use viewstate is a server control which will be clear by using postback so first store the value in a javascript and then use it as follows
THE Java Script Method:
function OnClientAsyncFileUploadComplete(sender, args) {
__doPostBack('filename', args.get_fileName());
}
function saveLogo(ImageName) {
__doPostBack('filename', args.get_fileName());
}
in page load plese put the following code:
IN .CS
if (IsPostBack)
{
string eventTarget = this.Request["__EVENTTARGET"];
if (eventTarget == "filename")
{
ViewState["EIName"] = this.Request["__EVENTARGUMENT"].ToString();
}
}
ViewState["EIName"] contains the file name
you can use any where in the page