Using file upload control to upload the file

Step 1:
Drop the FileUpload control from Toolbox to a Web page. The following code adds the FileUpLoad control:

asp:FileUpLoad id="FileUpLoad1" runat="server"

Step 2:
To support file upload, we need to add a Button control:


asp:Button id="UploadBtn" Text="Upload File" OnClick="UploadBtn_Click" runat="server" Width="105px"

Step 3:
Now on this button click event handler, we need to call SaveAs method of FileUpLoad control, which takes a full path where the file will be uploaded.

protected void UploadBtn_Click(object sender, EventArgs e)
{
if (FileUpLoad1.HasFile)
{

FileUpLoad1.SaveAs(@"C:\temp\" + FileUpLoad1.FileName);
Label1.Text = "File Uploaded: " + FileUpLoad1.FileName ;
}
else
{
Label1.Text = "No File Uploaded.";
}
}

Step 4:
You can restrict the FileUpload control to upload a file type. For example, I wanted to upload images (Jpgs and Gifs) only so I put a validator, which allows Gifs and Jpegs only.

asp:RegularExpressionValidator
id="FileUpLoadValidator" runat="server"
ErrorMessage="Upload Jpegs and Gifs only."
ValidationExpression="^(([a-zA-Z]:)|(\\{2}\w+)\$?)(\\(\w[\w].*))(.jpg|.JPG|.gif|.GIF)$"
ControlToValidate="FileUpload1"

Step 5:
The default size of files uploaded by the FileUpload control is 4MB. So if we try to upload the files larger than 4MB, it won't let you do so.  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. Make sure this node resides between the nodes in the configuration file. This number is in KB.

httpRuntime
executionTimeout = "110" [in Seconds][number
maxRequestLength = "4096" [number]
requestLengthDiskThreshold = "80" [number]
useFullyQualifiedRedirectUrl = "false" [true|false]
minFreeThreads = "8" [number]
minLocalRequestFreeThreads = "4" [number]
appRequestQueueLimit = "5000" [number]
enableKernelOutputCache = "true" [true|false]
enableVersionHeader = "true" [true|false]
apartmentThreading = "false" [true|false]
requireRootedSaveAsPath = "true" [true|false]
enable = "true" [true|false]
sendCacheControlHeader = "true" [true|false]
shutdownTimeout = "90" [in Seconds][number]
delayNotificationTimeout = "5" [in Seconds][number]
waitChangeNotification = "0" [number]
maxWaitChangeNotification = "0" [number]
enableHeaderChecking = "true" [true|false]