Object reference null in LoadViewState?

Question

When I check if button is clicked or not in LoadViewState

I got this error

Object reference null

In the below code if I click Add Experience button when eTarget = Request.Params["btnAddVisa"].ToString(); get null error

Code:

protected override void LoadViewState(object savedState)
{
  base.LoadViewState(savedState);
  if(IsPostBack)
  {

  eTarget = Request.Params["btnAddVisa"].ToString();
  eTarget = Request.Params["btnAddExperience"].ToString();
  }

  if(eTarget == "Add Visa")
  {
    //
  }

  if(eTarget == "Add Experience")
  {
    //
  }
}

protected void btnAddVisa_Click(sender,e)
{
  //
}

protected void btnAddExperience_Click(sender,e)
{
  //
}

Any ideas? Thanks in advance

Answer 1

You need to check for null values

if(Request.Params["btnAddVisa"]!=null)
    eTarget = Request.Params["btnAddVisa"].ToString();
if(Request.Params["btnAddExperience"]!=null)
    eTarget = Request.Params["btnAddExperience"].ToString();

Answer 2

Request.Params["btnAddVisa"] may not have any object or value.