TempData is supposed to persist for a subsequent request. However when I check the TempData in a subsequent controller I get a null. Why is TempData[] getting wiped off. Here are my two controllers. I am calling them in succession. So TempData[] should persist from one request to the next. Here is code from controller 1:

```
[HttpGet]
public ActionResult EditCampaign(int? Id)
{

    ViewBag.Banner = bannerText.Replace(" ", "&nbsp;");
    // This is passed in case we need to add a new product or edit one. Then we'll
    // need the campaign id for reference purposes.
    TempData["campaign_id"] = Id;
    TempData["campaignBanner"] = bannerText.Replace(" ", "&nbsp;");
    ViewBag.StartDate = debugger.startDate.ToShortDateString();
    ViewBag.EndDate = debugger.endDate.ToShortDateString();
    int Id1 = Convert.ToInt32(TempData["campaign_id"]);
    int convertedId1 = Id1

```

Here is where I try to get the value in Controller 2:

```
[HttpPost]
public ActionResult EditCampaign(CampaignDTO camps)
{
    // Do this up top. i.e. get the campaign ID
    camps.Id = Convert.ToInt32(TempData["campaign_id"]);
    string success = "";

```

I suspect that assigning the value of TempData in the penultimate line of controller 1 might be wiping off the data. If thats the case that is something new and not documented. Please help.