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Uploading Files with ASP - Introduction Author

James Crowley

Actions Save as Favourite Share with a Friend PDF Version Report Problem Contents 1. Introduction 2. Getting Started 3. The VB Component 4. Source Code (1) 5. Source Code (2) 6. cUpload: A closer look 7. Compiling the component 8. The upload form 9. Uploading multiple files

Introduction A very frequent question regarding Active Server Pages is "how do I allow a user to upload a file"? Unfortunately, the answer is not particularly straight forward. Active Server Pages itself provides no standard functions, and so you have to rely on either a custom ASP script or a third-party ActiveX DLL. There are a number of ASP script solutions around, however, due to the non-compiled nature of ASP, combined with its fairly limited commands (even compared to VB), these are extremely inefficient and server intensive. The second solution is an ActiveX DLL. Components such as EZsite UpLoad are available as freeware, however, without access to the source code you are limited in terms of flexibility. Therefore, in this tutorial, we will cover all the necessary steps for creating an ASP page, and a VB ActiveX component for use within your script to enable a file to be uploaded.

Hosting Limitations You should be warned that, before we start, not all hosting packages allow you to upload your own ActiveX components. If this is the case, then unfortunately you will have to revert to a pure ASP script.

Getting Started Before we begin, create a new folder called ' uploaddemo' in your C:\inetpub\wwwroot directory (or where-ever else your files are stored for IIS). Create a new file in there called upload.asp, and another called uploadcomplete.asp. Leave these files empty for now. Now, create another directory within 'uploaddemo' called 'files'. This is where our uploaded files are going to be stored. In order for this to work, you need to allow IIS to be given write access to this directory. To do this, go to the Internet Information Services console, select the appropriate web, and then display the properties for the 'files' directory. In the Directory tab, ensure the 'Write' checkbox is selected, and click OK. We're now ready to write some code for upload.asp, where the user will be presented with a form to select a file, and give the file a description. Add the following code to the upload.asp file, and then we'll take a closer look at it.

Please select a file to upload, and enter a description for it.

File:
Description:

As you can see, the form is currently just plain HTML. However, there are a few differences that you may not have come across before. The first is this:

Although at first glance this is a standard form, the enctype property makes a significant difference! When set to multipart/form-data, the form is not posted in the standard format - you will not be able to access the posted data through the standard Request.Form(FieldName) syntax. However, this format does allow files to be transmitted to the

server, as well as form fields. When we create our ActiveX DLL, it will parse this posted data, and save the appropriate part into a new file. The second difference is the line, which uses the "file" input type. This input field allows the user to select a file using an Open dialog. The 'File' input type When a form is submitted using this input box, the file, rather than the filename is transmitted. However, this does have some security consequences... A website could in theory hide this field, with it's value pre-set, and then when the user transmits the form, he/she unknowingly sends the server a file too. Therefore, both IE and Netscape have disabled the value property for this type of input field. The consequence of this, is if you use server-side validation (for, say, checking the length of the description), when you display the form again with the error, you won't be able to use the input tag's value attribute to remember the file the user already selected. Something to bear in mind....

The VB Component Now, we can get started on the VB portion of this tutorial. Create a new ActiveX DLL project in VB, and set the Project's name to 'ASPUploadComponent'. Next, create two Classes to the project, and call them cUpload and cFormItem respectively. cUpload's Instancing property should be set to 5 - MultiUse, and cFormItem's should be set to 2 PublicNotCreatable. Finally, you need to add a reference to the ASP Type Library. To do this, go to Project|References, and check the box next to Microsoft Active Server Pages Object Library, and the Microsoft Scripting Runtime (so we can use the FileSystemObject). Now we can get coding...! Debugging an ASP Component I think you should be warned at this stage that debugging a VB component used in an ASP script is notoriously difficult. You can't simply press F5 to run the component, as it isn't a stand alone executable. Nor can you use the 'Wait for component to be created' option, as IIS isolates any ActiveX components created in your ASP script for security reasons. Unfortunately, this means VB can't gain any debugging information either. Therefore, your only option is to compile your component each time you make a change. However, it gets worse... When your script accesses the component for the first time, it locks the file. Your OCX file is not unlocked again until the IIS service stops, meaning that each time you want VB to re-compile the component you have to restart IIS (and not just the web you are using either... all of IIS!). To restart IIS, go to Services, select World Wide Publishing Service, and click Restart. One last thing... if you would prefer to skip the VB coding section, you can download the source code and binaries here. Then, you can skip to this step.

Source Code (1) First, I'll list all the code that is needed for the component, and then we can examine it more closely. Add the following code to cUpload. Option Explicit '***************************************************************** ' Purpose: Retrieve a file by HTTP protocol and writes this file ' to a location on the webserver '***************************************************************** 'Error Definitions Private Const ERR_FIELD_DOES_NOT_EXIST As Long = vbObjectError + 102 Private MyScriptingContext Private MyRequest Private cFormItems

As ASPTypeLibrary.ScriptingContext As ASPTypeLibrary.Request As Collection

'***************************************************************** ' OnStartPage() ' Purpose: Capture of Active Server Pages objects '***************************************************************** Public Sub OnStartPage(PassedScriptingContext As ScriptingContext)

Set MyScriptingContext = PassedScriptingContext Set MyRequest = MyScriptingContext.Request 'then build the form... Set cFormItems = BuildForm() End Sub '***************************************************************** ' Item() ' Purpose: Return a form item ' Inputs: vKey -- the key or index of the item to return ' Returns: A cFormItem object '***************************************************************** Public Property Get Form(Key As Variant) As cFormItem If FieldExists(Key) = False Then Err.Raise ERR_FIELD_DOES_NOT_EXIST, "UploadIt", "The specified item does not exist" Else Set Form = cFormItems(Key) End If End Property '***************************************************************** ' Count() ' Purpose: Gets the number of form fields ' Returns: The number of form fields '***************************************************************** Public Property Get Count() As Long Count = cFormItems.Count End Property '***************************************************************** ' BuildForm() ' Purpose: Parse the posted form. ' Returns: A collection containing all the forms fields. '***************************************************************** Private Function BuildForm() As Collection On Error GoTo BuildForm_Err 'Variables Dim varByteCount As Variant Dim varHTTPHeader As Variant Dim varDelimeter As Variant Dim varFields As Collection

'the number of bytes sent 'the HTTP header 'the delimiter that divides the fields 'contains all the form fields

Dim lngFormFieldNameStart As Long 'start pos of the form field Dim lngFormFieldNameEnd As Long 'end pos of the form field Dim strFormFieldName As String 'name of the form field Dim lngFormFieldValueStart As Long Dim lngFormFieldValueEnd As Long Dim strFormFieldValue As String Dim Dim Dim Dim Dim

strFileName As String strContentType As String lngFileDataStart As Long lngFileDataEnd As Long lngFileLength As Long

Dim clsFormField As cFormItem

'the filename

'a form item...

'Initialize collection Set varFields = New Collection 'Count total bytes in HTTP-header varByteCount = MyRequest.TotalBytes If varByteCount = 0 Then GoTo BuildForm_ExitProc

'Conversion of bytes to unicode varHTTPHeader = StrConv(MyRequest.BinaryRead(varByteCount), vbUnicode) 'Delimeter string varDelimeter = LeftB(varHTTPHeader, 76) 'Determine where the first FormFieldName starts lngFormFieldNameStart = InStrB(lngFormFieldNameStart + 1, varHTTPHeader, "; name=" & Chr(34)) Do While lngFormFieldNameStart <> 0 'Initialize Form Field object Set clsFormField = New cFormItem 'Determine where FormFieldName ends lngFormFieldNameEnd = InStrB(lngFormFieldNameStart + Len(StrConv("; name=" & Chr(34), vbUnicode)), varHTTPHeader, Chr(34)) + Len(StrConv(Chr(34), vbUnicode)) 'Get the FormFieldName strFormFieldName = MidB(varHTTPHeader, lngFormFieldNameStart + Len(StrConv("; name=" & Chr(34), vbUnicode)), (lngFormFieldNameEnd - Len(StrConv(Chr(34), vbUnicode))) - (lngFormFieldNameStart + Len(StrConv ("; name=" & Chr(34), vbUnicode)))) 'Check for file If MidB(varHTTPHeader, lngFormFieldNameEnd, 2) = ";" Then 'find the start/end positions of filename lngFormFieldValueStart = InStrB(lngFormFieldNameEnd, varHTTPHeader, "filename=" & Chr(34)) + Len (StrConv("filename=" & Chr(34), vbUnicode)) lngFormFieldValueEnd = InStrB(lngFormFieldValueStart, varHTTPHeader, Chr(34)) 'Parse filename from HTTPHeader strFileName = MidB(varHTTPHeader, lngFormFieldValueStart, lngFormFieldValueEnd lngFormFieldValueStart) 'Remove path from filename strFileName = GetFileName(strFileName) 'Check to see if there is a filename If Len(strFileName) = 0 Then GoTo NextItem

'find the start/end positions of content-type lngFormFieldValueStart = InStrB(lngFormFieldNameEnd, varHTTPHeader, vbCrLf & "Content-Type: ") + Len(StrConv(vbCrLf & "Content-Type: ", vbUnicode)) lngFormFieldValueEnd = InStrB(lngFormFieldValueStart, varHTTPHeader, vbCrLf) 'Parse filename from HTTPHeader strContentType = MidB(varHTTPHeader, lngFormFieldValueStart, lngFormFieldValueEnd lngFormFieldValueStart) 'Determine where filedata begins lngFileDataStart = InStrB(lngFormFieldValueEnd, varHTTPHeader, vbCrLf & vbCrLf) + Len(StrConv (vbCrLf & vbCrLf, vbUnicode)) 'Determine where filedata ends lngFileDataEnd = InStrB(lngFileDataStart, varHTTPHeader, vbCrLf & varDelimeter) 'get the length of the file lngFileLength = lngFileDataEnd - lngFileDataStart 'add form field data clsFormField.Add "FileName", strFileName clsFormField.Add "FileLen", lngFileLength clsFormField.Add "ContentType", strContentType 'save the files data to the collection... clsFormField.FileData = MidB(varHTTPHeader, lngFileDataStart, lngFileLength) 'we will search for next field from here... lngFormFieldNameStart = lngFileDataEnd Else 'Determine where filedata begins lngFormFieldValueStart = InStrB(lngFormFieldNameEnd, varHTTPHeader, vbCrLf & vbCrLf) + Len (StrConv(vbCrLf & vbCrLf, vbUnicode))

'Determine where filedata ends lngFormFieldValueEnd = InStrB(lngFormFieldValueStart, varHTTPHeader, vbCrLf & varDelimeter) 'Filter formfieldvalue strFormFieldValue = MidB(varHTTPHeader, lngFormFieldValueStart, lngFormFieldValueEnd lngFormFieldValueStart) 'we will search for next field from here... lngFormFieldNameStart = lngFormFieldValueEnd 'save the fields value clsFormField.Add "Value", strFormFieldValue End If clsFormField.Add "Name", strFormFieldName 'Assign formfieldnames and formfieldvalues to collection varFields.Add clsFormField, strFormFieldName NextItem: 'destroy form field object Set clsFormField = Nothing 'find the next form field object lngFormFieldNameStart = InStrB(lngFormFieldNameStart + 1, varHTTPHeader, "; name=" & Chr(34)) Loop BuildForm_ExitProc: 'Return an array with the formfield names and values Set BuildForm = varFields Exit Function BuildForm_Err: Err.Raise Err, "ASPUploadComponent", "Unhandled error: " & Error End Function '***************************************************************** ' ItemExists() ' Purpose: Determines if a field exists. ' Inputs: strKey -- A string containing the key to search for ' Returns: Whether the entry exists or not '***************************************************************** Public Function FieldExists(ByVal Key As Variant) As Boolean Dim cItem As cFormItem On Error Resume Next Set cItem = cFormItems(Key) If Err = 0 Then FieldExists = True End Function '***************************************************************** ' GetFileName() ' Purpose: Parses the filename from the filepath. ' Inputs: strFilePath -- String containing filepath and filename ' Returns: A string which contains the filename '***************************************************************** Private Function GetFileName(strFilePath) As String Dim intPos As Integer GetFileName = strFilePath For intPos = Len(strFilePath) To 1 Step -1 If Mid(strFilePath, intPos, 1) = "\" Or Mid(strFilePath, intPos, 1) = ":" Then GetFileName = Right(strFilePath, Len(strFilePath) - intPos) Exit Function End If Next End Function

Source Code (2) Now add the following code to cFormItem. This makes up a form field object. Option Explicit 'Error Definitions Private Const ERR_FILESIZE_NOT_ALLOWED As Long = vbObjectError + 103 Private Const ERR_FOLDER_DOES_NOT_EXIST As Long = vbObjectError + 104 Private Const ERR_FILE_ALREADY_EXISTS As Long = vbObjectError + 105 Private Const ERR_FILE_TYPE_NOT_ALLOWED As Long = vbObjectError + 106 Private varFileData As Variant Private cData As Collection '***************************************************************** ' Add() ' Purpose: Adds an item to the field collection ' Inputs: strKey -- the item's key ' strValue -- string containing the value '***************************************************************** Friend Sub Add(ByVal strKey As String, ByVal strValue As String) cData.Add strValue, strKey End Sub '***************************************************************** ' FileData() ' Purpose: Sets the contents of a file ' Inputs: varContent -- the content of the file '***************************************************************** Friend Property Let FileData(varContent As Variant) varFileData = varContent End Property '***************************************************************** ' Properties ' Purpose: Returns various public values '***************************************************************** Public Property Get Value() As String Value = GetVal("FileName") End Property Public Property Get FileSize() As String FileSize = GetVal("FileLen") End Property Public Property Get Name() As String Name = GetVal("Name") End Property Public Property Get ContentType() As String ContentType = GetVal("ContentType") End Property Public Property Get IsFile() As Boolean IsFile = Exists("FileName") End Property '***************************************************************** ' Private Functions '***************************************************************** Private Sub Class_Initialize() Set cData = New Collection End Sub Private Function GetVal(ByVal strKey As String) As String If Exists(strKey) Then GetVal = cData(strKey) Else GetVal = cData("Value") End If End Function

Private Function Exists(ByVal strKey As String) As Boolean Dim strDummy As String On Error Resume Next strDummy = cData(strKey) If Err = 0 Then Exists = True End Function

'***************************************************************** ' SaveFile() ' Purpose: Saves the form entry to a file (if it is one) ' Inputs: strUploadPath -- string containing the directory to upload to ' strFileName -- string containing the filename ' strExcludeFileExtensions -- file extensions to exclude '***************************************************************** Public Sub SaveFile(ByVal strUploadPath As String, ByVal strFileName As String, Optional ByVal strExcludeFileExtensions As String = "", Optional ByVal lMaxByteCount As Long = 0) 'we can only save files... If IsFile = False Then Exit Sub If strFileName = "" Then strFileName = cData("FileName") 'Check to see if file extensions are excluded If strExcludeFileExtensions <> "" Then If ValidFileExtension(strFileName, strExcludeFileExtensions) Then Err.Raise ERR_FILE_TYPE_NOT_ALLOWED, "ASPUploadComponent", "It is not allowed to upload a file containing a [." & GetFileExtension(strFileName) & "] extension" End If End If 'Check for maximum bytes allowed If Not lMaxByteCount = 0 Then If lMaxByteCount < FileSize() Then Err.Raise ERR_FILESIZE_NOT_ALLOWED, "ASPUploadComponent", "File size exceeds maximum size specified" End If End If WriteFile strUploadPath, strFileName End Sub '***************************************************************** ' WriteFile() ' Purpose: Writes the uploaded file to a given directory ' Inputs: strUploadPath -- string containing the directory to upload to ' strFileName -- string containing the filename '***************************************************************** Private Sub WriteFile(ByVal strUploadPath As String, ByVal strFileName As String) On Error GoTo WriteFile_Err 'Variables for file Dim fs As Scripting.FileSystemObject Set fs = New Scripting.FileSystemObject Dim sFile As Object If Not Right(strUploadPath, 1) = "\" Then strUploadPath = strUploadPath & "\" End If If Not fs.FolderExists(strUploadPath) Then Err.Raise ERR_FOLDER_DOES_NOT_EXIST, "ASPUploadComponent", "The folder to upload to doesn't exist" End If If fs.FileExists(strUploadPath & strFileName) Then Err.Raise ERR_FILE_ALREADY_EXISTS, "ASPUploadComponent", "The file [" & strFileName & "] already exists." End If 'Create file Set sFile = fs.CreateTextFile(strUploadPath & strFileName, True)

'Write file sFile.Write varFileData 'Close File sFile.Close Set sFile = Nothing Set fs = Nothing Exit Sub WriteFile_Err: Err.Raise Err.Number End Sub '***************************************************************** ' ValidFileExtension() ' Purpose: Checks if the file extension is allowed ' Inputs: strFileName -- the filename ' strFileExtension -- the fileextensions not allowed ' Returns: boolean '***************************************************************** Private Function ValidFileExtension(ByVal strFileName As String, Optional ByVal strFileExtensions As String = "") As Boolean Dim arrExtension() As String Dim strFileExtension As String Dim i As Integer strFileExtension = UCase(GetFileExtension(strFileName)) arrExtension = Split(UCase(strFileExtensions), ";") For i = 0 To UBound(arrExtension) 'Check to see if a "dot" exists If Left(arrExtension(i), 1) = "." Then arrExtension(i) = Replace(arrExtension(i), ".", vbNullString) End If 'Check to see if FileExtension is allowed If arrExtension(i) = strFileExtension Then ValidFileExtension = True Exit Function End If Next ValidFileExtension = False End Function

'***************************************************************** ' GetFileExtension() ' Purpose: Returns the extension of a filename ' Inputs: strFileName -- string containing the filename ' varContent -- variant containing the filedata ' Outputs: a string containing the fileextension '***************************************************************** Private Function GetFileExtension(strFileName) As String GetFileExtension = Mid(strFileName, InStrRev(strFileName, ".") + 1) End Function

cUpload: A closer look Lets take a closer look at this cUpload class first. After a few public variables for the class, you'll notice the Public Sub OnStartPage(PassedScriptingContext As ScriptingContext) line, which doesn't appear to be called by anything. In fact, this procedure is called by the Active Server Pages engine when the object is initialized in our ASP script, and passes us a ScriptingContext object. This object contains all the objects available to your ASP script; Response, Request, Server etc. In this instance, we are only interested in the Request object (what has been sent to the ASP script), so we save it to our MyRequest object using Set MyRequest = PassedScriptingContext.Request We then proceed to call the BuildForm procedure, which parses the data sent to us via the form on upload.asp. This is where the bulk of our code lies. As the form was posted using the encoding method, we cannot access the posted objects using the standard Request.Form object. Instead, we read the entire HTTP header into a variable. First, we get the length of the header: varByteCount = MyRequest.TotalBytes and then we read the header into varHTTPHeader using varHTTPHeader = StrConv(MyRequest.BinaryRead(varByteCount), vbUnicode) You will notice that we have also converted the header into Unicode. This is to make it easier for us to parse the posted data; instead of receiving binary data, we receive at least some readable characters. Below is a sample of what might now be present in varHTTPHeader. -----------------------------7d130d3810678 Content-Disposition: form-data; name="thefile"; filename="C:\devpad_description.txt" Content-Type: text/plain Developers Pad - the ultimate programming editor. Fully configurable, with syntax highlighting, auto-indent, code library, powerful project view, quick-tag, find & replace, find in files, add-ins and more! -----------------------------7d130d3810678 Content-Disposition: form-data; name="filedescription"

-----------------------------7d130d3810678 Content-Disposition: form-data; name="folder" 0 -----------------------------7d130d3810678-As you can see, each field is seperated by -----------------------------7d130d3810678. Next, we are told the we are type of content, and the field name. In the case of the file, we are also given the filename and content type. Finally, we are given the value of that field. The BuildForm procedure now parses this data, and creates the correct number of form objects. As the delimiter may vary, we check it by taking the first 76 bytes: varDelimeter = LeftB(varHTTPHeader, 76) Next, we find where the first field is by searching for ; name=" lngFormFieldNameStart = InStrB(lngFormFieldNameStart + 1, varHTTPHeader, "; name=" & Chr(34)) Note we use the InStrB function so that we are returned the byte position rather than character position. Now, we start a Do...Loop which continues until lngFormFieldNameStart = 0. For each field, we first initialize the FormField object: Set clsFormField = New cFormItem Next, we find out where the name property is going to end. We do this by searching for a " character (Chr(34)), from the fields starting position, plus the length of ; name=". Now that we have the start and end positions, we can retreive the name of the field: lngFormFieldNameEnd = InStrB(lngFormFieldNameStart + Len(StrConv("; name=" _

& Chr(34), vbUnicode)), varHTTPHeader, Chr(34)) + Len(StrConv(Chr(34), vbUnicode)) strFormFieldName = MidB(varHTTPHeader, lngFormFieldNameStart + _ Len(StrConv("; name=" & Chr(34), vbUnicode)), (lngFormFieldNameEnd - _ Len(StrConv(Chr(34), vbUnicode))) - (lngFormFieldNameStart + _ Len(StrConv("; name=" & Chr(34), vbUnicode)))) Now we check to see if there is a ; after the name field... If there is, we know it is a file, otherwise, it isn't. If it is a file, we proceed to get the filename: and ContentType properties. After the ContentType property, we search for two vbCrLf (new lines), after which is the file data. We now save all this extra file data (filename, file size, content type etc) to the clsFormField object. 'add form field data clsFormField.Add "FileName", strFileName clsFormField.Add "FileLen", lngFileLength clsFormField.Add "ContentType", strContentType 'save the files data to the collection... clsFormField.FileData = MidB(varHTTPHeader, lngFileDataStart, lngFileLength) If the form field isn't a file, we perform a similar operation, except we skip searching for the filename, and just get the form fields value instead. Finally, we save the fields name, and add the clsFormField object to our varFields collection: clsFormField.Add "Name", strFormFieldName 'Assign formfieldnames and formfieldvalues to collection varFields.Add clsFormField, strFormFieldName We then reset the clsFormField, and search for another field to process.... and this continues until we have parsed all the fields. We then return the varFields collection for use by our ASP script.

Compiling the component Phew... that was an awful lot of code to get through. Obviously, we haven't covered every line, but hopefully by now you should get the idea. The clsFormField object is basically used to store information about that field. A standard field will simply have it's name and value recorded. Meanwhile, a file also has a FileSize, ContentType and FileName property. Once parsed, our ASP script can then access all this information, and use the cFormField object's SaveFile method to save each file to the server's hard disk. This will be demonstrated on the next page. First, however, we need to compile our component to a DLL file. To do this, go to File | Make ASPUploadComponent.dll . Before it can be used in your ASP script, however, IUSR_COMPUTERNAMEneeds to be given permission to access the file (and lock it!). To do this, display the file properties from explorer, and give IUSR_COMPUTERNAME read/execute permissions. Now, we are ready to create our other asp page.

The upload form Now that we have created the VB ActiveX DLL component, we can code the uploadcomplete.asp file. Add the following code to uploadcomplete.asp, and we'll take a look at what exactly is going on. <% Option Explicit Dim objUpload, strUploadPath, strMsg, strFileExtensions 'create the ActiveX object Set objUpload = Server.CreateObject("ASPUploadComponent.cUpload") 'set the upload path '***You will need to change this!*** strUploadPath = "C:\inetpub\wwwroot\uploaddemo\files\" 'set the file extensions to exclude strFileExtensions = ".exe;.dll" If objUpload.FieldExists("thefile") = False Then Response.Write "Invalid Post Data" Response.End Else

'file posted... 'attempt to save the file On Error Resume Next objUpload.Form("thefile").SaveFile strUploadPath, objUpload.Form("thefile").Value, strFileExtensions If Err Then 'an error occured... ie file already exists, invalid extension etc strMsg = "Error " & Err.Number & ": " & Err.Description Else 'add description to the database? 'cConn.Execute ("INSERT INTO mydocs (FileName,Description) VALUES ('" & objUpload.Form ("thefile").Value & "','" & objUpload.Form("description").Value) strMsg = "The file was successfully uploaded." End If End If %>

<%=strMsg%>

File Name: <%=objUpload.Form("thefile").Value%>
File Size: <%=objUpload.Form("thefile").FileSize%>
Content Type: <%=objUpload.Form("thefile").ContentType%>
Description: <%=objUpload.Form("description").Value%>

So, lets have a quick look at how this code works. First, we create an instance of the ActiveX DLL using Set objUpload = Server.CreateObject("ASPUploadComponent.cUpload") (as we can't add a reference to the DLL like we would in Visual Basic). The next two lines set the path on the server where the file is going to be uploaded, and we set strFileExtensions, specifying the file extensions to exclude. (This is always a good idea, as you don't want your users uploading executables to your server!). Next, we check to see if the field, 'thefile', exists, using the FieldExists property exposed by the objUpload object: If objUpload.FieldExists("thefile") = False Then If it doesn't, we know the form has not been posted correctly, or the user has not selected a file. If it does exist, we try to save the file: objUpload.Form("thefile").SaveFile strUploadPath, objUpload.Form("thefile").Value, strFileExtensions The SaveFile method uses the following parameters: SaveFile UploadFolder, FileName, [ExcludeFileExtensions], [MaxByteCount] If an error occurs, we trap the error, and otherwise, tell the user the file has been uploaded. At this stage, we could also add the description field to a database, for example. The rest of the page outputs the HTML, and displays the information exposed about the file that was uploaded...

Uploading multiple files One final "how-to"... Unfortunately, the file HTML input tag doesn't support selecting multiple files. However, you can have more than one file field in your form, with a different name. Therefore, you can upload multiple files using the component we built using objUpload.Form("file1").SaveFile strUploadPath, objUpload.Form("file2").Value objUpload.Form("file2").SaveFile strUploadPath, objUpload.Form("file2").Value etc... And there you have it... an fully featured upload facility and re-usable ActiveX component. Easy, wasn't it.... hmmm... maybe it will improve in ASP.NET!

James first started writing tutorials on Visual Basic in 1999 whilst starting this website (then known as VB Web). Since then, the site has grown rapidly, and James has written numerous tutorials, articles and reviews on VB, PHP, ASP and C#. In October 2003, James formed the company Developer Fusion Ltd, which owns this website, and also offers various development services. In his spare time, he's a 3rd year undergraduate studying Computer Science in the UK. He's also a Visual Basic MVP.

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