Hi Joe,

 

You can refer to the following method:

 

 protected void UploadAttachments1_FileValidating(object sender, UploaderEventArgs args)  
    {   
        string disabledExtList = "aspx,asp,ashx,html,htm,mht,exe,dll,php,jsp";        

        //validate the extensions  
        string ext=Path.GetExtension(args.FileName).TrimStart('.').ToLower();  
        ext = "," + ext + ",";  
        string list="," + disabledExtList.ToLower() + ",";  
        if (list.IndexOf(ext) != -1)  
        {  
            throw (new Exception("Invalid file type!"));  
        }  
    }  

 

Thanks for asking

Eric@cutesoft.net