wpf xaml checkbox template in style - wpf

Question

first post so please go easy.
I am trying to get the value of a checkbox from another page (this is part of a navigation form in WPF project), but it always resets the value to false as soon as the page is changed. How do I get the IsChecked value to bind properly? I am learning just starting to work with WPF so the template is very basic, if there is a better way to do this then I am open to it.
Also the code behind page is vb.net not c# if that is going to play a part.
the style is called as follows:
<CheckBox Content="Photo" x:Name="OT_Photo" Grid.Row="0" Grid.Column="0" Style="{StaticResource ElementCheckbox}" />
There are several hundred checkboxes across these pages so I would very much like to avoid variables for each one.
The style is in 'Application.xaml'
<Style TargetType="CheckBox" x:Key="ElementCheckbox">
<Setter Property="IsThreeState" Value="True" />
<Setter Property="IsChecked" Value="{Binding IsChecked ,Mode=TwoWay}" />
<Setter Property="Foreground" Value="Navy" />
<Setter Property="FontSize" Value="14" />
<Setter Property="Margin" Value="15,4,0,4" />
<Setter Property="HorizontalAlignment" Value="Left" />
<Setter Property="MaxWidth" Value="500" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type CheckBox}">
<DockPanel DockPanel.Dock="Left">
<Border x:Name="Border" CornerRadius="0" VerticalAlignment="Top">
<Image Height="20" Width="20" Name="CheckMark" />
</Border>
<TextBlock x:Name="CheckText" Text="{TemplateBinding Content}" Margin="5,0,0,0" FontSize="{TemplateBinding FontSize}" TextWrapping="Wrap" HorizontalAlignment="Left" VerticalAlignment="Top" />
</DockPanel>
<ControlTemplate.Triggers>
<Trigger Property="IsChecked" Value="{x:Null}">
<Setter TargetName="CheckMark" Property="Source" Value="CheckBoxNull.png" />
</Trigger>
<Trigger Property="IsChecked" Value="false">
<Setter TargetName="CheckMark" Property="Source" Value="CheckBoxCross.png" />
</Trigger>
<Trigger Property="IsChecked" Value="true">
<Setter TargetName="CheckMark" Property="Source" Value="CheckBoxTick.png" />
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Effect" TargetName="Border">
<Setter.Value>
<DropShadowEffect ShadowDepth="1" Color="Blue" Opacity="1" BlurRadius="2"/>
</Setter.Value>
</Setter>
<Setter Property="Foreground" Value="Blue" TargetName="CheckText" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
Thanks in advance of any help!
I should add I have been stuck on this for over a day, I have tried template binding, binding paths, and an on click procedure based on the c# answers I have found already. always resulting in the checkbox being reset though.

Answer 1

Solved
My problem was unrelated to the checkbox as it happened, the page was not named statically so the properties always served the default values. (rookie mistake - much shame)
on the up side the code above works perfectly (in its limited way) if anyone wants to pinch it!
VB.NET:
Private Sub MainForm_Loaded(sender As Object, e As RoutedEventArgs) Handles MainForm.Loaded
Me.NavigationService.Navigate(ContactDetailsPage)
End Sub
instead of XAML stating the source:
<NavigationWindow x:Name="MainForm" x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="" Source="ContactDetails.xaml">

Answer 2

I think the problem is that you define your binding in your template instead in your control. You usually don't do bindings in your templates unless it is a DataTemplate.
<CheckBox IsChecked="{Binding Value}" Content="Photo" x:Name="OT_Photo" Grid.Row="0" Grid.Column="0" Style="{StaticResource ElementCheckbox}" />
Don't forget to set de DataContext for your object.
You might want to test the binding first without templating. If this doesn't solve your problem it might be useful to post the code-behind as well.