Validating filenames with regularexpressionvalidator
I previously wrote an MSDN article on how to effectively use this control in your ASP. This article is a reintroduction to the file upload process, but instead of using the File Field control, I will show you how to effectively use the new File Upload server control that is offered through ASP. It is important to note that while this article introduces you to the new File Upload server control, it is still quite possible to use the File Field control in your applications today. There are some important items we should go over for this example so you understand all the needed pieces to make this work.
For the example in Listing 1 to work, you have to make the destination folder on the server writeable for the account used by ASP.
NET so the file can be saved to the specified folder. NET account is not enabled to write to the folder you want, simply open up Microsoft Windows Explorer and navigate to the folder to which you want to add this permission.
Right-click on the folder (in this case, the Uploads folder), and then select Properties.
If you want to apply this to only the application you are working with, apply this node to the web.config file of your application, overriding any setting that is in the web.config.comments file. The value given the execution Timeout attribute is the number of seconds the upload is allowed to occur before being shut down by ASP. If you are going to allow large files to be uploaded to the server, you are also going to want to increase this value along with the max Request Length value. Content Length & " kb" & _ "Content type: " & _ File Upload1. Files Dim i As Integer = 0 Do Until i = uploaded Files.
One negative with increasing the size of a file that can be uploaded is that there are hackers out there who attack servers by throwing a large number of requests at them. Count Dim user Posted File As Http Posted File = uploaded Files(i) Try If (user Posted File.
If it was unsuccessful, the page displays an error message describing why the upload failed. Text = "Location where saved: " & _ filepath & "\" & _ System. Files property lets you gain control over all the files that are uploaded from the page.
By default, the maximum size of a file to be uploaded to the server using the File Upload control is around 4MB. In the end, the files are saved to the Uploads folder in the root directory of the server.
Here I will show you regular expressions for various file formats to validate a file upload.
Regular Expression to validate video file formats Here my need is to validate a file for only video formats, so that the user is able to upload the file in the valid video formats. Net application that contains a file upload control and with a regular expression validation control.
This is ideal for browsers that allow client-side use of the validation controls because it forces the checking to be done on the client; the file is not uploaded to the server if the signature isn't one you allow.
Listing 3 shows you an example of using validation controls to accomplish this task. NET page uses validation controls so that the end user can only upload .mp3, .mpeg, or .m3u files to the server. Validating the file type using validation controls Using Validation controls is not a foolproof way of controlling the files that are uploaded to the server. NET page to perform a client side validation of the file extension (in just a textual manner). Checking the file type on the server Visual Basic Protected Sub Button1_Click(By Val sender As Object, _ By Val e As System. Has File Then Dim file Ext As String file Ext = System.