The FileUpload server control provided by ASP.NET is a powerful control that was quite difficult to achieve in the days of Active Server Pages 3.0. The FileUpload server control allows your end-users to upload one or more files to your server. You can upload maximum filesize of 4MB . If you want to upload larger files, you can control the size of the files that are uploaded by working with settings in either the web.config.comments or web.config file.
Simply drag and drop the File upload control on you form and write the code in the upload button click event. You can specify where you want to save the uploaded file in your server.
FileUpload1.SaveAs("C:\files\" + FileUpload1.FileName)
FileUpload1.SaveAs("C:\\files\\" + FileUpload1.FileName);
Click the following links to see full source code