE ON TIME FILE UPLOAD UPDATE
That assures that the Primary Key/autonumber FileID field will be populated with the new ID when you call the Update method of your DataAdapter. Also, if you would like to retrieve the newly assigned FileID of the file you have just stored in the database, you need to make sure you set the MissingSchemaAction property of Adapter to MissingSchemaAction.AddWithKey. The important thing to note here is that the OleDbCommandBuilder object needs to be created and initialized with a reference to the OleDbDataAdapter object to build the insert query for us automatically. I create OleDbConnection, OleDbDataAdapter and DataSet objects and then append a row to the only table in DataSet. The code in the above function is very straightforward. The Access database that I used in the demo project has only one table tblFile that has 5 fields defined as follows:įileID – autonumber Filename – text 255 FileSize - long integer ContentType – text 100 FileData – OLE Object Get newFileID if( !dbRow.IsNull( " FileID") ) OleDbCommandBuilder dbCB = new OleDbCommandBuilder(dbAdapt) ĭataTable dbTable = dbSet.Tables We need this to get an ID back from the databaseĭbAdapt.MissingSchemaAction = MissingSchemaAction.AddWithKey OleDbDataAdapter dbAdapt = new OleDbDataAdapter( " SELECT * FROM tblFile", dbConn) OleDbConnection dbConn = new OleDbConnection(GetConnectionString()) The requirements for an HTML form to be able to upload files are very simple: you have to use multipart/form-data encryption and you have to use method of post.Ĭopy Code // Writes file to the database private int WriteToDB( string strName, string strType, ref byte Buffer) Setting Up an HTML Form for File Uploading
Security considerations running the demo project.
CODE ON TIME FILE UPLOAD HOW TO
This article will demonstrate following concepts: NET Framework SDK comes with a few classes that make uploading of the files simple from the web developer point of view. A few wrote their own DLLs and some even wrote purely ASP solutions to this problem using VBScript. Most of the people resorted to 3rd party DLLs. Data had to be retrieved as a safe byte array and decrypted before it could be used. The problem was that due to the encryption type of the form used to submit the file from the client's browser, receiving such files on the server side was a complex task. Back in the ASP world, uploading files via a web page was a tricky problem.
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