Validate uploaded file extension using AjaxFileUpload and change file name in ASP.Net

Hi nauna,

Please refer below sample.

HTML

<asp:ToolkitScriptManager runat="server">
</asp:ToolkitScriptManager>
<asp:AjaxFileUpload ID="AjaxFileUpload11" runat="server" MaximumNumberOfFiles="5"
    Width="400px" OnUploadComplete="OnUploadComplete" />

Namespaces

C#

using System.IO;
using AjaxControlToolkit;

Vb.Net

Imports System.IO
Imports AjaxControlToolkit

Code

C#

protected void OnUploadComplete(object sender, AjaxFileUploadEventArgs e)
{
    string fileName = Path.GetFileName(e.FileName);
    string ext = Path.GetExtension(e.FileName);
    if (ext == ".jpg" || ext == ".jpeg" || ext == ".gif" || ext == ".png")
    {
        fileName = Guid.NewGuid().ToString() + ext;
    }
    AjaxFileUpload11.SaveAs(Server.MapPath("~/Uploads/" + fileName));
}

VB.Net

Protected Sub OnUploadComplete(ByVal sender As Object, ByVal e As AjaxFileUploadEventArgs)
    Dim fileName As String = Path.GetFileName(e.FileName)
    Dim ext As String = Path.GetExtension(e.FileName)
    If ext = ".jpg" OrElse ext = ".jpeg" OrElse ext = ".gif" OrElse ext = ".png" Then
        fileName = Guid.NewGuid().ToString() & ext
    End If
    AjaxFileUpload11.SaveAs(Server.MapPath("~/Uploads/" & fileName))
End Sub