In this article I will explain with an example, how to upload file without clicking Submit Button using FileUpload control in ASP.Net using C# and VB.Net.
 
 

HTML Markup

The HTML Markup consists of following controls.
FileUpload – For selecting file.
Label – For displaying success message.
The Label is made hidden by setting Visible property to FALSE.
 
Button – For uploading selected file.
The Button has been assigned with an OnClick event handler.
The Button is made hidden as its clicking will be simulated using JavaScript.
<asp:FileUpload ID="fuUpload"runat="server" />
<br /><br />
<asp:Label ID="lblMessage" runat="server" Text="File uploaded successfully." ForeColor="Green" Visible="false" />
<asp:Button ID="btnUpload" Text="Upload" runat="server" OnClick="Upload" Style="display: none" /> 
 
 

Namespaces

You will need to import the following namespace.
C#
using System.IO;
 
VB.Net
Imports System.IO
 
 

Uploading File without clicking Submit Button using FileUpload control

Inside the Page_Load event handler, the FileUpload control has been assigned with an onchange event handler which calls the UploadFile JavaScript function.
C#
protected void Page_Load(object sender, EventArgs e)
{
    fuUpload.Attributes["onchange"] = "UploadFile(this)";
}
 
VB.Net
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
    fuUpload.Attributes("onchange") = "UploadFile(this)"
End Sub
 
 

Uploading file using JavaScript

UploadFile

The UploadFile JavaScript function, accepts FileUpload control as a parameter.
Inside the UploadFile JavaScript function, a check is performed if file is selected or not. If selected then it will trigger the click event of the Submit Button.
<script type="text/javascript">
    function UploadFile(fileUpload) {
        if (fileUpload.value != '') {
            document.getElementById("<%=btnUpload.ClientID %>").click();
        }
    }
</script>
 
 

Saving file using C# and VB.Net

When the Upload Button is clicked, it saves the uploaded file to a folder.
Finally, the Visible property of a Label control is set to TRUE.
C#
protected void Upload(object sender, EventArgs e)
{
    fuUpload.SaveAs(Server.MapPath("~/Uploads/" + Path.GetFileName(fuUpload.FileName)));
    lblMessage.Visible = true;
}
 
VB.Net
Protected Sub Upload(sender As Object, e As EventArgs)
    fuUpload.SaveAs(Server.MapPath("~/Uploads/" + Path.GetFileName(fuUpload.FileName)))
    lblMessage.Visible = True
End Sub
 
 

Screenshot

Upload File without clicking Submit Button using FileUpload control in ASP.Net
 
 

Browser Compatibility

The above code has been tested in the following browsers.
Microsoft Edge  FireFox  Chrome  Safari  Opera
* All browser logos displayed above are property of their respective owners.
 
 

Downloads

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