Check whether an element exists in mvc formcollection

I know that the question was about FormCollection but for those using IFormCollection here is the solution.

public IActionResult GetProjectDelivery(IFormCollection data)
{
    if (data.ContainsKey("AnElement"))
    {
        // do stuff
    }
    else
    {
        // do stuff
    }
}

Try using .Contains():-

 public JsonResult FullRetailerUpdate(FormCollection data)
 {
    if (data.AllKeys.Contains("AnElement")) 
    {
      // Your Stuff
    }
    else
    {
      // Your Stuff
    }   
 }