C# Get Full File Path

You are mixing up client and server beavior, which is easy to do when you are testing locally. The issue you are having is that the FileUploadControl (and HTML file uploading in general) is specifically designed to not provide you with the full path to the file. That would be a privacy breach. What it is designed to give you is the binary data of the file that was uploaded itself. Specifically you should query the properties on FileUploadControl: FileBytes or FileContent.

Just to further clarify the issue, what would happen if the browser user was actually on a physically different machine from the web server (the usual case)? What good would the full path of the file on the client machine be to you on the server?

Server.MapPath will return the physical path to a file in or below the application root. If that path you list is outside the application root, Server.MapPath will not work.

You can map a virtual directory to a folder you want to use to hold file uploads, which you can then discover with Server.MapPath.