Hi MarjaR,
Please try the example below
<%@ Page Language="C#" %>
<%@ Register Namespace="CuteWebUI" Assembly="CuteWebUI.AjaxUploader" TagPrefix="CuteWebUI" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void uploader1_UploadCompleted(object sender, UploaderEventArgs[] args)
{
hf1.Value = args.Length.ToString();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<CuteWebUI:UploadPersistedFile ID="uploader1" runat="server" OnUploadCompleted="uploader1_UploadCompleted">
</CuteWebUI:UploadPersistedFile>
<asp:HiddenField ID="hf1" runat="server" />
<asp:Button ID="btnSubmit" runat="server" OnClientClick="return verify()" Text="submit" />
</form>
</body>
</html>
<script type="text/javascript">
function verify()
{
var hf1=document.getElementById("<%=hf1.ClientID %>");
if(hf1.value=="")
{
alert("please upload a file before submit");
return false;
}
return true;
}
</script>
Regards,
Ken