NullReferenceException after creating new form instance

Asked Feb 04 '17 at 16:11

Active Feb 04 '17 at 16:24

Viewed 32 times

So I am programming some kind of a member data-storage application and I'm getting a NullReferenceException when I try to create a new form instance.

Code in the main:

List<Object> list_objects = objects.get_Objects();

        try
        {
            New_Object obj = new New_Object(this, objects, list_objects.ElementAt(lv_data.FocusedItem.Index));
            obj.Show();
        }catch(NullReferenceException)
        {
            MessageBox.Show("No object selected.");
        }

Code in "New_Object"

public New_Object(Main main, Objects objects, Object obj)
    {
        btn_create.Text = "Cahnge";
        btn_create.Click += btn_change_Click;
        this.obj = obj;
    }

There is an existing object in list_objects with the index of 0 and the lv_data.FocusedItem.Index is also 0, so why is this not working?

Thanks for helping and explaining

edited Feb 04 '17 at 16:24

Uwe Keim

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asked Feb 04 '17 at 16:11

Lostflash

Means that either `list_objects` or `lv_data` is `null` – Jeroen van Langen Feb 04 '17 at 16:14
Which of your variables is null ? – PhillipH Feb 04 '17 at 16:14
Did you try stepping through with a debugger? – Peter Torr - MSFT Feb 04 '17 at 16:14
1

@JeroenvanLangen or `objects` or `lv_data.FocusedItem` or `btn_create` – DavidG Feb 04 '17 at 16:19
The exception details will let you know exactly which line it occurred in. Simply set a breakpoint there and inspect everything that could be null. – Troels Larsen Feb 04 '17 at 16:20
It says btn_create is null. But why? It is in the form. – Lostflash Feb 04 '17 at 16:24
Ok I suck :D I forgot "InitializeComponent();" <, – Lostflash Feb 04 '17 at 16:30

NullReferenceException after creating new form instance

0 Answers0