Finally ASP.NET 2.0 has a FileUpLoad control, which allows developers to drop the control on a page and let it browse a file and upload it on the server.

To create a control, simply drop the FileUpload control from Toolbox to a Web page. The following code adds the FileUpLoad control:

<asp:FileUpLoad id="FileUpLoad1" runat="server" />

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" />

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.";
}
}

The final page looks like Figure 1.

Figure 1. FileUpLoad control

Now if you run the sample, browse a file, and click on Upload File button, the output looks like Figure 2.

Figure 2. FileUpLoad control in action

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">
</asp:RegularExpressionValidator>

Figure 3. Validating images only.

I was trying to upload a file with over 10MB and was getting error and this is why?

<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]
/>