Question

I am using asp.net 4, .net 4 and masterpages. I added in the following code to my child page

    Private Sub FoodChain_Init(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Init

    MyBase.OnInit(e)

    PopulateDropdowns()
    HideQuestionDiv()
    HideDropdowns()

End Sub

and ran my app. The app runs fine but when I went back to the design view I now get an error saying “object reference not set to an instance”. This is only during design time view and referencing the main place holder.

Is this a bug or am I missing something ? As I said the application runs fine and there are now issues during runtime.

Answer 1

Try putting all your databinding inside the following. (sorry about the c# code). I think it is Me.DesignMode in VB.

if (!this.DesignMode)
{

PopulateDropdowns();
HideQuestionDiv();
HideDropdowns();

}

I’m not sure if this works correctly for nested user controls but worth a try. Note that this won’t work inside a constructor, only other events.

MSDN here.