We use file upload web control in our sites, where we want only valid image types to be uploaded.
Without talking much -> here are 3 ways to do it.
1. Accept attribute of fileUpload control - Doesnt work with most of the browsers (Bad with IE itself)
2. Regular Expression validator for FileUpload
<asp:RegularExpressionValidator id="UpLoadValidator" runat="server" ErrorMessage="Upload Images only." ValidationExpression="^(([a-zA-Z]:)|( \\{2}\w+)\$?)(\\(\w[\w].*))(.jpg|.png|.bmp|.jpeg|.gif)$ " ControlToValidate="FileUpload1"> </asp:RegularExpressionValidator>
This is Not very handy when using AJAX controls on page- Both javascripts dont like each other :)
![\\{2}\w+)\$?)(\\(\w[\w].*))(.jpg|.png|.bmp|.jpeg|.gif)$](file://%7b2%7d/w+)/$?)((%5Cw%5B%5Cw%5D.*))(.jpg%7C.png%7C.bmp%7C.jpeg%7C.gif)$){kind=link}
3. Write a code behind function in a very simple way - Most robust way to use it. - Very Generic can be used for any file types.
private bool IsFileValid()
{
string [] allowedImageTyps = {"image/gif", "image/pjpeg", "image/bmp","image/x-png"};
StringCollection imageTypes = new StringCollection();
imageTypes.AddRange(allowedImageTyps);
if (imageTypes.Contains(FileUpload1.PostedFile.ContentType))
return true;
else
{
return false;
}
}
NOTE - use FileUpload1.PostedFile.ContentType and not the file name to check the Extension
Leave a comment if this helped you
Comments
- Anonymous
November 05, 2009
Thanks a lot.Its working greatly.Why its not working with ajax??