I keep getting this error and have no idea why. I googled and scanned the asp.net site for two days now so I need some help. The error is:
Object reference not set to an instance of an object
Here's my code:
DropDownList DropDownList1 =(DropDownList)ListView1.InsertItem.FindControl("DropDownList1");
string highToLow = DropDownList1.SelectedValue;
string lowToHigh = DropDownList1.SelectedValue;
if (highToLow == "1")
{
var exmapleFilter = from users in testEntities.users
orderby users.id descending
select users;
ListView1.DataBind();
}
I have the value of the drop down set to 1 for high and 2 for low, and on selected index changed I want to run the ADO.net Entity Framework code to return a sorted list of data.
I'm currently using a linq data source and a list view to show what's in my database.
Thanks.
EDIT:
Here is the stack trace
System.NullReferenceException was unhandled by user code
Message=Object reference not set to an instance of an object.
Source=App_Web_s0ked5y3
StackTrace:
at Default.DropDownList1_SelectedIndexChanged(Object sender, EventArgs e)
in Default:line 120
at System.Web.UI.WebControls.ListControl.OnSelectedIndexChanged(EventArgs e)
at System.Web.UI.WebControls.DropDownList.RaisePostDataChangedEvent()
at System.Web.UI.WebControls.DropDownList.System.Web.UI.IPostBackDataHandler.
RaisePostDataChangedEvent()
at System.Web.UI.Page.RaiseChangedEvents()
at System.Web.UI.Page.ProcessRequestMain(Boolean
includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
InnerException:
Check that you have in your list view
<InsertItemTemplate>
....
<asp:DropDownList ID="DropDownList1" runat="server" />
....
In association with
ListView1.InsertItem.FindControl("DropDownList1");
"Object reference not set to an instance of an object" exception generally occurs when your are trying to use the reference variable whose value is null. It means that there is not corresponding object on heap.
So please make sure to double check your template and load all values in pageload event.
Hope it helps.