CODEWITHSUNDEEP
c#windows-phone-7
Nikoloz Shvelidze
Nikoloz Shvelidze

Reputation: 1614

WP7: NullReference Exception when referring to element

i'm developing a Windows Phone 7.1 Application, this is the ApplicationBar :

<phone:PhoneApplicationPage.ApplicationBar>
  <shell:ApplicationBar IsVisible="True"
                        IsMenuEnabled="True">
    <shell:ApplicationBarIconButton IconUri="/add.png"
                                    Text="Add"
                                    x:Name="addItem"
                                    Click="addItem_Click" />
    <shell:ApplicationBarIconButton IconUri="/edit.png"
                                    Text="Edit"
                                    x:Name="edit"
                                    IsEnabled="False"
                                    Click="edit_Click" />
    <shell:ApplicationBarIconButton IconUri="/remove.png"
                                    Text="Remove"
                                    x:Name="remove"
                                    IsEnabled="False"
                                    Click="remove_Click" />
    <shell:ApplicationBar.MenuItems>
      <shell:ApplicationBarMenuItem Text="Clear"
                                    x:Name="clr"
                                    Click="clr_Click" />
      <shell:ApplicationBarMenuItem Text="Logout"
                                    Click="ApplicationBarMenuItem_Click"
                                    x:Name="logout" />
    </shell:ApplicationBar.MenuItems>
  </shell:ApplicationBar>
</phone:PhoneApplicationPage.ApplicationBar>

when i refer to its elements, named 'edit' and 'remove' :

edit.IsEnabled = true;
        remove.IsEnabled = true;

it gets nullreference exception. any solutions?

Upvotes: 1

Views: 505

Answers (1)

Alexis Mathieu
Alexis Mathieu

Reputation: 692

you have to retreive the object in code behind :

ApplicationBarIconButton edit = ApplicationBar.Buttons[1] as ApplicationBarIconButton;
edit.IsEnabled = true;

Upvotes: 5

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